Companion October2011

The essential publication for BSAVA membersThe essential publication for BSAVA members

companionOCTOBER 2011

Antibiotic guidelinesNew advice explained P4

Dispensing antimicrobialsRetaining the rightP8

How to use antibioticsIn surgical patientsP15

Are you PROTECTing your antibacterials

01 OFC October.indd 1 20/09/2011 10:58

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companion

companion is published monthly by the British Small Animal Veterinary Association, Woodrow House, 1 Telford Way, Waterwells Business Park, Quedgeley, Gloucester GL2 2AB. This magazine is a member only benefit and is not available on subscription. We welcome all comments and ideas for future articles.

Tel: 01452 726700Email: [email protected]

Web: www.bsava.com

ISSN: 2041-2487

Editorial BoardEditor Mark Goodfellow MA VetMB CertVR DSAM DipECVIM-CA MRCVSSenior Vice-President Grant Petrie MA VetMB CertSAC CertSAM MRCVS

CPD Editorial TeamIan Battersby BVSc DSAM DipECVIM-CA MRCVSEsther Barrett MA VetMB DVDI DipECVDI MRCVSSimon Tappin MA VetMB CertSAM DipECVIM-CA MRCVSPatricia Ibarrola DVM DSAM DipECVIM-CA MRCVS

Features Editorial TeamCaroline Bower BVM&S MRCVSAndrew Fullerton BVSc (Hons) MRCVS

Design and ProductionBSAVA Headquarters, Woodrow House

No part of this publication may be reproduced in any form without written permission of the publisher. Views expressed within this publication do not necessarily represent those of the Editor or the British Small Animal Veterinary Association.

For future issues, unsolicited features, particularly Clinical Conundrums, are welcomed and guidelines for authors are available on request; while the publishers will take every care of material received no responsibility can be accepted for any loss or damage incurred.

BSAVA is committed to reducing the environmental impact of its publications wherever possible and companion is printed on paper made from sustainable resources and can be recycled. When you have finished with this edition please recycle it in your kerbside collection or local recycling point. Members can access the online archive of companion at www.bsava.com .

3 Association NewsLatest news from BSAVA

47 Guide to the GuidelinesIan Battersby explains how and why he became interested in veterinary antibiotic prescribing practices

810 Dispensing antimicrobial drugsJohn Bonner reports on the threat to the professions right to dispense its current range of antimicrobial products

1114 Clinical ConundrumConsider a case of alopecia, crusts and pruritus in a young Great Dane

1519 How ToUse antibiotics in surgical patients

2021 PublicationsThe fundamentals of surgery, and MRSA: a zoonotic infection

22 PetsaversLatest fundraising news

23 CPDJon Bowen explores the basis of elimination, spraying and inter-cat conflict problems

2425 World CongressCongress gets in on antimicrobial debate

2627 WSAVA NewsThe World Small Animal Veterinary Association

2829 The companion InterviewTim Nuttall

30 Meet Your RegionSpotlight on North West Region

31 CPD DiaryWhats on in your area

Main cover graphic: David Gregory & Debbie Marshall, Wellcome Images

Additional stock photography Dreamstime.com Georgiy Pashin; Isselee; James Grogan; Ljupco Smokovski; Marcin Sadowski; Pseudolongino; Todd Davis

Antibiotic resistance and nosocomial infections seem to feature in the press almost daily nowerdays. In recent years, coincident with wider recognition of resistant bacteria such as MRSA in our patients, the veterinary professions use of antibiotics has some under the spotlight as a possible factor contributing to the increasing prevalence of bacterial resistance seen in human patients. So at present veterinary surgeons are faced with the dual problem of treating more and more resistant bacterial infections, whilst the threat of withdrawal of the right to prescribe certain antibiotics hangs over our heads. The way we treat our patients has potential implications for human health and human healthcare. The time has come for the veterinary profession to take a coordinated responsible approach to its prescribing practices.

Recently the Small Animal Medicine Society (SAMSoc) sought to address the need for rational guidelines to antibiotic selection; using the most appropriate drugs for the correct duration, to maximise clinical efficacy but minimise selection of resistant bacteria. In this special issue of companion, we are proud to launch the SAMSoc antibiotic prescribing guidelines produced in association with BSAVA and to include other articles outlining the problem and suggesting some solutions.

To emphasise the threat to our antibiotic prescribing practices, John Bonner reviews the recent political activity as far afield as the European Parliament. In pages 4 to 7 Ian Battersby describes how the differences in prescribing practices between human and veterinary hospitals was brought into focus for him, and ultimately led him down the path which resulted in the production of SAMSoc/BSAVA guidelines. In our usual CPD features Jonathan Bray takes a close look at the use of perioperative antibiotics, and Tim Nuttall and Ana Mafalda Lourenco Martins describe the problem-oriented approach to a case of pyoderma involving multidrug-resistant bacteria.

We hope you will find this issue thought provoking and informative and we look forward to hearing your experiences of implementing rational antibiotic usage protocols in your practices.

Mark Goodfellow companion EditorIan Battersby companion CPD Editor

Antimicrobial editionThis special edition of companion is largely focused on antimicrobial issues to celebrate the launch of a new SAMSoc/BSAVA poster to encourage greater knowledge and responsibility in prescribing protocols. Our Editors explain

John Bonner reports on the threat to the professions right

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ASSOCIATION NEWS

BSAVA have updated their practice guidelines on reducing the risk of MRSA and MRSP, with the help of Dr Tim Nuttall, Senior Lecturer at the University of Liverpool. The in-depth advice covers routine measures to prevent the spead of MRSA and MRSP, managing infected patients and staff/environment screening. The update also includes instructional video clips on thorough hand washing practices and downloadable posters for display in veterinary premises.

Dr Nuttall has also contributed an article entitled Meticillin-resistant staphylococci in companion animals, which gives a detailed account of the background to antimicrobial-resistant bacteria and also practical guidance on ways to diagnose, treat and avoid infections.

The updated MRSA guidance and article can be found in the Advice section at www.bsava.com. In addition the Bella Moss Foundation will be offering a free webinar titled Recent advances in the treatment and control of meticillin-resistant staphylococci on 8 December for more information email [email protected].

OCTOBERS BONANZA PRIZE

In August the Veterinary Poisons Information Service (VPIS) contacted BSAVA for help in letting the profession know that various agencies and landowners are stepping up their efforts to find out why some dogs have fallen ill while on countryside walks.

Cases of so-called Seasonal Canine Illness (SCI) occurred during the Autumn of 2009 and 2010 in Nottinghamshire, Lincolnshire, East Anglia and Warwickshire, although there have been reports from further afield.

Clinical signs include severe vomiting, pyrexia, diarrhoea, shaking and trembling, and have generally been displayed by animals within 24 hours of walking in the countryside, especially in woodlands. A small number of dogs have died, but the cause remains unknown.

Vets are advised to:

Report suspected cases in Nottinghamshire to [email protected]

Collect and store samples for possible use by Nottingham University (see www.vpisuk.co.uk)

Encourage pet owners to complete the Animal Health Trust questionnaire (see www.aht.org.uk)

Display the questionnaire prominently in surgeries.

Remember: BSAVA members have access to the BSAVA/VPIS Poisons Triage Tool for help with common suspected poisonings in cats and dogs at www.bsava.com.

NOMINATE FOR BSAVA AWARDSA final reminder to all members that 11 November is the deadline for nominating a mentor or inspiring colleague in any of the BSAVA Awards categories. These awards are in recognition of the contributions made by individuals working in the field of small animal medicine and surgery. The Awards Committee, which compromises the Presidents of the BSAVA, RCVS and BVA together with the chairmen of the BSAVAs Scientific and Publications Committees, meet every December to consider nominations for Awards. The Committee cannot make nominations itself and therefore relies on the BSAVA membership putting forward names for consideration. Visit the website for more information or email [email protected] to request a nomination form.

New moves to tackle seasonal canine illness

Updated guidelines on MRSA and MRSP

Last month we told you about the Big Booking Bonanza where each month, everyone registered for Congress will go into a draw, so not only will you save money by booking before the Early Bird deadline, you will also get the chance to walk away with a great prize. In October the prize is kindly sponsored by Willows Veterinary Centre and Referral Service. Partner at Willows, Peter Renwick says, Given our involvement in professional development we are proud to sponsor one of the Big Booking Bonanza prizes a complete set of the latest BSAVA Manuals, worth more than 3000. This will make a great addition to any practitioners bookshelf.

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PRESCRIBING

As clinicians we all have different levels of interest and knowledge of antimicrobial usage but we all appreciate that judicious use is an important issue that will never go away.

For me this was highlighted following a trip to A&E with a swollen painful hand following a nasty cat bite. The second course of antibiotics I had received from the GP was having no effect and I was becoming concerned.

