Evaluation of Subgingival Bacteria in the Dog andSusceptibility to Commonly Used AntibioticsMirko Radice, DVM; Piera Anna Martino, DBSc, PhD; Alexander M. Reiter, Dip! Tzt, Dr med vet

Summary:

The aim of the present investigation was to ex'aluate thesubgingival aerobic and anaerobic flora of 13 dogs withperiodontal disease and the susceptibility of these bacteriato antibiotics currently approved in Italy for ti-eatment ofcanine infections. Of the anaerobic bacteria, Bacteroidesfragilis was most frequently isolated, followed byPeptostreptococciis + Porphyromonas gingivaUs andPrevotella intermedia. Ofthe aerobic bacteria, a-hemolyticStreptococcus was most frequently isolated, ofien associatedwith Escherichia coli or Pctsteurella multocida. Resistanceof anaerobic and aerobic bacteria to various antibiotics wasgenerally high. Anaerobic bacteria appeared to besusceptible to amoxicillin + clavulanic acid, doxycycline,and erythromycin; aerobic bacteria appeared to besusceptible to amoxicillin + clavulanic acid, erythromycin,gentamycin, and sulfa-trimethoprim. Bacteroides fragiliswas resistant to all of the antibiotics tested. The emergingworldwide problem of bacterial resistance to antibioticsresulting from overuse and misuse of antibiotics isdiscussed J Vet Dent 23 (4); 219 - 224,2006

IntroductionPeriodontal disease is an infectious condition of the tooth

supporting tissues (gingiva, periodontal ligament,, alveolar bone,and cementum) and is considered to be the most common diseasein companion animals. The accumulation of plaque on toothsurfaces is responsible for tiie development of gingivitis andperiodontitis.'

Gingivitis is inflammation ofthe gingiva and is reversible, ifplaque is removed by home or professional oral hygieneprocedures.^ In addition to toxins and tissue-destructive enzymesproduced by periodontopathogenic bacteria, the host's response toplaque leads to the release of agents from damaged neutrophilsthat can cause injury to the body's own tissues.' hiflammationmay spread along the periodontal space and ultimately progressesto periodontitis, which is diagnosed as loss of attachment(gingival recession, résorption of alveolar bone, and formation ofperiodontal pockets). The periapical region ofthe tooth root maybecome affected, leading to retrograde pulpal infection. Thus,endodontic disease can occur as a result of severe periodontaldisease. Eventually the tooth becomes mobile and is lost due tospontaneous exfoliation or professional extraction.'

Gingivitis and periodontitis are referred to as 'bacterialinfections', but several hundred bacterial species have beenidentified to date in normal and diseased mouths of cats and

' With maturation of plaque in subgingival areas and

progression from a healthy periodontium to gingivitis andperiodontitis, there is a shift from a gram-positive oriented,aerobic facultative flora to a predominantly gram-negative,anaerobic flora." Periodontopathogens are bacteria that causegingivitis and periodontitis. A catalase-positive form ofthe gramnegative Porphyromonas gingivaUs is considered to be the keyperiodontopathogen in cats and dogs''-''-- and is recognized as Pgiilae.-'' Other canine and feline Porphyromonas organismsinclude P. assacharolytica, P. cangingivalis, P canoris, P. cansulci,P. endodontalis, P. circumdentaria, P. crevioricanis, P. salivosa.. P.denticanis, and P. gingivicanis."'''-" Additional black-pigmentedanaerobic bacteria associated with periodonta! disease includePre\'Otella intennedia--' and Bacteroides spp."'"-''" Pathogen-related oral spirochetes also are considered to play an importantrole in periodontal disease, but cultivation studies in cats and dogshave only been reported sparsely.*"'-'̂

Previous studies showed that amoxicillin + clavulanic acidand clindamycin had high in vitro susceptibility against anaerobesand enrofloxacin high in vitiv susceptibility against aerobes fromsubgingival plaque samples in cats and dogs,'"'' Althoughperiodontal disease is caused by bacteria, antibiotic therapy shouldnot be the primary treatment strategy,'* -̂"' Unfortunately, there is atendency among veterinarians to use antibiotics as part of themanagement of any animal with periodontal disease or other oralcondition. Resistance of plaque bacteria to antibiotics has clearlybeen demonstrated in humans,** '̂ and a similar pattern of bacterialresistance development may be present in cats and dogs.

