Dr.T.V.Rao MD

MULTI DRUG RESISTANT BACTERIA

Dr.T.V.Rao MD 1

A Tribute to - Fleming and Penicillin

Dr.T.V.Rao MD 2

Brief History of Antibiotics• 1928- Penicillin discovered by Fleming

• • 1932- Sulfonamide antimicrobial activity discovered ( Erlich)

• • 1935- First unsuccessful attempt to use Sulfonamide to treat

• • a case of meningitis

• • 1943- Drug companies begin mass production of penicillin

• • 1948- Cephalosporins precursor sent to Oxford for synthesis

• • 1952- Erythromycin derived from Streptomyces erythreus

• • 1956- Vancomycin introduced for penicillin resistant staphylococcus

Dr.T.V.Rao MD 3

Recent Antibiotics in Use• • 1962- Quinolone antibiotics

first discovered

•• 1970s- Linezolid discovered but not pursued

•• 1980s- Fluorinated Quinolones introduced, making then clinically useful

•• 2000- Linezolid introduced into clinical practice

Dr.T.V.Rao MD 4

The Magic Bullets• Antibiotics revolutionised medicine

• The first antibiotic, penicillin, was discovered by Alexander Fleming in 1929

• It was later isolated by Florey and Chain

• It was not extensively used until the 2nd World War when it was used to treat war wounds

• After 2nd World War many more antibiotics were developed

• Today about 150 types are used

•Most are inhibitors of the protein synthesis, blocking the 70S ribosome, which is characteristic of prokaryotes

© 2008 Paul Billiet ODWS Dr.T.V.Rao MD 5

Survival of the Fittest.Darwin’s theory rules the Microbes

•Various microorganisms have survived for thousands of years by their being able to adapt to antimicrobial agents. They do so via spontaneous mutation or by DNA transfer. These microorganisms employ several mechanisms in attaining multidrug resistance

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Resistance• It took less than 20 years for,

bacteria to show signs of resistance

• Staphylococcus aureus, which causes blood poisoning and pneumonia, started to show resistance in the 1950s

• Today there are different strains of S. aureus resistant to every form of antibiotic in use

S Dr.T.V.Rao MD 7

Multiple drug resistance•Multiple drug resistance or

Multidrug resistance is a condition enabling a disease-causing organism to resist distinct drugs or chemicals of a wide variety[1] of structure and function targeted at eradicating the organism. Organisms that display multidrug resistance can be pathologic cells, including bacterial .

Dr.T.V.Rao MD 8

MDRO: Definition

•Multidrug-Resistant Organisms (MDROs) are defined as microorganisms that are resistant to one or more classes of antimicrobial agents.

•Three most common MDROs are:

1. Methicillin-Resistant Staph aureus (MRSA)

2. Vancomycin Resistant Enterococci: (VRE)

3. Extended Spectrum Beta-Lactamase producing Enterobacteriaceae. (ESBLs)

CDC: Management of Multidrug-Resistant Organisms in Healthcare Settings, Healthcare Infection Control Advisory Committee, Jane D. Siegel et. al. pg 7-12

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Antibiotic Pressure and Resistance in Bacteria

What is it ?•”Selection pressure of antibiotics has led to the emergence of antibiotic-resistant bacteria.”

•Antibiotics can effect bacteria unrelated to the targeted infectious agent; these may be “normal” flora, leading to the emergence of resistant mutants inhabiting the same environment.

Baquero et al., International Report 1996;23:819Dr.T.V.Rao MD 10

Settings that Promote Drug Resistance

� Day-care centers

� Long term care

facilities

� Homeless

shelters

� Jails

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� Intensive care

units

� Oncology units

� Dialysis units

� Rehab units

� Transplant units

� Burn units

Location contributing to Drug

Resistance

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Transposons & Integrons

•Resistance genes are often associated with transposons, genes that easily move from one bacterium to another

•Many bacteria also possess integrons, pieces of DNA that accumulate new genes

•Gradually a strain of a bacterium can build up a whole range of resistance genes

•This is multiple resistance

•These may then be passed on in a group to other strains or other species

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Antibiotics promote resistance

• If a patient taking a course of antibiotic treatment does not complete it

• Or forgets to take the doses regularly,

• Then resistant strains get a chance to build up

• The antibiotics also kill innocent bystanders bacteria which are non-pathogens

• This reduces the competition for the resistant pathogens

• The use of antibiotics also promotes antibiotic resistance in non-pathogens too

• These non-pathogens may later pass their resistance genes on to pathogens

ODWS

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Multi-resistance

• Multi-resistance

• Multi-resistance to different antibiotics generally results from a combination of different independent mechanisms of resistance. -P aeruginosa is a type of multi-resistant bacteria. It is resistant to β-lactams,

• including third-generation cephalosporins, quinolones, chloramphenicol, and Tetracycline's. (natural resistance)

• -Methicillin-resistant strains have become resistant to most antibiotics and with a high frequency of high resistance. (acquired)

• Cross-resistance

• Cross-resistance Occurs generally in antibiotics of the same family.