I had a detailed discussion with the A&E consultant and asked why we couldnt change the antibiotic to one I hadnt had before. It was at this point I got an insight to the restrictions of prescribing these drugs in hospitals. The doctor rather patiently listened to my concerns and then said current prescribing protocol means that I can only prescribe you potentiated amoxicillin or clarithromycin for a bite injury without a culture. There are a number of strict criteria I must meet to prescribe certain drug groups. For example to prescribe a cephalosporin I must have a positive culture with sensitivities and written authorization from our head microbiologist.

For me this was quite a profound moment and I started to think of the box of cephalosporins in our pharmacy and the prescribing rights we are privileged to have as vets. I then started to assess my own prescribing protocols and those of my colleagues. To get further insight I posted the following question on the SAMSoc discussion forum.

Do any of the members work in a setting in which there is an antibiotics prescribing protocol in place (for the moment exclude peri-operative antibiosis)?

There were numerous responses but only one centre had such a policy. So in this snap shot of one group of veterinary surgeons few had any formal prescribing protocol in place. As a result of the discussions that followed a small team of SAMSoc members started working together to produce suggestions for antibiotic choice for routine medical presentations in practice.

So why should we be responsible with antibiotic usage?Responsible antimicrobial usage in addition to infection control and hygiene measures form part of the ongoing strategy to minimize the emergence of resistant organisms. This is a concept we are all familiar with but often forget the complexities underlying it and how it should affect our antimicrobial usage.

Development of resistance occurs through mechanisms including spontaneous mutation and can be acquired by other bacteria horizontally through the transfer of genetic information (including plasmids). Some resistance mechanisms were present before the

discovery of antimicrobials, others have arisen more recently. Only when the bacterial colony is exposed to antimicrobials do these pre-existing mutations become relevant allowing the bacteria to survive treatment whilst their sensitive counterparts are eliminated.

A good example of the unintended selection of a resistant bacterial strain would be to consider the bacteria populations in the intestines when a systemic antimicrobial is prescribed for a skin infection. Within the bowel lumen, there are huge numbers of commensal organisms of both susceptible and resistant microbial strains and species. A bacterium may carry the genetic material to confer antibiotic resistance but in the absence of treatment it offers little survival advantage.

In fact typically bacteria which are sensitive to the antibiotic will flourish and out number the antimicrobial resistant strains. The prescribing of systemic antimicrobials to treat the skin infection will reduce numbers of bacteria that are sensitive to the drug within the intestinal flora. Following elimination of the competition the resistant bacteria expand in number and may predominate. Whilst the vet is observing an improvement in the skin disease having selected an appropriate antimicrobial for the skin problem, resistant organisms may have been selected for in the bowel.

Furthermore through transfer of genetic material previously sensitive bacteria may acquire the resistance trait. The longer the course of treatment persists the more profound this selection pressure and the fewer sensitive bacteria remain.

To minimize this effect the appropriate strategy would be to limit the duration of antimicrobial treatment, and use a product that has as narrow a spectrum of activity as possible. In this example an even

Guide to the guidelines

Ian Battersby, chair of SAMSoc and leader of the initiative that resulted in the SAMSoc/BSAVA Antibiotic usage guidelines, explains how and why he became interested in veterinary antibiotic prescribing practices

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PRESCRIBING

better strategy would be to restrict treatment only to the area of disease using topical therapy and thus avoiding the distant consequences.

So the old presumption that long and extended courses prevent resistance is incorrect. In fact prolonged courses eliminate bacteria that compete with the resistant strains. As such, it is important to remember that we should be prescribing antibiotics only when clinically appropriate and for as short a course as necessary in an effort to limit selection of resistant strains. When possible, topical therapy should be chosen over systemic administration.

The human hospital approachIn human medicine, the continual management and monitoring of MRSA and other multidrug resistance bacteria is an area of considerable clinical interest and public concern. All human hospitals throughout the country will have a protocol like that outlined by the consultant I met.

Similarly, on my initial visit to my local GP, when prescribing the first course of antimicrobials, the nurse practitioner had referred to a booklet outlining antibiotic choices and treatment duration for a list of common clinical conditions. This ensured that an antimicrobial was chosen which was most likely to be effective in the given clinical situation and was prescribed for the appropriate length of time. Furthermore, this protocol limited the use of certain antimicrobial groups so that they could be reserved for cases with proven resistance to the first line treatments. Another personal observation is that antibiotic courses

prescribed by doctors tend to be shorter than those often prescribed by veterinary surgeons for similar conditions.

What can vets do?As discussed above if we are honest a lot of us dont have such protocols in place in our practice. A recent survey by FECAVA of BSAVA members revealed only 36% had protocols for surgical prophylaxis and 15% for resistant infections and routine clinical cases. But by implementing protocols of responsible antibiotic usage in our clinics we can PROTECT antibiotic efficacy for our patients and also play our role in minimizing the emergence of resistant pathogens of threat to human health as well.

As veterinary surgeons in the UK, our privilege to prescribe antimicrobials has not gone unnoticed. Recently it came under the spot light in the 2008 Annual Report by Sir Liam Donaldson, the Chief Medical Officer. In this report there was a recommendation to limit the use of fluroquinolones and cephalosporins in animals due to a perceived risk of the consequences of resistance to these antimicrobials in human health. Further afield similar concerns have been raised in the European political sphere (see pages 810) and calls for a profession wide standardized approach to antimicrobial selection can not be ignored.

Professions approachIt is therefore vitally important that the veterinary profession adopts a responsible and unified approach on antimicrobial usage to demonstrate that restrictions

such as those outlined in the CMO report are not needed. The SAMSoc antibiotic prescribing initiative (PROTECT) is a step in that direction and we are grateful to the BSAVA for its assistance and support in achieving publication of the PROTECT guidelines in poster form (accompanying this issue of companion). The PROTECT guidelines have been compiled by a panel of practioners and academics, are based on the available scientific literature and reference texts and are detailed on the poster.

I would like to particularly thank the SAMSoc members who have helped with this project, Andrew Jagoe, Professor Ian Ramsey, Tom Maddox, Jon Camillari, Alison Woodward and Dr Tim Nutall, and BSAVA for facilitating the production of the poster. In the coming months a more detailed, referenced booklet, will be available online for download, see future additions of companion for more information.

Of course these PROTECT guidelines are suggestions based on current knowledge and in the future we hope they will be further refined as our experience grows. This is an evolving situation and hopefully more work will be undertaken, in particular looking at treatment durations, allowing further refinement and optimization of practice policies. The key principles are that by implementing a prescribing protocol in our practices we are treating our prescribing privileges responsibly and maximizing the efficacy of the presently available agents for the benefit of both veterinary and human patients now and in the future. n

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PRESCRIBING

Guide to the guidelines

ractice policy n A practice policy for empirical prescribing (whilst awaiting cultures) can

optimize therapy, and minimize inappropriate use of antibacterials

educe prophylaxis n Antibacterials are not a substitute for surgical asepsis n Prophylactic antibacterials are only appropriate in a few medical cases (e.g.

immunocompromised patients)

ther options n Reduce inappropriate antibacterial prescribing (e.g. due to client pressure, in

uncomplicated viral infections or self-limiting disease) by providing symptomatic relief (e.g. analgesia, cough suppressants)

n Use cytology and culture to diagnose bacterial infection correctly n Effective lavage and debridement of infected material reduces the need for

antibacterials n Using topical preparations reduces selection pressure on resistant

intestinal flora

ypes of bacteria and drugs n Consider which bacteria are likely to be involved, e.g. anaerobic/aerobic,

Gram +ve versus Gram -ve n Consider the distribution and penetration of the drug n Consider any potential side effects

mploy narrow spectrum n It is better to use narrow-spectrum antibacterials as they limit effects on

commensal bacteria n Avoid using certain antibacterials as first line agents; only use when other

agents are ineffective (ideally determined by culture and sensitivity testing)

ulture and sensitivity n Culture promptly when prolonged courses are likely to be needed

(e.g. pyoderma, otitis externa, deep/surgical wound infection) or when empirical dosing has failed

reat effectively n Treat long enough and at a sufficient dose

and then stop n Avoid underdosing n Repeat culture after long courses

Are you PROTECTing your antibacterials?

PROTECT

Follow the Cascade (www.vmd.gov.uk) Choose a drug specifically licensed for that condition in that species before considering unauthorised medication.

Topical antimicrobial preparations or even chlorhexidine preparations, when appropriate, can minimize the impact of antimicrobials in areas in which they are not needed.

Combination therapy should only be used when necessary based on knowledge of the disease and the results of culture.

Avoid empirical use of amikacin, 3rd and 4th generation cephalosporins (except cefovecin Convenia) and fluoroquinolones use these when other agents are ineffective and culture/sensitivity testing indicates that organisms are sensitive.