The aim of the present investigation was to evaluate thesubgingival flora (aerobic and anaerobic bacteria) of dogs withperiodontal disease and the susceptibility of these bacteria toantibiotics currently approved in Italy for treatment of canineinfections. Furthermore, the emerging problem of bacterialresistance to antibiotics in human and veterinary medicine isreviewed.

Materials and MethodsThirteen chent-owned dogs with various degrees of

periodontal disease (ranging from gingivitis to periodontitis asassessed by means of periodontal probing) were included in thisstudy. There were three Yorkshire terriers, one German shepherd,one poodle, and eight mixed-breed dogs. Two dogs receivedsporadic oral hygiene at home, A professional scaling andpolishing had been performed on all dogs 6-months prior tosample collection. Antibiotics had been given to most ofthe dogsin the past for conditions other than periodontal disease. Noattempt was made to assess details of antibiotic history becauseowners were not able to verify names of antibiotics used, datesand routes of administration, duration of therapies, etc. However,dogs must not have received antibiotic therapy for at least 2-weeksbefore sample collection to be included in the study.

J,VET,DENT Vol. 23 No. 4 December 2006 219

Sample collection was performed under general anesthesia atthe right maxillary canine tooth (104) and the right maxillaryfourth premolar tooth (108) since both teeth had been excludedfrom prior periodontai probing, A sterile endodontic paper pointwas inserted into the depth of the gingival sulcus or periodontaipocket at buccal aspects of the teeth. The paper point wasremoved after a few seconds and placed into tubes containing atransport liquid media (thioglycollate broth)-' for growth ofaerobic and anaerobic bacteria. The samples were immediatelytransported to the reference laboratory and were vortexed to allow

Table 1Signalment of the 13 dogs enrolled in the study.

Variable

Sex

Age

Weight

Diet

Male

Female

< 5 years

5-10 years

> 10 years

<12kg

12+kg

Mixed

Dry

n

11

2

3

7

3

8

5

10

3

%

84.6

15.4

23.1

53.8

23.1

61.5

38.5

76.9

23.1

Table 2

Isolation of anaerobic bacteria.

Anaerobic bacteria

Peplostreptococcus + Porphyromonasgingivaiis

Bacteroides fragilisPrevotella Intermedia

Percent (%)

30.846.123.1100

Anaerobic bacteria

Peptostreptococcus +Porphyromonas gingivaiis

Prevotellaintermedia

Bacteroidesfragilis

the detachment of microbial cells. Two dilutions (Logio) weremade for all samples that were plated on Tryptic Soy Agar plateswitb 5 % sheep blood'' for aerobic bacteria and on Bnicella Agar^for anaerobic bacteria. The plates were incubated aerobically for24 to 48-hours at 37°C, and anaerobicalV for 48 to 72-hours at37°C.

The anaerobic flora was identified by growth on BnicellaAgaf, a medium containing Vit K and haemin. Gram's staining,Schaifer & Fulton's staining for spores, and API System 20A'were used as biochemical reference methods.

Aerobic bacteria were identified by their macroscopic {e.g..,morphology of colonies, presence of hemolysis) and microscopic{using Gram-staining) characteristics; moreover, biochemicaltests were performed using macro- or micrometbods*^. For theidentification oí Streptococcus strains, the presence of hemolysis(a partial or ß total) and the growth on Mitis SalivariusAgar^, amedium for tbe isolation and identification of the streptococci ofthe oral cavity, were evaluated. For identification oí Pasteurellamultocida, the lack of growth on Mac Conkey Aga)' wasevaluated.

Evaluation of microbial sensitivity/resistance to antibioticswas performed using the Kirby-Bauer reference method or theagar disk diffusion test. A bacterial suspension, performed insaline buffer (0.9 % NaCl), was delivered onto a Mueller-Hintonplate, and then the disks containing different antibiotic moleculeswere placed on the plate. After incubation at 37°C under aerobicor anaerobic atmosphere for 24 to 48-hours, the susceptibility ofeach microorganism was recorded to the following antibiotics:amikacin, amoxicillin + clavulanic acid, doxycycline,erythromycin, gentamycin, kanamycin, metronidazole (only foranaerobes), and sulfa-trimethoprim.^

ResultsResults of variables of signalment (sex, age, weight, and diet)

of the 13 dogs enrolled in the study are reported in Table 1. Themajority of dogs were male (84.6 %), 5 to 10-years of age (53.8%), < 12.0 kg (61.5 %), and eating a mixed (soft and dry) diet(76.9 %).

