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Relationship of biocide use to antibiotic resistance Stuart B. Levy, M.D. Tufts University School of Medicine Alliance for the Prudent Use of Antibiotics.

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Presentation on theme: "Relationship of biocide use to antibiotic resistance Stuart B. Levy, M.D. Tufts University School of Medicine Alliance for the Prudent Use of Antibiotics."— Presentation transcript:

1 Relationship of biocide use to antibiotic resistance Stuart B. Levy, M.D. Tufts University School of Medicine Alliance for the Prudent Use of Antibiotics

2 It’s A Question of Residues Non-residues ? Triclosan QACs Triclocarban Bleach Peroxides Alcohols Residues

3 Cross- and Co- Resistance (Biocides and antibiotics) Target mutations Multidrug efflux systems Plasmids & transposons

4 O Cl Cl HO Cl Triclosan

5 Triclosan Resistance AG100 AG100 (low) AG100 (medium) AG100 (high) MIC (µg/ml) Fold Change Mutated Gene --- fabI (F203L) fabI (M159T) fabI (G93V)

6 Inhibitors of Enoyl reductase (fabI, inhA) TriclosanDiazaborine Isoniazid

7 Mutations in InhA confer triclosan resistance in Mycobacterium smegmatis Strain Selected InhA Relative MIC on* mutation (in 7H9 medium) Triclosan Isoniazid mc (wt) -- none MT 1 TRC M161V MT 9 TRC M103T MT 17 TRC A124V mc INH S94A mc none 6.3 >64 (p::inhA) *TRC = triclosan, INH = isoniazid McMurry et al, AAC 43:711, 1999.

8 Efflux as a Common Mechanism of Biocide and Antibiotic Resistance

9 mar acrAB antibiotics organic solvents pine oils bile salts triclosan chloroxylenol quaternary amines chlorhexidine

10 Biocide resistance and antibiotic resistance: Regulators and efflux pumps Biocide Inducer/SubstrateAffected proteinsDrugs QACs, chlorhexidine, triclosan Morita et al JAC: 51:991 (2003) NfxB MexCD-OprJ (P. aeruginosa) Multiple antibiotics Triclosan Schweizer et al AAC 42:394 (1998) Schweizer FEMS Microb Lett 202:1 (2001) MexAB-OprM MexJK (P. aeruginosa) Multiple antibiotics

11 Genetic linkage of resistance to QACs and to ß-lactam antibiotics in staphylococci Sidhu et al MDR 7:363 (2001) Sidhu et al AAC 46:2797 (2002)

12 DECREASED DRUG SUSCEPTIBILITY DRUG RESISTANCE Penicillin resistant S. pneumoniae Fluoroquinolone resistant E.coli Vancomycin resistant S. aureus

13 Triclosan MIC (ug/ml) % of total isolates S. aureus N=43 S. capitis N=42 S. epidermidis N=73 S. warneri N=155 Triclosan Susceptibility (Staphylococcus) A. Aiello et al. Antimicrob. Agnts. Chemother. 48: , Household hand isolates

14 Triclosan Susceptibility Klebsiella pneumoniae (N = 69) Triclosan MIC (ug/ml) % of total isolates Household hand isolates A. Aiello et al. Antimicrob. Agnts. Chemother. 48: , 2004.

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16 Antibiotic susceptibility of MRSA and benzalkonium chloride resistant derivatives MIC (  g/ml) Antibiotic MRSA ParentBZ-R-1 BZ-R-2 Oxacillin Cloxacillin Moxalactam Flomoxef Cefmetazole Cephalothin Ampicillin Chloramphenicol Ofloxacin Tetracycline Benzalkonium chloride Akimitsu et al, AAC 43:3042, 1999.

17 S. Langsrud et al. Appl. Microb. 140:321 (2003) Antibiotic Susceptibility of Benzalkonium Chloride selected mutants

18 Figure 2. Proportion of study participants with >1 bacterial species resistant to an antimicrobial agent on their hands. In the group that used antibacterial products, 82 and 105 hand samples were available at baseline and at year-end, respectively. In the group that used nonantibacterial products (i.e., plain soap), 82 and 96 hand samples were available at baseline and at year-end, respectively. Aiello, et al. Emerg Inf Dis 11:1565, Antibiotic Resistance and Hand Soaps

19 Resistance evolves in time and volume of drug

20 VISA VRSA MRSAPen R SA Evolution of MDR in S. aureus Penicillin Methacillin Vancomycin

21 Contributors to Drug Resistance TODAY ANTIBIOTICS (people, animals, agriculture) DRUG RESISTANT MICROBES BIOCIDES

22 Contributors to Drug Resistance ANTIBIOTICS (people, animals, agriculture) DRUG RESISTANT MICROBES BIOCIDES TOMORROW?


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