Antibiotic

1
Antibiotic Antibacterial Resistance of Skin
Bacteria from Users Non-Users of Antibacterial
Wash Products

• Eugene C. Cole, DrPH
• Brigham Young University
• Provo, Utah

2
Organization

• Study conducted through cooperative efforts of
  two applied research organizations
• Applied Environmental, Inc., Cary, NC
• Restoration Sciences, LLC, Cary, NC
• Study sponsored by
• The Soap and Detergent Association, Washington,
  DC

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Objective

• Investigate relationship between antibiotic and
  antibacterial resistance in human skin bacteria
• Staphylococcus aureus
• Coagulase-negative Staphylococcus sp.
• Isolated from forearm skin of persons routinely
  using or not using body washes and bath soaps
  containing, exclusively, either triclosan or
  triclocarban.

4
Summary

• These study results discount the speculative
  claim that the use of antibacterial wash products
  contribute to the selection and propagation of
  drug-resistant bacteria on human skin.

5
Approach

• Randomized study with 210 qualified male and
  female participants gt18 years
• 70 that frequently use body wash products
  containing only Triclosan (TCS)
• 70 that frequently use body wash products
  containing only Triclocarban (TCC)
• 70 that frequently wash, but do not use any
  antibacterial body wash products (Controls)

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Approach

• Users were defined as those using TCC or TCS wash
  products on a regular basis during the last 30
  days for body washing.
• Exclusion criteria disqualified persons from
  participating
• Antibiotic therapy within last 90 days
• Use of topical skin medications, medicated
  shampoos, anti-acne products
• Employment in health care, day-care, or animal
  care
• Frequent swimmer or hot tub user
• Routine exposure to solvents

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Approach

• Home visits confirmed qualification
• Forearm skin samples were collected
• Composite swab sample of both forearms,
  using a 4 x 16 cm (64 cm2 template)
• Lab processing by elution, plating on SBA and
  incubation for 18-24 hours at 37º C
• Colonies selected by criteria morphology,
  pigmentation, texture, hemolysis, etc
• Presumptive ID by gram stain, catalase, coagulase
• Confirmation by reference laboratory

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Approach

• Antibiotic susceptibility performed by
• Standard MIC testing using MicroScan method
• Testing conducted by LabCorp, NC
• Antibacterial susceptibility performed by
• Standard broth micro-dilution method (Barry et
  al, 1999), adapted from NCCLS method M7-A4
  (NCCLS, 1997)
• All isolates tested against TCC and TCS
• All results verified through appropriate QA
  procedures and microorganism control strains

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Approach

• Standard Antibiotic Susceptibility Panel
• Ampicillin
• Ciprofloxacin
• Clindamycin
• Erythromycin
• Nitrofurantoin

• Oxacillin
• Penicillin
• Tetracycline
• TMP/SMX
• Vancomycin

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Results

• 317 Staphylococcus isolates
• 301 CNS isolates
• Non-users (n 106)
• TCC users (n 102
• TCS users (n 93)
• 16 SA isolates
• Non-users (n 4)
• TCC users (n 7)
• TCS users (n 5)

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Results

• No isolates showed full or intermediate
  resistance to vancomycin
• S. aureus - MRSA
• Rates of resistance to oxacillin was less than
  reported rates for hospital-acquired and
  community-acquired MRSA
• 12.5
• 20.2 (Fridkin et al, 2002)
• 50.0 (Tiemersma et al, 2004)

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Results

• CNS - MR
• Rates of resistance to oxacillin was less than
  reported rates for hospital-acquired and
  community-acquired MR-CNS
• 20.6
• 43.6 (Fridkin et al, 2002)
• 73.3 (DUMC, 2005)

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Results

• MRSA
• NU 25.0 (1/4)
• TCC 0.0 (0/7)
• TCS 20.0 (1/5)
• MR-CNS
• NU 17.9 (19/106)
• TCC 23.5 (24/102)
• TCS 20.4 (19/93)

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Results

• Antibiotic Resistance - SA
• Distribution across all 10 drugs showed no
  significant differences among groups, even when
  TCC and TCS data were pooled and compared with NU
  results.
• Distribution across the 6 preferred drugs showed
  no significant differences among groups, even
  when TCC and TCS data were pooled and compared
  with NU results.