Of the anaerobic bacteria (Table 2), Bacteroides fi-agilis wasmost frequently isolated from subgingival samples, followed byPeptostreptococcus + Porphyromonas gingivaiis, and Prevotellaintermedia. Of the aerobic bacteria (Table 3), a-haemolyticStreptococcus was most frequently isolated, often associated withEscherichia coli or Pasteurella multocida.

Susceptibility of anaerobic and aerobic bacteria to variousantibiotics is shown in Tables 4-8. Resistance of isolated bacteriato tested antibiotics was generally high. Anaerobic bacteriaappeared to be susceptible to amoxicillin + clavulanic acid,doxycycline, and erythromycin, while aerobic bacteria appearedto be susceptible to amoxicillin + clavulanic acid, erythromycin,gentamycin, and sulfa-trimetboprim. Bacteroides fragilis wasresistant to all of the antibiotics tested.

DiscussionThe aim of the present investigation was to evaluate the

subgingival aerobic and anaerobic bacterial flora of 13 dogs with

220 J.VET.DENT Vol. 23 No, 4 December 2006

periodontal disease and the susceptibility of these bacteria toantibiotics currently approved in Italy for treatment of canineinfections. Except for the high prevalence of Bacteroidesß-agilis,the predominant subgingival flora obtained in this study confirmsresults reported in previous studies."•"•"'•'^•-"'-'- Of the anaerobicbacteria, Bacteroides fragilis was most frequently isolated,followed by Peptostreptococcus + Porphyromonas gingivalis andPrevotella intermedia. The reason for the unusually highprevalence oí Bacteroides fi-agilis is not clear. Differing resultsbetween isolation studies may be due to differences in studymethodology, including sample population utilized and isolationtechniques applied. Of the aerobic bacteria, a-haemolyticStreptococcus was most frequently isolated, often associated withEscherichia coli or Pasteurella nndtocida.

The fast growth rate, high concentration of cells, geneticprocesses of mutation and selection, and ability to exchange genesaccount for the extraordinary adaptation and evolution ofbacteria.'" For these reasons bacterial resistance to antibiotics maytake place very rapidly in evolutionary time. Risk factorsresponsible for the emergence and spread of resistant bacteriainclude: (1) antibiotic use; (2) reservoirs for resistance; (3)medical advances; and (4) societal changes.""' Antibiotics makeconditions favorable for overgrowth of some bacteria, includingthose that possess mechanisms of drug resistance. If a resistantorganism is present, antibiotics will create 'selective pressure'favoring the growth ofthat organism. A number of studies havedemonstrated conclusively that the development of bacterialresistance to antibiotics is correlated with the level of antibioticuse.'"^*' Antibiotic resistance of nosocomial pathogens in hospitals,nursing homes, day-care centers, and animal facilities is increasedby the transfer of individuals already colonized by resistantorganisms from one location to another. Progress in the treatmentof many diseases has led to an increased life span of humans andanimals. Consequently, with advanced age, chronic disease orimmunosuppression, individuals can be more susceptible tobacterial infections, resulting in greater use of antibiotics.Worldwide spread of bacterial resistance to antibiotics hasoccurred due to the increased mobility of today's society.-"-

Pet animal numbers have substantially increased in modemsociety, and attention is increasingly devoted to pet welfare.Antibiotics are frequently used in small animal practice, withheavy use of broad-spectrum agents such as amoxicillin +clavulanic acid, cephalosporins, and ñuoroquinoIones. Thepractice of antibiotic overuse and misuse in cats and dogs hascontributed to the development of Staphylococcus spp.,Escherichia coli and various other bacteria that are resistant toantibiotics."'"^^ The role of pets in the dissemination of bacterialresistance to antibiotics has been given relatively little attentionwhen compared with that of food animals, and a marked contrastis evident between the current policies on antibiotic usage incompanion and food animals. However, the possible transfer ofresistant bacteria from cats and dogs to humans has recently beenacknowledged as a potential threat to public health.""-̂ *

One of the biggest problems is inappropriate prescribing ofantibiotics. There are many reasons for this, including demandfrom patients/patient owners, time pressure on physicians/

veterinarians, and diagnostic uncertainty. Several recent studiesshowed that pediatricians prescribe antibiotics significantly moreoften, if they perceive parents expect them, and significantly lessoften, if they feel parents do not expect them."^** The best way tocombat this situation is to educate patients/patient owners anddoctors/veterinarians to decrease both demand and over-prescribing. Unfortunately, there is a tendency to use antibiotics aspart of the management of any animal with periodontal disease orother oral condition, although there is no apparent justification forthis practice. Similar to dogs in the present study, resistance ofplaque bacteria to antibiotics has clearly been demonstrated in

Table 3

isolation of aerobic bacteria.