There are very strong arguments that antimicrobials with restricted use in human medicine (e.g. imipenem, vancomycin) should not be used in animals under any circumstances.

A basic knowledge of common pathogens implicated in infections in different parts of the body can help with selection of empirical antimicrobials. This information will follow in an online summary document.

Drug metabolism is complex, but dosage adjustments may be required, for example, in cases of hepatic insufficiency. Some drug combinations are contraindicated. The BSAVA Small Animal Formulary has simple summary tables.

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PRESCRIBING

Question 1Prevention and management of multidrug resistant bacterial infections in veterinary practice requires implementation of a number of strategies, which include (choose more than one if applicable):

A. Practice hygiene protocolB. Practice infection control protocolsC. Appropriate diagnostics to determine

if antimicrobial agents are necessary and to target therapy

D. Education of staff and clientsE. Practice prescribing protocol for

antimicrobial agentsF. All of the above

Question 2In the Chief Medical Officers Annual Report 2008, Sir Liam Donaldson recommended banning the use of two antimicrobial drug groups by vets due to a perceived risk of the contribution to bacterial resistance in human health. Pick the 2 drug groups from those listed below:

A. PenicillinsB. SulphonamidesC. CephalosporinsD. FluoroquinolonesE. MacrolidesF. Aminoglycosides

Question 3Which of the following statements is true:

A. To prevent the selection of resistant bacteria, antibacterial courses should be long. The prescription of topical medication rather than systemic antibacterials has no influence on the selection of resistant bacterial selection in other areas of the body, e.g. the bowel

B. To prevent the selection of bacterial resistant strains antimicrobial courses should be as short as possible, well targeted (based on culture) and agents chosen with as narrow a spectrum as possible. Using topical therapy (if appropriate) can prevent selection of resistant strains in non-target treatment areas.

companion | 7

Answers: 1: F; 2: C&D; 3: B; 4: A&D; 5: A,C&D; 6: E

Quick multiple choice questionsAfter reading through this issue of companion and the accompanying PROTECT poster, how many of the following can you answer correctly?

Question 4You are presented with a dog which has been prescribed a short course of a systemic fluoroquinolone for the treatment of a deep pyoderma whilst culture results are pending. The dog will need a long course of therapy to resolve its disease. Your culture yields a Staphyloccus that is sensitive to fluoroquinolones, amoxicillin/clavulanate and clindamycin. The following are all treatment options that you could instigate. Which of the following suggestions would be most appropriate based on the recommendations within the articles and poster provided in this special edition of companion? (Choose more than one if applicable.)

A. Topical therapy (e.g. chlorhexidine baths)B. Continue the same fluoroquinolone

systemicallyC. Prescribe a combination therapy of

amoxicillin/clavulanate and the fluoroquinolone

D. To help protect efficacy of fluoroquinolones, change to an antimicrobial agent of a lower tier to which the bacteria is sensitive

Question 5In which of the following conditions are antibacterial agents not indicated? (Choose more than one if applicable.)

A. Acute vomiting or diarrhoeaB. Infected traumatic woundC. Chronic diarrhoea (unless in a treatment

trial for antibiotic-responsive diarrhoea)D. Feline lower urinary tract diseaseE. Struvite urolithiasis in a dog

Question 6Empirical prescribing of second and third choice antimicrobial agents should be avoided. These agents should be used only when other agents are ineffective and culture and sensitivity testing indicates their use. Which of the following antimicrobial agents are suggested second and third choices?

A. 3rd generation cephalosporins (except cefovecin Convenia)

B. 4th generation cephalosporinsC. FluoroquinolonesD. AmikacinE. All of the above

Drug efficacy is determined by multiple factors including lipid permeability, environment of the target tissue (e.g. tissue pH, necrotic tissue or presence of a foreign body), the spectrum of activity of the drug and bacterial antibiotic resistance. No antimicrobial is stronger than another, older antimicrobials can be just as effective as the newer drugs if the organism is sensitive.

Factors that can influence activity of an antimicrobial at a target site include:

Poor blood supply (e.g. heart valves) can result in suboptimal drug levels being achieved in the target tissue

Lipid barriers prevent drug permeability to the CNS, eye, bronchial secretions, prostate and mammary glands. Severe inflammation causes the lipid barrier to be more permeable but as the inflammation resolves bacteria can sequester within the tissue unless a lipid-soluble drug is used

Weak acid drugs work better in acidic environments, and weak bases in alkaline environments (e.g. tetracyclines will be more effective in acidic urine)

Anaerobic environments (e.g. necrotic tissue) reduce aminoglycoside activity

Pus, necrotic tissue and foreign material can reduce the chances of achieving adequate tissue concentrations at the target tissue and act as a nidus of infection

Due to the high renal excretion of the beta-lactam drugs, high concentrations can be achieved in the urine, often much higher than those used in disc diffusion testing. As a consequence, in some cases of urinary tract infection beta-lactams may still be effective in the face of a resistance grading based on disc diffusion testing

Pencillins rely on bacterial division, as they act on the cell wall. So if bacterial growth is slow, due to environmental conditions or the concurrent use of bacteriostatic antibiotics, drug efficacy may be reduced

Intracellular pathogens require a drug that will penetrate into the cell rather than those that remain in the extracellular space.


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ANTIMICROBIALS

There were heart-felt, yet somewhat muted celebrations for the leaders of the veterinary profession when a european Parliament Committee rejected a proposal in April to stop practitioners selling medicines to their clients.

Senior officers of the Federation of Veterinarians of europe knew that their lobbying had been a key factor in blocking a plan that could have had damaging effects on the profitability and practicality of practices across europe. But they realised that the threat had not been killed off and, like the monster in a horror movie, it would likely come back to

the second argument. There is a widely held view in the european institutions that veterinary use of antimicrobials is contributing to the emergence of resistant bacterial strains in humans and could compromise doctors ability to treat life-threatening diseases.

Driving the debatePeter Jones, former head of the veterinary unit at the european Medicines evaluation Agency and chair of the British Veterinary Associations Medicines Group, notes that antimicrobial resistance is a hot issue in Brussels. It is the Scandinavian countries that are the driving force; they think that the veterinary profession has not done enough to tackle the issue. They are saying that it is too late for the vets, who havent taken on board the need for responsible use. Therefore, legislatationis needed to stop veterinary use of certain antimicrobials.

Indeed, the european Commissioner for Health and Consumer Policy John Dalli has warned that specific controls on antimicrobials will be considered in the review of licensing regulations for veterinary medicines due to be completed next year.

Dispensing antimicrobial drugsVeterinary practices have long accepted the need to place their stocks of potent medicines under lock and key, or risk losing them during the night. These days there is a new threat from a group that wants to clear the dispensary shelves of valuable drugs but they are Brussels-based politicians rather than criminals. John Bonner finds out what the profession needs to do if it wants to retain the right to dispense its current range of antimicrobial products

menace them before they could sleep easy in their beds.

A major reason why the Committee threw out the plan was because it conflated two entirely separate issues an economic argument against the veterinary professions supposed ability to control the medicines supply chain, and a public health argument against allowing vets to dispense antimicrobial drugs that may be needed in human medicine.

While MePs were unconvinced that removing the right to dispense any drugs was a proportionate response to the former issue, there was much more sympathy for

ANTIMICROBIALS

08-10 Antimicrobial Feature.indd 8 20/09/2011 11:24

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ANTIMICROBIALS

Dr Jones insists that it is not too late for veterinary surgeons to preserve their current armoury of antimicrobial products, but they do need to provide convincing proof that these products are being used responsibly. It may be necessary to consider formularies, written protocols defining which drugs are to be used in which circumstances, a move that has already occurred in the National Health Service. Vets wouldnt like that because the belief that you should rely on your clinical judgement is long established and runs very deep. But if the profession doesnt accept this as a wake-up call, then it is certainly going to lose some classes of drugs that are needed in practice the situation is that serious.

Restricting new medicinesAs a veterinary surgeon who spent most of his career in the field of public health, BVA Past President Bill Reilly says many medics share the view of the former Government Chief Medical Officer Liam Donaldson that the fluoroquinolones and the third/fourth-generation cephalosporins are too valuable in human medicine to be used by vets. While Professor Reilly doubts there is any scientific justification for taking away existing products, there may be one for restricting vets access to any new products. However, he warns that any future decisions on medicines availability may be driven by political rather than scientific judgements.

The overriding concern of the Scandinavians has been antimicrobial use in agriculture and the risk of food-borne transmission of resistant bacteria to consumers of animal protein. But there is no doubt that small animal practitioners will increasingly be the focus of those wishing to curtail veterinary use of the products. Bill Reilly says there is little solid evidence to identify the most important cause of resistance in enteric bacteria, but he suggests that companion animals are likely to pose far less of a threat than other humans or farm livestock. Nonetheless, it

would be foolish to discount the risk of transmission to a child cuddling a guinea pig that has been treated with a fluoroquinolone, used quite legitimately in that species, he says.