• -Cross-resistance between penicillin's, more widely between all the β-lactams

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Consequences of Antimicrobial Resistance• Compromised therapy of

human infections

• • Serious complications for elderly and children

• • Increased length of therapy and more doctor visits

• • Prolonged hospital stay and significant increase of treatment cost

• “Bacterial resistance is a major threat to public health”

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Folic acid synthesis

ß-lactams & Glycopeptides (Vancomycin)

50 50 50

30 30 30

DNA

mRNA

Ribosomes

PABA

DHFA

THFA

Cell wall synthesis

DNA gyrase

Quinolones

Protein synthesis inhibition

Protein synthesis inhibitionTetracyclines

Protein synthesis mistranslation

Macrolides &

Lincomycins

Cohen. Science 1992; 257:1064

DNA-directed RNA polymerase

Rifampin

Aminoglycosides

Sulfonamides

Trimethoprim

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Causes of Resistance in MDROs•Enzymatic degradation

•Mutation at binding site

•Down regulation of outer membrane proteins

•Efflux pumps

•Transduction of genes

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Mechanisms of Resistance: Efflux

• Active, energy dependent pumps cause efflux of drugs

Bacterial Cytosol

PG layer

Outer membrane

drug

Efflux pump

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Antibiotic Pressure and Resistance in BacteriaWhy is it important?

•Antibiotic resistance has developed in almost all classes of bacteria of pathogenic potential.

•Resistance in organisms of low virulence can emerge as important pathogens.

•The development of resistant bacteria has driven pharmaceutical research to develop more potent, broad-spectrum antibiotics.

•Use of these in turn, has fueled the appearance of bacteria with newer modes of resistance.

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INCREASING PREVALENCE OF ANTIMICROBIAL RESISTANT MICROBES

•Hospital-acquired infections

• Methicillin-resistant staphylococci

• Vancomycin-resistant staphylococci

• Vancomycin-resistant enterococci

• ESC-resistant Gram-negative bacteria

• Azole-resistant CandidaDr.T.V.Rao MD 22

1.Methicillin-Resistant Staph aureus(MRSA)

• These are organisms that are not sensitive to common penicillin based drugs such asmethicillin, amoxicillin, penicillin, oxacillin1

• Normal flora- lives on human skin, noses, vaginal tract

•May cause infections if enters the body

• Contagious- through person to person contact

• Treatment - Vancomycin

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Vancomycin Resistant Enterococci (VRE)• Enterococci resistant to

Vancomycin

• Present in human body such as urinary tract and GI tract.

• Contagious

• Hospital patients can get it from contact via health care providers.

• Normal flora that may cause disease especially in vulnerable populations:• Eg elderly, children and

immunocompromised patients.

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Vancomycin Resistant Enterococci (VRE)• VRE include:

• Enterococcus faecalis

• Enterococcus faecium

• Treated with Synercid (quinupristin and dalfopristin)

• VRE can live on surfaces for up to 7 days!!!

• Haemophilus influenzae

lives about 2 days

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VRE prevention• Standard precautions

• Hand hygiene

•Personal Protective Equipment (PPE)

•Needle stick and sharps injury prevention.

•Cleaning & disinfection

•Respiratory hygiene (Cough Etiquette)

•Waste disposal

• Safe injection practices

Center for Disease Control and Prevention: http://www.cdc.gov/ncidod/dhqp/pdf/ar/mdroGuideline2006.pdf Accessed June 17th 2009Dr.T.V.Rao MD 26

Extended Spectrum Beta-Lactamase producing Enterobacteriaceae. (ESBL)

• ESBLs are plasmid-mediated beta lactamases described in gram negative bacilli2

• Eg. Klebsiella, Acinetobacter

•MOA – hydrolysis of beta- lactam ring in

• Penicillin's

• Narrow spectrum cephalosporins

• Beta-lactamase inhibitors inhibit ESBL producing strains

• Clavulanic acid

• Sulbactam

• Tazobactam.