Aerobic bacteria

a-hemolytic Sireptococcus + E. colia-hemolytic Streptococcus + P. fvultocidaa-hemoiytic Streptococcus + E. coli

+ P. muitocidaa-hemolytic Streptococcus + E. coli

+ S. intermediusa-hemolytic Streptococcus

S, intermedius + P. muitocida

Percent {%)

3838

8

8

8100

Aerobic bacteria

a-iiemolyticStreptococcusE. coii

a-hemolytic Streptococcus+ E. coli -h P. muttocida

a-fiemolytic Streptococcus+ E. cell + S. intermedius

a-hemolytic Streptccoccus+ S. intermedius+ P. multocida

a-hemolytic Streptococcus+ P. muitocida

Table 4

Antibiotic activity versus Prevotella intermedia.

Antibiotic

Amikacin

Amoxicillin-^CIavuianic acid

Doxycycline

Erythromycin

Gentamycin

Kanamycin

Metronidazole

Suifa-trimethoprim

Sensitivity (%)

-

66.7

33.3

66.7

-

-

-

-

Resistance (%)

100

33,3

66.7

33.3

100

100

100

100

J,VET,DENT, Vol. 23 No, 4 December 2006 221

Table 5Antibiotic activity versus Bacteroides fragilis.

Antibiotic

Amikacin

Amoxicillin+Clavulanic acid

Doxycycline

Erythromycin

Genlamycin

Kanamycin

Metronidazole

Sulfa-trimethoprim

Sensitivity (%)

-

-

-

-

-

-

-

-

Resistance (%)

100

100

100

100

100

100

100

100

Table 6Antibiofic activify versus Porphyromonas gingivalisPeptostreptococcus.

Antibiotic

Amikacin

Amoxicillin+Clavulanic acid

Doxycycline

Erythromycin

Gentamycin

Kanamycin

Metronidazole

Sulfa-trimethoprim

Sensitivity (%)

25

75

100

25

25

25

25

-

Resistance (%)

75

25

-

75

75

75

75

100

Table 7

Antibiotic activity versus a-haemolytic Streptococcus -f £coli.

Antibiotic

Amikacin

Amoxicillin+Clavulanic acid

Doxycycline

Erythrcmycin

Gentamycin

Kanamycin

Sulfa-trimethoprim

Sensitivity (%)

20

40

20

20

80

20

60

Resistance (%)

80

60

80

80

20

80

40

Table 8Antibiofic activity versus a-haemolyflc Streptococcus + P.multccida.

Antibiotic

Amikacin

Amoxicillin+Clavulanic acid

Doxycycline

Erythromycin

Gentamycin

Kanamycin

Sulfa-trimethoprim

Sensitivity (%)

-

-

-

40

-

-

Resistance (%}

100

100

100

60

100

100

100

humans.'"'''' It is therefore imperative to review periodontaltreatment strategies and determine whether systemic antibioticshave a role to play in the management of periodontal disease.

If accumulation of plaqne is prevented, periodontal diseasedoes not develop." Although this condition is caused by bacteria,antibiotic therapy is not considered the primary treatmentstrategy.'"^" Instead, treatment of periodontal disease should bedirected at mechanical removal or reduction of plaque andcalculus accumulation, suppression of the tissue-destructiveeffects of the inflainmatory response, surgical management ofperiodonfal pockets, extraction of more severely affected teeth,and thorough debridement of extraction sites.' A controlled-release local antibiotic delivery system, reachingperiodontopathogens deep within periodontal pockets, has beendescribed in dogs.^" Professional supra- and subgingival scaling,followed by daily tooth brushing, is the 'gold standard" forprevention of periodontal disease.' Home oral hygiene may beenhanced by offering products that support dietary abrasion orchemically suppress plaque and calculus accumulation.™

Bacteremia secondary to periodontal disease occui"s daily inpatients with periodontal disease, and it is normally rapidlycleared hy the reticulo-endothelial system in the healthy patient."'Therefore, for the great majority of otherwise healthy cats anddogs presenting with periodontal disease and other oralconditions, systemic antibiotics are not indicated.''" Bacteremiacan be prevented or reduced in severity by rinsing the oral cavity

Table 9

American Veterinary Dental College (AVDC) PositionStatement on fhe Use of Antibiotics in Veterinary Dentistry.

