title: Antimicrobial copper alloys decreased bacteria on stethoscope surfaces.
abstract: BACKGROUND
  Stethoscopes may serve as vehicles for transmission of bacteria among patients. The aim of this study was to assess the efficacy of antimicrobial copper surfaces to reduce the bacterial concentration associated with stethoscope surfaces.
  
  
  METHODS
  A structured prospective trial involving 21 health care providers was conducted at a pediatric emergency division (ED) (n = 14) and an adult medical intensive care unit located in tertiary care facilities (n = 7). Four surfaces common to a stethoscope and a facsimile instrument fabricated from U.S. Environmental Protection Agency-registered antimicrobial copper alloys (AMCus) were assessed for total aerobic colony counts (ACCs), methicillin-resistant Staphylococcus aureus, gram-negative bacteria, and vancomycin-resistant enterococci for 90 days.
  
  
  RESULTS
  The mean ACCs collectively recovered from all stethoscope surfaces fabricated from the AMCus were found to carry significantly lower concentrations of bacteria (pediatric ED, 11.7 vs 127.1 colony forming units [CFU]/cm2, P < .00001) than their control equivalents. This observation was independent of health care provider or infection control practices. Absence of recovery of bacteria from the AMCu surfaces (66.3%) was significantly higher (P < .00001) than the control surfaces (22.4%). The urethane rim common to the stethoscopes was the most heavily burdened surface; mean concentrations exceeded the health care-associated infection acquisition concentration (5 CFU/cm2) by at least 25×, supporting that the stethoscope warrants consideration in plans mitigating microbial cross-transmission during patient care.
  
  
  CONCLUSIONS
  Stethoscope surfaces fabricated with AMCus were consistently found to harbor fewer bacteria.
authors.affiliation: Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC. Electronic address: schmidtm@musc.edu.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Schmidt
authors.affiliation: Department of Emergency Medicine, University of New Mexico, Albuquerque, NM.
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Tuuri
authors.affiliation: North Shore-Long Island Jewish Medical Group, North Shore University Hospital, New York, NY.
authors.forename: Arif
authors.initials: A
authors.lastname: Dharsee
authors.affiliation: Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC.
authors.forename: Hubert H
authors.initials: HH
authors.lastname: Attaway
authors.affiliation: Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Fairey
authors.affiliation: Division of Pediatric Emergency Medicine, Medical University of South Carolina Children's Hospital, Charleston, SC.
authors.forename: Keith T
authors.initials: KT
authors.lastname: Borg
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Medical University of South Carolina, Charleston, SC.
authors.forename: Cassandra D
authors.initials: CD
authors.lastname: Salgado
authors.affiliation: North Shore-Long Island Jewish Medical Group, North Shore University Hospital, New York, NY.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Hirsch
mesh_terms: D000497:Alloys / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003300:Copper; D003428:Cross Infection / Q000517:prevention & control; D004203:Disinfection / Q000379:methods*; D004866:Equipment Contamination / Q000517:prevention & control; D006090:Gram-Negative Bacteria / Q000254:growth & development; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000254:growth & development; D011446:Prospective Studies; D019023:Stethoscopes / Q000382:microbiology*; D065507:Vancomycin-Resistant Enterococci / Q000254:growth & development
chemical_list: D000497:Alloys; D000900:Anti-Bacterial Agents; D003300:Copper
keywords: Antimicrobial copper; Health care–associated infections; Infection control; Stethoscopes