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Results

• Antibiotic Resistance - CNS
• Distribution across all 10 drugs showed no
  significant differences among groups, even when
  TCC and TCS data were pooled and compared with NU
  results.
• Greater tetracycline resistance in NU group
  isolates.

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Results

• Antibiotic Resistance to more than 1 preferred
  drug
• CNS - for 69 isolates, rates of resistance for
  each of the 3 groups were comparable
• NU 25.5 (27/106)
• TCC 24.5 (25/102)
• TCS 18.3 (17/93)

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Results

• Antibiotic Resistance to more than 1 preferred
  drug
• SA - for 2 isolates, rates of resistance for each
  of the 3 groups were comparable
• NU 25.0 (1/4)
• TCC 00.0 (0/7)
• TCS 20.0 (1/5)

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Results

• Antibacterial (TCC/TCS) Resistance
• All isolates (n317) were tested for resistance
  to TCC and TCS
• CNS isolates from all 3 groups had comparable MIC
  values when tested against TCC and TCS
• SA isolates had comparable MIC values when tested
  against TCC and TCS

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Results

• Antibacterial Resistance
• CNS MIC Values
• TCC TCS
• NU 0.0117-0.750 0.128-2.020
• TCC 0.0234-0.750 0.004-2.020
• TCS 0.0117-0.750 0.008-2.020

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Results

• Antibacterial Resistance
• SA MIC Values
• TCC TCS
• NU 0.0469-0.1875 0.510-2.040
• TCC 0.0029-0.1875 0.124-1.020
• TCS 0.0469-0.1875 1.020-2.040

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Results

• Cross-Resistance Testing
• CNS 9 isolates most resistant to preferred
  treatment drugs (4-5)
• Antibacterial MICs for TCC were comparable across
  all 3 groups, with none showing highest MICs (as
  did less antibiotic-resistant isolates)
• MICs for TCS were comparable, and with one
  exception, none showed highest MICs (as did less
  antibiotic-resistant isolates)

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Results

• Cross-Resistance Testing
• CNS 7 isolates w/highest antibacterial MICs for
  TCC
• Comparable antibiotic resistance across the 3
  groups (resistance to 0-2 preferred drugs), as
  opposed to resistance to 4-5 drugs shown by less
  TCC-resistant isolates.

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Results

• Cross-Resistance Testing
• CNS 60 isolates w/highest antibacterial MICs
  for TCS
• Comparable antibiotic resistance across the 3
  groups, as opposed to resistance to drugs shown
  by less TCS-resistant isolates.

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Results

• Cross-Resistance Testing
• SA
• No isolates showing highest possible MIC value
  for TCC.
• Of 3 isolates showing the highest MIC value for
  TCS, none were resistant to any of the preferred
  treatment drugs.

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Conclusion

• These study results confirm similar findings from
  recent assessments of antibiotic and
  antibacterial resistance in home environments
• Cole et al, J Appl Micro 2003 Aiello et al, Emer
  Inf Dis 2005

27
Conclusion

• These study results further discount the
  speculative claim that the use of antibacterial
  wash products contribute to the selection and
  propagation of drug-resistant bacteria on human
  skin.

28
References

• Cole et al, 20003, Investigation of antibiotic
  and antibacterial agent cross-resistance in
  target bacteria from homes of antibacterial
  product users and non-users. Journal of Applied
  Microbiology 95664-676.
• Aiello et al, 2005, Antibacterial cleaning
  products and drug resistance. Emerging Infectious
  Diseases, 11(10)1565-1570.
• DUMC (2005), Summary of Antimicrobial
  Susceptibility Test Results 1999-2004, Duke
  University Medical Center, Durham, NC,
  htpp//pathology.mc.duke.edu/microbiology/suscepti
  bility.htm.
• Fridkin SF, Hill HA, Volkova NV, Edwards JR,
  Lawton RM, Gaynes RP, McGowan , Jr JE, 2002,
  Temporal changes in prevalence of antimicrobial
  resistance in 23 U.S. hospitals, Emerging
  Infectious Diseases, (8)7697-701.
• Tiemersma EW, Bronzwaer SL, Lyytikainen O,
  Degener JE, Schrijnemakers P, Bruinsma N, Monen
  J, Witte W, Grundmann H, 2004,
  Methicillin-resistant Staphylococcus aureus in
  Europe, 1999-2002, Emerging Infectious Diseases,
  10(9)1627-1634.