The AVDC endorses the use of systemic antibiotics inveterinary dentistry for treatment of some infectiousconditions of the orai cavity Alttiough cuiture andsusceptibility testing is rarely performed on individualpatients that have an infection extending from/to the oralcavity, ttie selection of an appropriate antibiotic should bebased on pubiisfied data regarding susceptibility testingof the spectra of known oral pathogens. Patients that arescheduled for an oral procedure may benefit from pre-treatment with an appropriate antibiotic to improve thehealth of infected oral tissues. Baoteremia is a recognizedseguela to dental scaling and other oral procedures.Healthy animais are able to overoome this bacteremiawithout the use of systemic antibiotics. However, use of asystemically administered antibiotic is recommended toreduce bacteremia for animals that are immunecompromised, have underlying systemic disease (suchas clinically-evident cardiac, hepatic, and renal diseases)and/or when severe oral infection is present. Antibioticsshould never be considered a monotherapy for treatmentof oral infections, and should not be used as preve •'••/emanagement of oral conditions. Adopted by the Bo.Directors. April 2005

222 J.VETDENT Vol. 23 No. 4 December 2006

with dilute chlorhexidine gluconate (0.12 %) prior tocommencing the oral procedure. Perioperative systemicantibiotics are indicated in: ( 1 ) debilitated andlnununocompromised patients; (2) patients suffering from organdisease, endocrine disorders, cardiovascular disease, and severelocal and/or systemic infections; and (3) patients havingpermanent implants and transplants. Unless there is a well-founded positive reason for their administration, systemicantibiotics should not be used.

Although there is a position statement on the use ofantibiotics in veterinary dentistry provided by the AmericanVeterinaiy Dental College (Table 9),"- compulsory guidelines forprudent prescription patterns and use of antibiotics in smallanimals with periodonta] disease or other oral conditions, whichdescribe the minimum requirements to be followed byveterinarians, are not available. Key elements of these guidelinesshould be the use of antibiotics on the basis of an exact(preferentially microbiological) diagnosis, choice of the mostsuitable antibiotic (antibacterial spectrum as narrow as possible,mai-gin of safety as high as possible, and good tissue penetrationif necessary), restricted use of antibiotics with last resortcharacter, and adherence to label instructions (no underdosing orprolongation of dosing interval, so-called "pulse dosing"). Anydeviation from the guideline recommendations must be justifiedand recorded."''̂

' ThioglycoUate Broth, Oxoid Ltd, Basingstoke, UK

'• Trypric Soy Agar plus 5 % Sheep Blood Plate, Oxoid Ltd, Basingstoke, UK

' Bruceila Agar, Oxoid Ltd, Basingstoke, UK

" Gas Pak System, Becton Dickmson, Franklin Lakes, USA

' Brucella Agar, Oxoid Ltd Basingstoke, UK

' API 20A System, BioMériéux, Lion, France

= API 20E and API 20NE Systems, BioMériéux, Lion, France

" Mitis Salivarius Agar, DIFCO, DID, Detroit, USA

' Mac Conkey Agar n°3, Oxoid Ltd, Basingstoke, UK

' Muelier-Hinton Agar, Oxoid Ltd, Basingstoke, UK

"̂ All disks used for antimicrobial sensitivity tests produced by Oxoid Ltd,

Basingstoke, UK

Author InformationFrom Via A. Volta 7 (Radice), 20030 Palazzolo M,se, Milano,Italy; the Department of Veterinary Pathology, Hygiene andPublic Health (Martino), Section of Microbiology andImmunology, Faculty of Veterinary Medicine - University ofMilan, Via Celoria, 10 - 20133 Milano, Italy; and the Matthew J.Ryan Veterinary Hospital of the University of Pennsylvania(Reiter), 3900 Delancey Street, Philadelphia, PA 19104Corresponding author Email: Reiter(gvet.upenn.edu

References1 Harvey CE. Management of periodontal disease: understanding ihe options Vet dm

North Am SmaliAnimPraot 2005; 35-819-83e.