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Enzymatic degradation of ESBLs:Mechanisms of ββββ-lactamase

N

O

N

O

OH

S CH3

CH3O

RH

β-lactamase

CH2

OHβ-lactamase

CH2

OH

N

O

N

O

OH

S CH3

CH3O

RH

β-lactamase

CH2

O

H H2O

N

O

N

O

OH

S CH3

CH3O

RH

H

OHβ-lactamase

CH2

OH

+

Hydrolysis of Oxyimino group

Penicillin drug

Inactivated drugDr.T.V.Rao MD 28

Other Drug Resistant Diseases

•Extensively-Drug Resistant Tuberculosis (XDR-TB)• This is a TB causing organism that is resistant to almost all

drugs that are used to treat TB.• Isoniazid

• Rifampin

• Fluoroquinolones

• At least one of: Amikacin, kanamycin, capreomycin

• The main cuasitive organism is Mycobacterium tuberculosis3

• Contagious through droplets but slower than viral infection such as flu

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CDC ReportsThree Enterobacteriaceae isolates

carrying a newly described resistance mechanism, the New Delhi metallo-beta-lactamase (NDM-1) , were identified from

three U.S. states at the CDCantimicrobial susceptibility laboratory. This is the first report of NDM-1 in the United States, and the first report of metallo-beta-lactamase carriage among Enterobacteriaceae in the

United States

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CDC reports the new genetic mechanisms• The isolate, Klebseilla pneumoniae 05-

506, was shown to possess a metallo-beta-lactamase (MBL) but was negative for previously known MBL genes. Gene libraries and amplification of class 1 integrons revealed three resistance-conferring

regions; the first contained bla(CMY-4) flanked by ISEcP1 and blc. The second region of 4.8 kb

contained a complex class 1 integron with the gene cassettes arr-2, a new erythromycin esterase gene; ereC; aadA1; and cmlA7

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Genetic origin of the NDM-1

• An intact ISCR1 element was shown to be downstream from the qac/sul genes. The third region consisted of a new MBL gene, designated bla(NDM-1), flanked on one side by K. pneumoniae DNA and a truncated IS26 element on its other side. The last two regions lie adjacent to one another, and all three regions are found on a 180-kb region that is easily transferable to recipient strains and that confers resistance to all antibiotics except fluoroquinolones and colistin. NDM-1 shares very little identity with other MBLs, with the most similar MBLs being VIM-1/VIM-2, with which it has only 32.4% identity.

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Molecular configuration of NDM-1•NDM-1 also has an

additional insert between positions 162 and 166 not present in other MBLs. NDM-1 has a molecular mass of 28 kDa, is monomeric, and can hydrolyze all beta-lactams except aztreonam. Compared to VIM-2, NDM-1 displays tighter binding to most Cephalosporins.

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NDM genetic coding differs from other recent isolates

•Compared to VIM-2, NDM-1 displays tighter binding to most cephalosporins, in particular, cefuroxime, cefotaxime, and cephalothin (cefalotin), and also to the penicillins. NDM-1 does not bind to the carbapenems as tightly as IMP-1 or VIM-2 and turns over the carbapenems at a rate similar to that of VIM-2. In addition to K. pneumoniae 05-506, bla(NDM-1) was found on a 140-kb plasmid in an Escherichia coli strain isolated from the patient's feces, inferring the possibility of in vivo conjugation

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Antibiotic use and Major abuse•Viral infections are not stopped by antibiotics

•Yet doctors still prescribe (or are coerced into prescribing) antibiotics to treat them

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INCREASING PREVALENCE OF ANTIMICROBIAL RESISTANT MICROBES

• Community-acquired infections• Multidrug resistant pneumococci

• Drug-resistant H. influenzae

• FQ- and ESC-resistant Salmonella

• Multidrug resistant Shigella

• FQ-resistant gonococci

• Multidrug-resistant M. tuberculosis

• Drug-resistant malaria

• Drug-resistant HIV

Dr.T.V.Rao MD 36

Nosocomial infections – Attains Higher Resistance.

•Major nosocomial pathogens increasingly resistant to antimicrobial drugs include Escherichia coli, Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus species, and Pseudomonas aeruginosa . Infections from methicillin- resistant staphylococci, vancomycin-resistant enterococci (VRE), and aminoglycoside-resistant Pseudomonas spp. are becoming common.

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Antibiotic Misuse – Consequences.•Large amounts of antibiotics used for human therapy, as

well as for farm animals and even for fish in aquaculture, resulted in the selection of pathogenic bacteria resistant to multiple drugs. Multidrug resistance in bacteria may be generated by one of two mechanisms. First, these bacteria may accumulate multiple genes, each coding for resistance to a single drug, within a single cell. This accumulation occurs typically on resistance (R) plasmids. Second, multidrug resistance may also occur by the increased expression of genes that code for multidrug efflux pumps, extruding a wide range of drugs.