Growing concernWith epidermal pathogens like MRSA, there is even greater cause for concern as there is growing evidence that the Staphylococcal strains are much less species-specific than formerly believed, warns Tim Nuttall, senior lecturer in dermatology at Liverpool Veterinary School. If a pet animal is to pick up an MRSA or MRSP (meticillin-resistant Staphlococcus pseudointermedius) infection it is likely to be during a visit to their veterinary practice.

Less than 1 percent of normal healthy dogs carry these organisms but in dogs that are visiting veterinary practices the prevalence is much higher, 310 percent. Meanwhile, surveys have shown that between 7 and 13 percent of veterinary professionals are carriers, a much higher rate than for the typical human population, Dr Nuttall explains.

If there is MRSA and MRSP contamination of the veterinary practice environment, then that is a clear indication of inadequate hygiene standards, but are unsatisfactory prescribing practices a factor behind the growing frequency of MRSA cases in veterinary patients? Dr Nuttall fears that there may evidence to back that claim. Staff at Liverpool Veterinary School have carried out a survey looking at practitioners choices for antimicrobial therapy in particular scenarios. The results are still being analysed and will be published soon but, in essence, the study does show that a minority of practitioners are using inappropriate drugs and are even using products off label when there is an appropriate first- or second-line antibiotic available, he says.

Association adviceTo encourage responsible prescribing by all veterinary practitioners, the BVA

produced a poster setting out the basic principles and the specialist divisions are providing further guidance relevant to the particular species. In order to widen awareness, the Small Animal Medicine Society (SAMSoc) has worked closely with BSAVA to provide relevant guidelines for vets in small animal practice. This new poster is enclosed with this issue of companion and is also available to download for members online.

Ian Battersby, of Davies Veterinary Specialists and one of the main authors of the guidelines, says the poster was designed to encourage rational decision-making. We have to look at the spectrum of antibiotics that are available to us and choose the most appropriate one rather than going for the heavy-hitting product straight away. The more we use antibacterial agents, the more we will encourage resistance to develop, he said. The drug companies are no longer prioritising antimicrobial research and there may not be many new options coming on to the market so we have to protect what we have already got.

The SAMSoc/BSAVA guidance is also intended to help practitioners make the right choice in situations where they may face contradictory demands. Tim Nuttall points out that there may be situations in which the requirements of the Cascade system conflict with the principles of good prescribing practice for example, the fluoroquinolones may be the only licensed product for use in certain exotic species as there will have been no proper clinical trials in those patients with other older products.

Clinicians need to use their common sense, clinical knowledge and published efficacy, safety and MIC data in choosing the most appropriate antibiotic basically that is the lowest tier that will still get the job done, says Dr Nuttall. That preserves the higher tier drugs for when they are really needed. That is how these drugs are used in human medicine and those are the rules that the veterinary profession will be expected to follow.


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ANTIMICROBIALS

Dispensing antimicrobial drugs

He urges colleagues to make much wider use of culture and cytological analysis to ensure that the infective agent is accurately identified and appropriate treatment chosen. There should also be more frequent use of alternative administration strategies topical application of antimicrobials is a reasonable alternative to systemically administered drugs. It may often be more effective and is much less likely to encourage selection of resistant strains.

Another thing that practitioners need to change is the vocabulary they use to describe antimicrobial products. We should avoid using terms like strong or weak antimicrobials. Just because a drug is an old one, doesnt mean it is weak. It may be just as suitable as a tier 2 or 3 drug when used in the appropriate situation. The newer drugs are not necessarily more potent or stronger, what they do have is particular properties which mean we should reserve them for the situation in which they are needed, usually where there is a multidrug-resistant organism involved.

Top priorityMultidrug resistance has always been a far greater danger to human than veterinary patients. So the principles of responsible prescribing that the SAMSoc/BSAVA poster is hoping to encourage in veterinary clinics have been part of the standard procedures in NHS hospitals for many years. Furthermore experience in the human healthcare system has shown that following the rules will produce results. Rigorous attention to improved hygiene standards is a key part of that process and has led to a marked reduction in human MRSA infections over the past decade There is no reason to think that this would not be an equally successful approach in small animal practice, Professor Reilly observes.

Any recent graduate from the UK veterinary schools will be fully aware of the principles of rational prescribing contained in the poster. Those clinicians that are regular attendees at CPD events will also be reasonably well acquainted with the process, but how can we ensure that the message gets through to some of the more insular practitioners identified in the Liverpool study. Ian Battersby believes that every veterinary surgeon has a duty to ensure that the issue remains at the top of the professional agenda. It is certainly something that I mention every time that I am asked to give a presentation to colleagues.

This same rigorous approach will be necessary in the advice that practitioners give to their clients, as one of the greatest risk factors for the emergence of

3 TIeR SySTeM eMPLOyeD By DR TIM NUTTALL FOR THe SeLeCTION OF ANTIMICROBIALS FOR THe TReATMeNT OF CANINe PyODeRMAFirst-line antimicrobials: clindamycin, lincomycin, amoxicillin/clavulanate, cefadroxil, cefalexin or cefovecin (if administration or compliance is likely to be a problem)

Second-line antimicrobials: enrofloxacin, marbofloxacin, difloxacin, orbifloxacin, pradofloxacin

Third-line antimicrobials: aminoglycosides, ceftazidime, piperacillin, ticarcillin, azithromycin, clarithromycin, chloramphenicol, florphenicol, tiamphenicol, imipenem, phosphomycin, rifampin

Topical antimicrobials: chlorhexidine, silver sulfadiazine, fusidic acid, mupirocin

Notes: The routine use of tetracyclines and potentiated sulphonamides is limited by the high frequency of resistance in staphylococci. However, these drugs may be useful for MRSA and MRSP infections.

antimicrobial resistance is a failure to complete the recommended course of treatment. Small animal practitioners are unlikely to face the same problems that confront their farm practice colleagues in ensuring compliance since their clients are unlikely to encounter the same economic penalties associated with milk withdrawal periods, etc. But a clients apathy or forgetfulness could create the sort of conditions under which resistant strains may develop. In human medicine there is a tremendous amount of effort going into patient education. you see posters explaining the issues up in waiting rooms and even in train stations. It is equally vital that we get the same message across through the press and directly in our conversations with clients says Dr Nuttall. n

Vancomycin, linezolid and teicoplanin should never be used.


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CLINICAL CONUNDRUM

Clinical conundrum

Dr Tim Nuttall and Dr Ana Mafalda Lourenco Martins invite companion readers to consider a case of alopecia, crusts and pruritus in a young Great Dane

conundrum

Case presentationA 1-year-old female neutered Great Dane was presented with alopecia, crusts and pruritus. She was otherwise well. The dog was fed a balanced commercial diet and some treats, was properly vaccinated and dewormed. She lived with two other dogs, which were healthy and had lived her whole life in Portugal.

The dog had orthopaedic surgery 6 months previously. Following this, she was hospitalised for several days and received two courses of antibiotics (enrofloxacin and amoxicillin/clavulanate), although the dose and duration of treatment was unknown. Otherwise she recovered well from the surgery.

Problem list Pustules, scaling and pruritus. Mild generalised lymphadenopathy.

Which of the following conditions are most likely?1. Superficial spreading pyoderma.2. Superficial pustular dermatophytosis.

3. Pemphigus foliaceus.4. Subcorneal pustular dermatosis.5. Superficial pustular drug reaction.6. Leishmaniosis.7. Lymphoma.

What would you do next?We first performed hair plucks, skin scrapes and skin cytology to look for

Physical examinationThe dog was in good body condition and abnormalities were limited to mild generalised lymphadenopathy and skin lesions (Figure 1). There was severe erythema with pustules, papules and scaling of the ventral abdomen. There were also multifocal areas of alopecia, erythema and scaling over the dorsal trunk.

Figure 1:(A) The patient on presentation(B) Several areas of patchy alopecia can be seen in the dorsal neck region(C) Abdominal region. Note the presence of erythema, pustules and scales(D) Close-up of part (C) showing several pustules (blue arrows) not far apart and a collaret (black arrow)(E) Two large coalescing scales (collarettes)

A

C

E

B

D

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CLINICAL CONUNDRUM

Clinical conundrum

infection. Lymph node cytology and serology for Leishmania infantum was also done because of the mild lymphadenopathy and high prevalence of this disease in Portugal.