2 Lindhe J Hamp S-E, et al. Plaque induced periodonlal disease in beagle dogs. A 4-yearclinical, roentgenographical and hislometrical study. JPer/odonfa/fles 1975,10.243-255.

3 Assi S. Indagine preiiminare sui batten aerobi ed anaerobi associati alie tasciie gengivaii

di cani con parodontopatie e ioro antibiotioo-sensibilità. Tesi di laurea, Reiatore Dott.ssaPA, Marlino, 2003 Facoitâ di Medicina Velennaria, Miiano

4, Courant PR, Saxe SR, Nasii L, Roddy S, Sulcuiar bacteria in the beagle dog,Periodontics 1968: 6: 250-252.

5. Harvey CE, Thornsberry C, et al. Subgingivai bacteria-comparison of culture results mdogs and cats with gingivitis. J Vet Dent 1995; 12:147-150.

6, Hennet PR, Harvey CE Aerobes in periodontal disease in the dog: a review. J Vel Dent1991; 8: 9-11,

7. Hennet PR, Harvey CE. Anaerobes in periodontai disease in the dog. A Review. J VetDenf 1991:8: 18-21.

8 Hennel PR, Harvey CE. Spirochetes m periodontal disease in the dog' a review J VetDenM991:8: 16-17.

9. isogai E, isogai H, etal, Orel flora of mongrei and beagie dogs with periodontai diseaseNippon JuigakuZasshi '^'äSQ.b^: 110-118,

10. Isogai H, Isogai E, ef al. Detection of serum antibodies of oral Porphyrornonas(Bacteroides) asaccharolyticus in dogs: relationship to periodontal disease. NipponJuigakuZasshn9e9: 5V. 1239-1241.

11. isogai HY, Kosako Y, et al. Ecology ol genus Porphyromonas in canine periodontaldisease. J Vet Med 81999, 46:467-473.

12. Leonhardt A, Bergiundh T, et al. Putative periodontal pathogens on titanium implants andteeth in experimental gingivitis and periodontitis in beagie dogs. Clin Orai impiants Res1992:3: 112-119.

13 Newman MG, Sandiei M, et ai. The effect ot dietary Gantrisin suppiernents on the floraof periodontal pockets in four beagie dogs. J Periodontai Res 1977: 12: 129-134

14. Nieves MA, Hartwig P, et al. Bacteriai isolates from plaque and Irom blood during andafter routine dental procedures m dogs Vet Surg 1997: 25: 26-32.

15 Sarkiaia EM, Asikainen SE. et ai. The efficacy ot tinidazoie in naturally occurringperiodontitis in dogs, bactenoiogical and ciinical results Vet Microbioi 1993; 36' 273-288,

16 Svanberg GK, Syed SA, et ai. Differences between gingivitis and periodontitisassociated microbiai fiora in the beagle dog. Relationship ot plaque parameters tohistoiogical parameters of periodontai disease J Periodontai Res 19B2: 17: 1-11.

17. Syed SA Characteristics of Bacteroides asaccharoiyticus trom dental piaques of beagledogs. J dm MicroPiot 1980, 11 • 522-526.

18. Syed SA, Svanberg M, et ai. rhe predominant cuitivable dentai plaque fiora ot beagiedogs with gingivitis. J Periodontai Res 1980. 15- 123-136.

19. Syed SA, Svanberg M, et ai rhe predominant cuitivabie dentai plaque flora of beagledogs wilh periodontitis J Clin Periodontoiim^; 8: 45-56.

20. Takada K, Hirasawa M Expression of trypsin-like activity by the generaCorynebacterium and Actinomyces in canine periodontitis. J Med Microbio! 2000;49: 621-625.

21. Wunder JA, Briner WW, ei al. Identifie al ion of Ihe cultivable bacferia in dental plaquefrom the beagle dog. JDenf Res 1976; 55: 1097-1102

22. Williams RC, Leone CW, et al Tetracycline treatment of periodontal disease in the beagiedog, il rhe cultivable periodontal pocket fiora J Feriodcntai Res 1981, 16:666-674.