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Bacteria attains Resistance by Complex Mechanisms

• # No longer relying on a glycoprotein cell wall

• # Enzymatic deactivation of antibiotics

• # Decreased cell wall permeability to antibiotics

• # Altered target sites of antibiotic

• # Efflux mechanisms to remove antibiotics[3]

• # Increased mutation rate as a stress response[4

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Gene Transfers play a Major rule in Antibiotic Resistance

• Many different bacteria now exhibit multidrug resistance, including staphylococci, enterococci, gonococci, streptococci, salmonella, Mycobacterium tuberculosis and others. In addition, some resistant bacteria are able to transfer copies of DNA that codes for a mechanism of resistance to other bacteria, thereby conferring resistance to their neighbors, which then are also able to pass on the resistant gene. This process is called horizontal gene transfer.

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Role of clinical Microbiology Laboratories

•The clinical laboratory has several critical roles in controlling hospital-acquired infections: accurately identifying nosocomial pathogens, detecting unexpected antimicrobial-drug resistance, and epidemiologic typing

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Antibiotic Pressure and Resistance in BacteriaWhat factors promote their development and spread ?

� Alteration of normal flora

� Practices contributing to misuse

of antibiotics

� Settings that foster drug

resistance

� Failure to follow infection control

principles

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� Inappropriate specimen

selection and collection

� Inappropriate clinical tests

� Failure to use

stains/smears

� Failure to use cultures and

susceptibility tests

Practices Contributing to

Misuse of Antibiotics

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Use of antibiotics with no clinical indication (eg, for viral infections)

Use of broad spectrum antibiotics when not indicated

Inappropriate choice of empiric antibiotics

•Lack of quality control in manufacture or outdated antimicrobial

• Inadequate surveillance or defective susceptibility assays

•Poverty or war

•Use of antibiotics in foods

Inappropriate Antibiotic Use

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� Inappropriate dose - ineffective concentration of antibiotics at site of infection

� Inappropriate route - ineffective concentration of antibiotics at site of infection

� Inappropriate duration

Inappropriate Drug Regimen

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Newer methods too have limitations•Most new rapid tests are

not yet helpful for infection control purposes, and automated systems for bacterial identification and susceptibility testing are not as reliable as desired for detecting organisms with emerging drug resistance

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Microbiology Laboratories to Play Greater Role

•A microbiology laboratory fully equipped to cooperate in the management of nosocomial infections will also have the necessary infrastructure to act as a sentinel to detect new antimicrobial agent resistance

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Implication of MDROs•Increase hospital stay

•Average 3-5 additional days

•Increase hospital costs

•Increase morbidity and mortality

CDC: Management of Multidrug-Resistant Organisms in Healthcare Settings, Healthcare Infection Control Advisory Committee, Jane D. Siegel et. al. pg 7-12Dr.T.V.Rao MD 48

MDROs prevention•Observe the universal standard precautions

•Practice 200% percent safety rule

•Good hygiene practice

•Frequent hand wash

•Cover cuts and scrapes

•Do not share personal items eg razors

•Do not pressure doctors for antibiotics

•Finish all antibiotic medications

•Health care providers to wash hands before touching patients

•Isolation for serious cases

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Proposals to Combat Antimicrobial Resistance

•Speed development of new antibiotics

•Track resistance data nationwide

•Restrict antimicrobial use

•Direct observed dosing (TB)

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Proposals to Combat Antimicrobial Resistance

•Use more narrow spectrum antibiotics•Use antimicrobial cocktails

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Limiting Antibiotic Resistance• Use antibiotics only for

bacterial infections

• Identify the causative organism if possible

• Use the right antibiotic; do not rely on broad-range antibiotics

• Not stop antibiotics as soon as symptoms improve; finish the full course

• Not use antibiotics for most colds, coughs, bronchitis, sinus infections, and eye infections, which are caused by viruses.

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Physicians Can Impact

Other clinicians

Patients

Optimize patient evaluation Adopt judicious antibioticprescribing practicesImmunize patients

Optimize consultations with other cliniciansUse infection control measuresEducate others about judicious use of antibiotics

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Future – Developing New Antibiotics•Antimicrobial peptides

•Broad spectrum antibiotics from plants and animals•Squalamine (sharks)

•Protegrin (pigs)

•Magainin (frogs)

•Antisense agents

•Complementary DNA or peptide nucleic acids that binds to a pathogen's virulence gene(s) and prevents transcription

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World Health Day 2011• For World Health Day 2011, WHO

will launch a worldwide campaign to safeguard these medicines for future generations.

Antimicrobial resistance - the theme of World Health Day 2011- and its global spread, threatens the continued effectiveness of many medicines used today to treat the sick, while at the same time it risks jeopardizing important advances being made against major infectious killers.

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Hand Washing is A Great Investment in Controlling Multi Drug Resistant Strains

The Programme is dedicated to Ignaz PH Semmelweis

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• The Programme is created by Dr.T.V.Rao MD for ‘ e ‘ learning resources on Awareness on

Implications of Antibiotic Misuse and

Consequces.

•Email

•doctortvrao@gmail.com

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