FindingsSkin cytology revealed degenerate neutrophils with intracellular cocci consistent with pyoderma caused by Staphylococcus pseudintermedius (Figure 2). Bacterial culture and antibiotic sensitivity testing were considered, but as there were no rods on cytology or recent antibiotic therapy, an empirical antibiotic choice was considered appropriate. Lymph node cytology and Leishmania serology were positive for leishmaniosis.

What are your plans for management of this case?For pyodermaAntibiotics may be empirically chosen without culture and antibiotic sensitivity testing in uncomplicated superficial skin infections without risk factors for resistance. As Staphylococcus pseudintermedius is the most frequent organism isolated in canine skin infections, the chosen antibiotics should be active

against Staphylococcus spp. Topical antimicrobials are also recommended as they will help improve the skin lesions and decrease the time to clinical resolution. We therefore started treatment with a 3% chlorhexidine shampoo twice weekly and cefalexin at 30 mg/kg po twice daily.

For leishmaniosisA pre-treatment complete blood count and biochemistry profile were unremarkable and we started treatment with allopurinol (10 mg/kg po twice daily for life) and meglumine antimonate (75 mg/kg s.c. twice daily for 4 weeks). Most animals will have a favourable response within 1 month and a significant clinical improvement by 3 months, after which a steady phase is reached.

Follow-up: 1 month after treatment Pustules have not resolved. The dog is highly pruritic.

How would you approach this case now? Either:a. Consider the possibility of drug-

resistant Leishmania infantum strains and choose an alternative protocol.

b. Continue with the same treatment and re-evaluate in a further month.

c. Repeat skin cytology.d. Perform bacterial culture and antibiotic

sensitivity testing.e. Consider new problem (e.g. drug

reaction?).

Thoughts, further investigation and new diagnostic planSkin cytology again revealed degenerate neutrophils with intracellular cocci consistent with a staphylococcal pyoderma. The leishmaniosis appeared to be under control, and resistance to

treatment is very rare. We therefore concluded that the pyoderma had not cleared despite treatment with cefalexin and chlorhexidine, suggesting an antibiotic-resistant infection. Bacterial culture and antibiotic sensitivity testing were performed. We informed the laboratory of our suspicion, and they screened for meticillin-resistant organisms by plating enrichment cultures on a selective medium. PCR was used to assess whether suspect colonies had the mecA gene, which confers resistance to beta-lactam antibiotics. Culture revealed a meticillin-resistant Staphylococcus pseudintermedius (MRSP) sensitive to amikacin, vancomycin, linezolid, cloramphenicol and quinupristin/dalfopristin only.

ManagementWe discussed the most suitable antibiotic with the microbiologists and the owners, considering efficacy, costs, adverse effects, ethical dilemmas and availability for veterinary use. We decided to start treatment with florphenicol (35 mg/kg s.c. three times daily), which should have the same activity as chloramphenicol. Unlike chloramphenicol, florphenicol is approved for use in animals (in cattle for respiratory infections) and is not associated with aplastic anaemia. Reported adverse effects include injection site pain, anorexia and decreased water intake. We continued twice weekly bathing with 3% chlorhexidine, but this was done in our veterinary hospital by trained staff to improve efficacy and reduce potential zoonotic risks.

What should we tell owners about transmission to humans?1. MRSP is potentially a zoonotic

pathogen but transmission to humans is less common than MRSA.

Figure 2: Neutrophils with intracellular coccoid bacteria (black arrows)


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CLINICAL CONUNDRUM

2. Zoonotic staphylococcal infections are rare.

3. Groups at risks for zoonotic infection include owners with open wounds, that are immunocompromised or undergoing surgery.

4. Owners should contact their doctor if they have any doubt or worries.

5. The Worms and Germs blog is very useful for owners (www.wormsandgermsblog.com).

Follow-upThe dog started to improve after implementation of the new antimicrobial treatment protocol (Figure 3). Complete clinical resolution took 3 months, and treatment was then continued for a further 14 days. The dog has been in complete remission and has not received any medication except allopurinol for 6 months. The other two dogs in the household remained healthy throughout and there was no evidence of zoonotic transmission to the owners or veterinary staff.

DiscussionMost veterinary practitioners are used to treating staphylococcal pyodermas, as these are common in general practice. Nevertheless, clinicians should be aware of

meticillin-resistant staphylococci. MRSA and MRSP infections are much less common than antibiotic-sensitive infections but the prevalence appears to be increasing. This is of great concern because of the therapeutic challenge, risks for contamination of veterinary premises and zoonotic potential. In particular, MRSP infections often have a very restricted range of antibiotic sensitivity.

Figure 3: The patients lesions have gradually improved after 3 weeks of florphenicol

The zoonotic potential of MRSP infections (Figure 4) scares owners, and there are ethical dilemmas for clinicians, including whether or not to use antibiotics with adverse effects (e.g. chloramphenicol and aminoglycosides) or those that are important for human health (e.g. vancomycin and linezolid). Currently, the absence of guidelines for the diagnosis and treatment of multidrug resistant

MRSP

MRSA

Courses of antibioticMeticillin-resistant bacteria

Resistant bacteria/gene transfer

Figure 4: Schematic drawing showing the most important direction for the transmission of MRSP (blue) and MRSA (pink), both of which are potentially zoonotic diseases


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CLINICAL CONUNDRUM

Clinical conundrum

infections leaves the choice of antimicrobial to the practitioner. It is therefore important that you are prepared to deal with these cases. Discussing cases with your microbiologists can be very helpful, and you may need to refer the case for specialist care and treatment.

Empirical antimicrobials can be appropriate for first-line treatment of staphylococcal pyodermas, as most isolates have a relatively predictable sensitivity pattern. Clindamycin, cephalosporins and amoxicillin/clavulanate are suitable provided that it is a surface or superficial infection, cytology is consistent with a staphylococcal infection, it is the first treatment and there are no risk factors for resistance.

Culture and antibiotic sensitivity testing, however, should be performed for deep pyodermas, if rods are seen on cytology, after multiple antibiotic courses, after treatment failure and if there are risk factors for resistance. In hindsight, the surgery and antibiotic treatment 6 months earlier should have alerted us to the possibility of antibiotic resistance in our case, and we should have taken samples for culture from the dog on the first visit. Antibiotics to treat resistant infections should be chosen based on the results of culture and antibiotic sensitivity testing.

Topical therapy is often useful as the high local concentrations that are achieved can overcome some resistance. For example, 9 out of 10 cases of MRSP infections in dogs in a recent report were cured following treatment with topical fusidic acid, even though in vitro sensitivity testing revealed resistance to fusidic acid. In this case we elected to use systemic treatment because the extent and nature of the lesions were not suitable for topical antibiotic therapy alone. We also used chlorhexidine, as recent studies have shown that this is highly effective against

MRSP; 5 out of 8 dogs with MRSP infections were cured or substantially improved following treatment with a 2% chlorhexidine shampoo. Compliance can be a problem with topical treatment, and we therefore used trained staff to ensure proper application and improve efficacy. Treatment should be continued to complete clinical resolution and beyond if it is possible that sequestered bacteria may survive (e.g. deep pyoderma, orthopaedic infections, etc.).

Why do these resistant infections occur? Risk factors in dogs have been poorly investigated, but things to watch out for include (Figure 5): previous antimicrobial therapy, particularly with fluoroquinolones and/or beta-lactams; frequent antimicrobial use; recurrent infections; prolonged hospitalisation; postoperative or nosocomial infections; and non-healing wounds.

Responsible antibiotic use will be important in preserving the clinical efficacy of these drugs. Antibiotics should not be used unless an infection has been confirmed, and bacterial cultures should be performed more frequently. We should also question whether the patient really needs systemic antibiotics, or whether topical antimicrobials and antibiotics would be more suitable. It is also vital to communicate the importance of treatment to owners in order to improve compliance, reduce therapeutic failure and decrease the risks of resistance.

AffiliationDr Tim Nuttall is Senior Lecturer in Veterinary Dermatology, The University of Liverpool School of Veterinary Science, and Dr Ana Mafalda Lourenco Martins is Lecturer in Veterinary Dermatology, The University of Lisbon Faculty of Veterinary Medicine.

Figure 5: Number and nature of known risk factors for MRSA/MRSP in this patientAMX = amoxycillin clavulanmic acid; ENR = enrofloxacin

Antibiotic historyAntibiotic therapy More than two courses Beta-lactam antibiotics AMXFluoroquinolones ENRMedical historyNo. of visits to the vet

Admitted Surgery IV catheterization Infection historyOnset

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HOW TO

How to

For this special edition of companion Jonathan Bray, Senior Lecturer in Small Animal Surgery at Massey University, New Zealand, describes the rational use of antibiotics in surgical patients

Use antibiotics in surgical patients

The skin and mucosal surfaces provide an important barrier to bacterial colonisation of the underlying tissues. When these barriers are penetrated as part of a surgical intervention, there is a risk of developing an infection.