23. Allaker RP, Rosayro R, et al. Prevalence of Porphyromonas and Prevotella species in thedental piaque of dogs. VetRec 1997, 140. 147-148

24 Saito A, Hosaka Y, et al. Responses of peri-implant tissues to undisturbed plaqueformation in dogs, clinical, radiographie, and microbioiogical findings. Buil Tokyo DentCoi/1997; 38.13-20.

25. Yamasaki T, Nagata A, et ai. Black-pigmented, asacctiarolytic Bacteroides speciesresembling Porphyromonas gingivaiis (Bacteroides gingivaUs) trom beagle dogs. OralMicrcbiol Immunoi 1990: 5:332-335

26 Fournier D, Mouton C, et al Porphyromonas guiae sp. nov, an anaerobic, gram-negative coccobacillus from the gingivai suicus of various animal hosts, tnt J Syst EvolMicrobio! 20O1 ; 51:1179-1189.

27. Allaker RP, Young KA, et al. Dental plaque flora of the dog with reference to fastidiousand anaercbic bacteria asscciated with bites J Vet Dent 1997: 14: 127-130.

28 Boyce EN, Ching RJ, et al Occurrence of gram-negative black-pigmented anaerobes insubgingivai plaque during the development of canine periodontai disease. Clin infectDis 1995: 20(Suppl 2) S317-319.

29 Coliins MD, Love DN, et al. Phylogenetic analysis of members of the genusPorphyromonas and description of Porphyromonas cangingivalis sp. nov, andPorphyromonas cansuici sp, ncv, int J Syst Bacterioi 1994: 44:674-679.

30, Hardham J, Dreier K, et al Pigmented-anaerobic bacteria associated with canineperiodontitis. Vet Microbioi 20Qb\ 106:119-128.

J.VET.DENT Vol,23No, 4 December 2006 223

31 Chung CP. Nisengard R, et al Bacterial antibody ttters in ligature-induced periodonliiis mbeagle dogs. J Periodonlol 1983: 54: 236-246

32. Mikx FH, Ngassapa DN, el al. Effecl of splint placemeni on blaok-pigmented Bacteroidesand spirochetes in the dental plaque of beagle dogs. J Dent Res 1984; 63: 1284-1288.

33 Mikx FH, Maltha JC, el ai. Spirochetes in early lesions of necrotizing uiceralive gingivitisexpenmentaily induced in beagles. Oral Microbiol Immunol 1990: 5: 86-89.

34. Riviere GB, Thompson AJ, ei al. Detection of pathcgen-related oral spiroohetes,Treponema denticoia. and Treponema socranskii in dental piaque from dogs. J Vel Dent1996: 13: 135-138.

35. Valdez M, Haines R, et al. isolation of orai spirochetes from dogs and cats and provisionaiidentification using polymerase chain reaciion (PCR) analysis specific for human plaqueTreponema spp. J Vet Dent 2000: 17: 23-26.

36. Harvey CE. Thcrnsberry C. el ai Antimicrobiai susceptibility of subgingiuai bacteriai florain dogs with gingivitis. J Wsf Denf 1995: 12: 151-155.

37. Harvey CE, Thornsberry C, et ai. Antimicrobial susceptibiiily of subgingivai baotenai florameats with gingivitis. J l̂ ei Denf 1995, 12- 157-160.

38 Preshaw PM Antibiotics m the treatment of periodontitis. Dent Update 2004, 31 • 448-456

39. Saikiaia E. Harvey CE. Systemic antimicrobials in the treatment of periodontitis in dogs.Sem Vet Med Surg 1993, 8: 197-203

40. Feres M, Haffajee AD, et al. Antibiotic resistance of subgingivai species during and afterantibiotic therapy. J Clin Penodonlol 2002: 29: 724-735.

41. Handai T, Caugant DA, e1 ai. Antibiotic resistance in bacteria isoiated Irom subgingivalplaque in a Norwegian popuiation with refractory marginai periodontitis. Antimict AgentsChemother 2003. 47: 1443-1446.

42 Ready D, Lancaster H, et al. Effecl of amoxiciilin use on orai miorobiota in young childrenAntimicr Agents C/iemoifter 2004, 48: 2883-2887

43. Winkeihoff AJ. Herrera D, et al Antimicrobial profiles of periodontal pathogens isolatedfrom periodontitis patients in the Netheriands and Spain. J Clin Periodontol 2005: 32: 893-

59. Hayashi K, Takada K, et al. Clinical and microbiologrcai effects ot controlied-reiease localdeiivery of minocycline on periodontitis in dogs. Am J Vel Res 1998: 59: 464-467

60. Roudebush P, Logan E, et al. Evidence-based veterinary dentistry: a systematic reviewol homecare for prevention of periodontal disease in dogs and cats. J Vet Dent 2005:22:6-15

61. Sliver JG, fviartin L, fvicBride BC Recovery and clearance ol oral microorganismsfollowing experimental bacleremias in dogs Arch Oral Bio! 1975: 20' 675-679

62. Website of the American Veterinary Dental Coliege (AVDC): hltp://avdc org/position-statements.html#AB.

63. Ungemach FR, Wuller-Bahrdt D, et al. Guidelines for prudent use of antimicrobials and¡heir implications on antibiotic usage in veterinaiy medicine Int J Med Microbiol 2006,httpi/wwwncbl.nlm.nih.gov/entiez/query.tcgi?cmd-Retneve&db=pubmed&dopt=Abstractâlist_uids=16520092Squery_hl=1Silool=pubmed_docsum.

64. Weese JS. Investigation of antimicrobial use and the impact of antimicrobial useguideiines in a smali animal veterinary teaching hospital: 1995-2004. J Am Vet MedASSOC 2006: 228: 553-558.

44 Guardabassi L, Schwarz S, et al Pet animais as reservoirs of antimicrobiai-resistantbacteria. J Antimicrob Chemother 200A: 54' 321-332.

45. Website of the Department of Health and Human Seivioes, Centers tor Disease Controland Prevention (CDC¡. http://www.cdc.gov/drugresistance/community/

46. Cohen FL. Tartasky D. Microbial resistance todiug therapy, a review. Am J Infect Control1997: 25: 51-64

47. Hanberger H. Hoffmann M, et al. High incidence of antibiotic resistance among bacteriain lour intensive care units at a university hospital in Sweden Scand J Infect Dis 1997:29:607-614.

48 Muder RR, Brennen C, et al. Multiply antibiotic-resistant gram-negative bacilli in a long-term-care faciiity: a case control study of patient tisk factors and prior antibiotic use.Infect ConliOl Hosp Epidemiol 1997, 18 809-813.

49. Cohn LA, Gary AT, et ai. Trends in fluoroquinoione resistance of bacteria isoiated fromcanine urinary tracts. J Vet Diagn Invest 2003; 15: 338-343.

50. Gortel K, CamplDell KL, et al. Methioillin resistance among staphylococoi isolated fromdogs. Am J Vet Res 1999: 60' 1526-1530.

51. Lanz R, Kuhnert P, et al. Antimiorobial resistance and resistance gene determinants inclinical Escherichia co//from different animal species in Switzerland. Vet Microbio!2003:91:73-84.

52. Rantala M. Lahti E, et ai.. Antimicrobiai resistance in Staphylocooous spp , EscheriohiacoH ar\ö Enterococcus spp. in dogs given antibiotics for chronic dermatoiogicaldisorders, compared with non-treated control dogs. Acta Vet Scand 2004, 45: 37-45.

53. Sanchez S, McCrackin Stevenson MA, et ai. Characterization of m ulti dru g-resistantEsoherichia coti isoiates associated with nosocomiai infections in dogs J Clin Microbiol2002: 40: 3586-3595

54. Maiik S, Peng H. et ai. Antibiotic resistance in staphyiocccci associated with cats anddogs JAppi Microbio! 2005. 93: 1283-1293.

55. Christakis DA, Wright JA, et al. Association between parental satisfaction and antibioticprescription for children with cough and coid symptoms. Pediatr Infect Dis J 2005:24: 774-777.

56. Mangione-Smith R, MoGiynn EA, et al. Parent expectations for antibiotics, physician-parent communication, and satisfaction Arch Pediatr Adolesc Med 2001: 155' 800-806.

57. Mangione-Smith R, Stivers T, et al. Online commentary during the physical examinationa communication tool lor avoiding inappropriate antibiotic prescribing? Soc Sei Med2003:56:313-320.

58 Watson RL. Doweli SF. et ai Antimicrobiai use for pediatnc upper respiratory infections:reported practice, actuai practice, and parent beiiefs Pediatrics 1999: 104. 1251-1257.

224 J.VETDENT Vol. 23 No. 4 December 2006