Although surgical site infections are rarely a cause of death, they can contribute to a delayed surgical recovery, increased morbidity or debilitation, or cause catastrophic failure of a repaired wound or fracture. Surgical site infections are inevitably associated with increased costs both financial and emotive and surgeons obviously strive to do all they can to prevent an infection from developing.

The role of antibiotics in preventing infection following surgery has been recognised from the 1950s. Since that time, there has been an enormous amount of research, comment and opinion published that has advanced our understanding surrounding the perioperative use of antibiotics.

When considering the role of antibiotics in the perioperative period, it is important to recognise the distinction between prophylactic and empirical antibiotic therapy. The goal of prophylaxis is to reduce the incidence of postoperative wound infection, and assumes use where contamination might occur, but has not yet happened. Empirical therapy is the continued use of antibiotics after the operative procedure based upon the intraoperative findings (e.g. leakage of a viscus). Inappropriate prophylaxis is characterised by the unnecessary use of broad-spectrum agents and continuation of therapy beyond the recommended time period. These practices increase the risk of adverse effects and promote the emergence of resistant organisms.

Why all the fuss about antibiotics?There is no question that antibiotics are effective in preventing development of an infection following surgery. A meta-analysis of 26 other meta-analysis studies strongly supported the hypothesis that antibiotic prophylaxis was an effective intervention for preventing surgical site infection over a broad range of surgical procedures.

However, administration of antibiotics increases the prevalence of antibiotic-resistant bacteria causing infection. It is well accepted that increased antibiotic

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HOW TO


use leads to the development of more resistance. In human surgery over the last 10 years, an increasing number of resistant pathogens, such as meticillin-resistant Staphylococcus aureus (MRSA) and Candida species, and infection with organisms such as Clostridium difficile (a cause of antibiotic-associated colitis), have been commonly implicated in surgical wound infections. Such developments have forced a tougher evaluation of antibiotic usage, and a strict adherence to national guidelines.

Good data on the incidence of surgical site infection is not available for the veterinary profession. However, there is no reason to believe that we should be immune to similar trends. Reported cases of MRSA infection in domestic animals have been increasing, particularly in orthopaedic procedures where surgical implants are used. This suggests that veterinary patients are not immune to the changes in antibacterial resistance of bacterial flora that are occurring in the population.

Although an individual veterinarian may believe their own hospital policies are unlikely to make a significant impact on the global trend of antibiotic resistance, there is good evidence to suggest that inappropriate use of perioperative antibiotics may increase the risk of surgical site infection with more difficult opportunistic organisms. This is because surgical site infections typically develop due to colonisation of the wound with bacteria arising from either the patients own endemic flora or from the human staff involved in its care.

In one recent study, 2 out of 10 staff in a veterinary orthopaedic referral hospital were found to be positive for nasal colonisation with MRSA, and a higher rate of MRSA-associated wound complications was identified in cases managed by one surgeon who was consistently positive for nasal MRSA during the study period. It must now be assumed that animals coming into a veterinary hospital for surgery will also be carriers of opportunistic bacteria they have acquired from their own environment.

The prevalence of antibiotic-resistant bacteria in any population is related to the proportion of the population that receives antibiotics, and the total antibiotic exposure. Therefore, as the trend for increasing rates of antibiotic resistance in all human hospitals rises, so to does the likelihood that staff and animals will be carriers of antibiotic-resistant organisms.

This trend is important as it has been shown that if antibiotic usage following routine surgery is prolonged, selection for these resistant organisms may lead to infection. In a small study comparing short term (24 hour) with longer term (five day) prophylaxis following excision of head and neck lesions, significantly fewer patients in the short term group

developed wounds infected with MRSA (4/33 compared with those treated long term (13/31, p=0.01).

Historical perspectivesThe principles of antibiotic prophylaxis were founded from several key experiments performed in the 1950s and 60s. Although these experiments may seem unsophisticated by todays standards, they continue to give a valuable insight into the interaction between the host tissues and bacteria, and the role of antibiotics.

In 1957, Miles et al. defined what they termed a decisive period, which represented an intense period of activity between the host defense mechanisms and the bacteria. These defense systems which we now know to represent opsonin proteins and other non-specific neutralisers of bacterial activity act immediately when bacteria are introduced into normal tissue. These tissue defenses are capable of decreasing the infectivity of contaminating bacteria, thus lowering or eliminating the potential for visibly evident inflammation or for infection to develop.

Miles et al. (1957) also demonstrated that the ultimate size of a lesion was determined by the effectiveness of the antibacterial reactions mustered by the tissues during this period. Crucially, they were able to demonstrate that the duration of this decisive period was brief lasting for just 23 hours after bacterial inoculation. Changes to the host defenses after this period had no impact on outcome; in essence, the battle between bacteria and host had been decided within these first few hours of bacterial contamination.

Miles et al. concluded that because this decisive period was predictively short, the point at which preventive antibiotic supplementation may be stopped after surgery could also be accurately determined assuming there was no ongoing contamination.

In 1961, Dr John Burke published the results of an important study that addressed many fundamental issues of wound infection and antibiotic usage. In this

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HOW TO

study, he created similar sized incisional wounds on animals, and inoculated each wound with the same quantity of bacteria known to induce an infection. The wound was then closed. Dogs were grouped according to the timing of administration of the antibiotic.

In Group 1, dogs were given an intravenous antibiotic 1 hour before the wound was created and bacterial inoculation performed. In Group 2, dogs were given the antibiotic at the same time as the wound was created and bacteria inoculation occurred. In Group 3, dogs were given the antibiotic after wound creation, bacterial inoculation and wound closure had occurred. In the final Control Group, no antibiotics were given at all.

Crucially, none of the dogs in Group 1 developed a wound infection, whereas dogs in both Groups 2 and 3 developed an infected lesion that was roughly of similar size and extent as the Control Group. This simple experiment reaffirmed the observations of Miles et al., and demonstrated the importance of antibiotic being in the circulation when contamination of the wound occurred.

In a second phase of Burkes experiment, the treatment of Group 1 dogs was expanded to include two new groups. In Group A, just a single preoperative intravenous antibiotic was given. In Group B, antibiotics were continued for 5 days after surgery. In this study, there was no difference in infection rates between the two groups, indicating that continued courses of antibiotic were unnecessary if no further contamination of the wound occurred. This experiment, again, reaffirmed Miles et al. observation of a time-dependant decisive period.

Based on his experiments and understanding, Burke was able to make the following pertinent observations, which remain relevant today:

1. The effectiveness of defense against bacteria depends largely on host resistance.

2. Host resistance is reduced by the abnormal physiology induced by anesthesia and surgery.

3. The risk of infection can be reduced, or prevented, by supplementing the hosts antibacterial resistance, but only if the supplement is delivered before bacterial contamination of the tissue has occurred.

4. Supplements to host resistance serve no purpose if they are delivered for periods longer than four hours after the end of the period of active bacterial contamination of tissue.

5. Preventive antibiotic supplement is reasonable only if the risk of infection or infectious morbidity or mortality is clearly greater than the risk of side effects to the preventative antibiotic.

Reducing the need for antibioticsIt is often quoted that infection will develop if more than 106 bacteria per gram of tissue are present. However, the number of bacteria required to produce infection in guinea pig muscle will be reduced 1,000-fold if the muscle has been crushed. Even fewer bacteria are required if foreign material is also introduced. Thus, the surgeons technical skill is also a key factor in whether contaminating bacteria are able to gain the upper hand against tissue defenses, and allow an infection to develop.

When considering the causes of infection, Louis Pasteur recognized the importance of factors other than the mere presence of bacteria when he observed that the germ is nothing: it is the terrain in which it grows which is everything. In human medicine, it is known that infection rates can vary from surgeon to surgeon, from hospital to hospital, from one surgical procedure to another and most importantly from one patient to another. Clearly, development of a wound infection involves an interplay between host factors, the wound environment and the virulence (and quantity) of bacteria contaminating the wound.

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Bacterial contamination of a surgical wound is more likely to arise from the patients own flora; however, the surgeon and the surgical environment (including instruments) are also possible sources. Many of the rituals of surgical preparation are directed at reducing the potential for bacterial contamination of the open wound. Such rituals include:

1. Preparation of the patient by clipping fur around the surgical site and using antiseptic washes to remove oil, organic debris and to reduce the numbers of transient and resident bacteria.

2. The use of dedicated surgical attire for the surgeon (including scrubs, hats, mask), and similar decontamination of the surgeons hands using antiseptic washes and surgical gloves.

3. Sterilisation of instruments.4. Utilising drapes and other barriers to isolate the

surgical wound from the unprepared areas of the animal and surgical table.

In human surgery, such routines are universally accepted as a minimum standard of care in the operating theatre. However, there is good evidence that the veterinary profession in the UK has a low level of implementation of such accepted practices. In a recent survey of first-opinion practices, sterile surgical gloves were utilised in just 37.5% of practices, with gowns, masks and facemasks being worn in just 14.3%, 12.5% and 10.7% of practices, respectively.

In a separate study, practices were evaluated on their use of different skin preparation techniques. This study found that 79% of practices were unaware of the concentration of scrub preparation being used, or the contact time necessary between the antiseptic and skin during surgical preparation. In some cases, the concentration of antiseptic being used may actually have been too low to be effective at killing bacteria. Twelve percent of practices used chlorhexidine gluconate and povidoneiodine together to prepare the skin; however, these two agents are incompatible and the combination effectively provides limited or no skin asepsis.

Veterinarians may be unwilling to buy into the entire gamut of surgical rituals for a variety of reasons: financial costs are likely to be uppermost, but others may cite the lack of evidence for an individual item to lower infection rates. However, the collective value of dedicated surgical attire and sterile barriers such as gloves, gowns and drapes in lowering wound contamination rates is well accepted, and will continue to represent best practice in human and veterinary hospitals. The concern is that anecdotal evidence suggests that veterinarians tend to rely on ad hoc administration of antibiotics to mask poor practice.

Guidelines for antibiotic useSurgical site infection is by no means an inevitability of surgery. Therefore, the routine administration of antibiotics for every surgical intervention in the hope of eliminating infection is shortsighted. The surgeon must weigh up the likelihood of encountering contamination during the surgery, or whether the surgical wound is likely to favour the perpetuation of bacteria (e.g. because of the use of implants). In those instances, the use of prophylactic antibiotics may be justified.

From these experiments, and the results of further clinical studies, guidelines for the use of antibiotic prophylaxis have been established. These include:

Prophylactic antibiotics should be administered within 1 hour prior to incisionBased on the work of Miles et al. and Burke, we know that for antibiotics to be effective, therapeutic tissue levels must be present within the first hour or two of wounding to supplement the tissue defenses during the decisive period. This is best


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HOW TO

achieved by the use of an intravenous preparation; the diffusion gradient created by the higher peak plasma concentration allows antibiotic levels in the tissue to be more predictable. If subcutaneous preparations are used, it becomes more difficult to determine when tissue levels are likely to be adequate, as a range of factors can influence antibiotic absorption from the injection site. However, it may be assumed that injection of a subcutaneous antibiotic at the time of surgery will fail to meet the objectives of prophylaxis as illustrated by Miles et al. and Burke.

A single preoperative dose of antibiotic is as effective as a 5-day course of postoperative therapy assuming an uncomplicated procedureBurkes work (and others) has clearly shown that a single course of antibiotic provides adequate protection from the contamination that occurs during routine surgery provided that any contamination was not excessive (e.g. spilled viscus). When contamination does occur, continuation of a therapeutic course of antibiotics is then appropriate. In all other instances, once surgery has finished and no further contamination of the wound is expected, antibiotics can safely be stopped.

During prolonged procedures, antibiotic prophylaxis should be re-administered every 23 hoursThe duration of surgery directly affects the number of bacteria that can gain access to the wound. For every hour of surgical time, the infection rate can double. To maintain tissue levels of antibiotic during the operative period, repeated intravenous administration is recommended every 23 hours.

Prophylactic antibiotics should target the anticipated organismsIn human surgery, there has been little change in the incidence and distribution of pathogens isolated from surgical site infections during the last decade. The predominant skin bacteria are staphylococci, streptococci and corynebacteria, with Gram-negative enteric bacteria present around the caudal aspect of the body. In most instances, therefore, coverage with a cephalosporin or clavulanate-potentiated amoxicillin is appropriate for this bacterial spectrum. When entering the GI tract, the potential for exposure to other organisms will increase, and supplements to this standard protocol may be required. The colon and distal small intestine will

contain an enormous reservoir of facultative and anaerobic bacteria, so antibiotics targeted at these organisms would be appropriate for surgical procedures including these organs.

Changing practice policiesIt is likely that many surgeons and veterinary practices will have a practice of antibiotic administration that is founded on custom, unsupported beliefs or adherence to dogma. However, many surgical procedures performed in general practice do not meet the guidelines whereby prophylactic antibiotics would be considered necessary. In brief, this includes surgeries that are of short-duration, elective procedures performed on systemically healthy individuals; and those procedurs where no contaminated viscus is going to be penetrated. Such procedures include elective neutering, simple lumpectomies and other minor surgical interventions. In most other instances, a single-dose of intravenous antibiotic (a cephalosporin or clavulanate-potentiated amoxicillin) given in the immediate preoperative period is safe, and in accordance with international practice.

Changing hospital practices can be difficult to achieve as the anxiety regarding infection often subjugates any desire to reduce a reliance on antibiotics. However, if this article has made you question your existing procedures, then it has fulfilled its brief. The next step requires a commitment to change. You may choose to do this as a clinical trial to randomise the administration of a new antibiotic protocol to patients, and monitor wounds closely for signs of infection. If you have confidence in your perioperative routines, surgical site infection should be evident in no higher than 2.54.8% of patients. The ideal would be to achieve this standard of care without masking poor clinical practice with antibiotics.

Selected references available online at www.bsava.com/companion

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PUBLICATIONS

The fundamentals of surgery

At a meeting of the Publications Committee, a gap in the market for a Manual covering the fundamentals of surgery was identified. It was noted that these principles often dictate the outcome of a surgical procedure, more so than the use of the most up-to-date techniques, and that a Manual providing a solid grounding in the basic principles with practical examples of why these principles are important would be a useful addition to the BSAVA range.

Under the editorial guidance of Stephen Baines, Vicky Lipscomb and Tim Hutchinson, the BSAVA Manual of Canine and Feline Surgical Principles provides information on those topics that are key to surgical success, including:

Surgical facilities and equipment (covering design, sterilization, suture materials and stapling devices)

Perioperative considerations for the surgical patient (such as preoperative assessment and stabilization, fluid therapy, sepsis, postoperative management, analgesia and nutrition)

Surgical biology and surgical techniques (including aseptic technique, wound healing, antimicrobial prophylaxis, operative technique principles and suture patterns).

Getting startedFor managers setting up new surgical facilities in their practice, this Manual offers information on theatre design (Figure 1), and the equipment and personnel required. This chapter has been written by Terry Emerson who has many years of practical experience to share following the successful establishment of two veterinary surgical facilities during his career.

Surgical instrumentsNick Bacon, a specialist in small animal surgery, provides an invaluable guide to surgical equipment that does not just

Figure 1: General view of an operating theatre. Note the PVC-lined walls and coved flooring

Figure 2: Doyen bowel clamps helping to appose the jejunum and ascending colon during anastomosis, following an intestinal resection for a large ileocaecocolic mass

Karla Lee, who was instrumental in the development of the newest addition to the Foundation Manual series, introduces companion readers to the BSAVA Manual of Canine and Feline Surgical Principles

contain lists of instruments, but a well-illustrated review of the appliances seen in veterinary surgical kits and, most importantly, when and how to use them to minimise surgical trauma and improve surgical technique (Figure 2). This information is complemented by top tips on surgical technique to reduce complications, written by a panel of specialists. These tips range from the simple to the complex: the use of stay sutures to reduce damage to delicate tissues, the use of surgical staplers in gastrointestinal surgery, and the emerging use of surgical lasers in veterinary practice.

Preoperative and postoperative managementCentral to this Manual are guidelines for the preoperative and postoperative management of the surgical patient: key aspects to a successful surgical outcome. With chapters written by critical care specialists, Karen Humm and Sophie Adamantos, as well as leading veterinary nutritionist, Dan Chan, the BSAVA Manual of Canine and Feline Surgical Principles includes advice for preoperative stabilisation of the emergency surgical patient and postoperative feeding (Figure 3).

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PUBLICATIONS

NEW FOR 2012The investigation and treatment of many recurrent skin diseases, including MRSA, are covered in the new edition of the BSAVA Manual of Canine and Feline Dermatology.

For further information and to register your interest in this title, please visit the Forthcoming titles page in the Publications section at www.bsava.com.

Figure 3: Coaxing a cat to eat by hand-feeding

Clinical case: JasperHistoryA 4-year-old DSH cat presented with a 3-month history of severe pruritus. He responded poorly to injected methylprednisolone acetate and was not on any routine flea control.

Examination and diagnosisAt presentation there were extensive areas of alopecia and excoriations on the neck and a unilateral indolent ulcer. Cytology of samples from the affected area showed numerous cocci and degenerate neutrophils. Coat brushings and skin scrapings were negative for parasites.

TreatmentJasper was prescribed amoxicillin/clavulanate at a rate of 20 mg/kg orally q12h and a selamectin spot-on treatment. The household was also treated with an insect growth regulator (S-methoprene). At the follow-up examination 3 weeks later, there was little improvement and

cocci were still evident on cytology. A swab from the affected skin was submitted for culture meticillin-resistant Staphylococcus aureus (MRSA) was isolated. Subsequent investigation revealed that the owners relative had recently undergone surgery and contracted MRSA.

Topical fusidic acid and systemic doxycycline were recommended. The owner was instructed to apply the topical preparation whilst wearing gloves, and to wash their hands thoroughly after touching the cat. Jasper made an unremarkable recovery and was subsequently investigated for underlying allergic skin diseases. A limited antigen diet trial was initiated.

ConclusionIn this case it was suspected that Jasper contracted MRSA from the owners relative; although, this could only have been confirmed by proving the strains to be identical on culture and sensitivity testing. Often people or animals who come into contact with a person infected with MRSA have a transient carriage of the organism but an infection is not usually established. Jasper may have developed the infection due to his underlying severely pruritic skin disease and previous glucocorticoid therapy.

If a resistant infection is suspected, rapid identification and appropriate treatment should be instituted and the owners counselled regarding appropriate hygiene measures. A full discussion of the management of MRSA in a veterinary practice can be found on the BSAVA website (www.bsava.com/Advice/MRSA)

Recurrent skin diseases in companion animals can be challenging to manage. Here, Hilary Jackson and Rosanna Marsella, editors of the new BSAVA Manual of Canine and Feline Dermatology, take us through a case

PUBLICATIONS

MRSA: a zoonotic infection

Controlling infectionsFor nurses responsible for the management of operating theatres and kennels, this Manual offers pointers to the successful reduction in surgical infection rates. Tim Hutchinson, with experience of a busy mixed private practice, provides practical advice on the key aspects of achieving a high level of surgical asepsis, whilst Anette Loeffler provides a useful summary on the control of hospital-acquired infections. Having spent 3 years assessing the prevalence of MRSA amongst pets and staff in a busy small animal referral hospital, Anette is one of the leading specialists in this area and is able to offer practical guidelines to this very emotive subject.

The BSAVA Manual of Canine and Feline Surgical Principles provides information relevant to all members of the practice team, and I am sure will be a must-read for vets studying for the RCVS certificate in advanced veterinary surgery, nurses with an interest in surgery and practice management. Well done to the editorial team!

For further information and to register your interest in this title, visit www.bsava.com

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PETSAVERS

Improving the health of the nations pets

How you can helpSome ideas for raising money for Petsavers in practice

Petsavers is the charitable division of the BSAVA and exists to improve our understanding and treatment of the diseases affecting out pets. Your practice can get involved by helping Petsavers to raise enough money to fund this important research. Heres how

Spread the wordMany of your clients will want to donate to a charity that aims to improve our understanding and treatment of the conditions and diseases that affect their pets. Your practice can help us to help their pets by spreading the word and letting your clients know who we are and what we do. An easy way to do this is to hold Petsavers information leaflets in your practice reception. Petsavers also produce A3 information posters for display on your practice wall. If you would like to display our leaflets or posters, please contact us and we can supply them free of charge.

Petsavers Christmas cardsEach year Petsavers sells a variety of different Christmas cards at a superb price of 3 for a pack of ten (inclusive of postage and VAT). Included in this edition of companion is an order form for Petsavers Christmas cards. The cards can also be ordered through www.petsavers.org.uk where you can see the extended range of Petsavers Christmas cards. If you work in practice and would like to make these available to your clients we can send order forms to you to display in your reception.

Displaying a collection boxCollections boxes are a valuable source of income for Petsavers. If you would like to have a Petsavers collection box in your reception area, then please get in touch.

Contact usWe are always looking for new and innovative ways of fundraising, so if you have an idea then please feel free to share this with us. Petsavers can be reached by:

Email: [email protected]: 01452 726723Post: Woodrow House, 1 Telford Way, Waterwells Business Park,

Quedgeley, Gloucester GL2 2AB.

New facesA welcome to our new Petsavers co-ordinator

We are pleased to announce that we have recently appointed a new full-time co-ordinator for Petsavers. Gemma White began the role in July 2011 having completed a degree in Public Relations at the University of Gloucestershire and previously working as an activities co-ordinator for the University.

She says, I am really excited and honoured to be taking on Petsavers. The future is looking really exciting, and I want to progress and move forward with Petsavers to ensure that we continue to raise money to fund vital research into the diseases and illnesses that affect our nations pets. I am looking forward to introducing new ways of fundraising, which I have experience in through previous job roles, and continuing to raise the profile of the Petsavers beyond the veterinary community. I am also looking forward to working closely with the committee members who continue to fully support the running of the charity.

Gemma will be on the Petsavers stand on the BSAVA Balcony at Congress 2012 and is looking forward to meeting you all there. Why not introduce yourself and find out what she has planned for the future for Petsavers. You can also keep up to date with current Petsavers activity by visiting our website at www.petsavers.org.uk.

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Stress is an underlying factor in most behavioural problems in cats, as well as in some chronic or recurrent medical problems such as feline interstitial cystitis and feline hyperaesthesia syndrome. The treatment of feline behavioural problems often fails because treatment programmes do not address this important issue.

Stress toolsJon Bowen will present a course in December that will provide clinicians not only with an understanding of stress and its effects on behaviour, but also with a set of tools for evaluating stress and minimising its impact.

The programme starts with a discussion of stress responses, and stress in the cat. It then provides an overview of drug therapies, indoor elimination, spraying and inter-cat conflict with case examples and an opportunity for case discussion.

Delegates will be given detailed notes and a set of questionnaires and handouts that make the evaluation and treatment of behavioural problems easier for the general practitioner.

By the end of the course, attendants will be able to:

Evaluate signs and causes of stress in cats Identify the causes of common behavioural

problems Plan environmental modification programmes to

minimise the impact of stress on cats Plan treatment programmes for behavioural

problems and to minimise stress.

Who the course is forVeterinary surgeons who have an interest in behaviour and would like to offer behavioural services to their cat-owning clients will benefit especially from this course. It is pitched at an intermediate level, and delegates who already tackle feline behavioural

Speaker: Jon BowenDate: Thursday 1 December 2011Venue: Holiday Inn, Gatwick AirportFees: BSAVA member 218.00 Non-member 327.00

cases will find that the course offers additional insights that will enable them to improve their success with these cases. It is also of relevance to those who do not wish to take on behavioural cases, but would like to have a more detailed understanding of stress, in recognition of its importance in clinical situations.

You will learn about the wealth of information which can be gained from examining the blood film and will also gain a greater understanding of the information your analyser generates.

The speaker, Jon Bowen has years of experience in behavioural medicine and has a good grasp of the practical issues facing clinicians who deal with behavioural problems in general practice.

Feline stressA December course with Jon Bowen exploring the basis of elimination, spraying and inter-cat conflict problems

ABOUT THE SPEAKER

Jon Bowen BVetMed DipCABC MRCVS

Jon graduated from the RVC in 1992. He runs the behavioural medicine referral service at the RVC and is a regular speaker at national meetings, such as BSAVA Congress, and at international meetings. He is the author of chapters in several books, including the BSAVA Manual of Canine and Feline Behavioural Medicine and 100 Top Consultations. He is the co-author of Behavioural Problems in Small Animals.

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COURSE INFO

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Congress 1215 April 2012

Know your enemy is a policy that makes as much sense for a veterinary surgeon in small animal practice as it does for a battlefield commander.

Vets need to know what they are up against whenever a sick animal enters their consulting room with clinical signs that could indicate a bacterial infection. However, taking a sample for bacterial culture takes time and so there is always a temptation to begin antimicrobial therapy with a broad-spectrum agent before the results come back from the laboratory.

a word of cautionThe advice at BsAVA Congress in April 2012 will be to pause before reaching for the bottle on the dispensary shelf. leading veterinary pharmacologist Dr lauren Trepanier will say that regular empirical use of antimicrobial drugs not only increases the risks of producing resistant bacterial strains, it is also bad practice increasing costs for the client without necessarily improving the prospects for a swift return to good health for their animal.

Dr Trepanier, professor of internal medicine at the University of Wisconsin veterinary school, will explain that there are situations when antimicrobial therapy makes no sense because there is no bacterial infection present. Clients may

expect their vet to provide such a course of treatment for their kitten when it is showing signs of respiratory disease, but in most cases the infection will be of viral origin and so will be unresponsive to standard antimicrobial treatments.

Infection detectionThere are other, less obvious situations where we should weigh up the likelihood that antimicrobial treatment will have no positive imp

Companion October2011

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