Bacterial contamination of stethoscopes with antimicrobial diaphragm covers

Respiratory Therapy Department, Saint Alphonsus Regional Medical Center, Boise, ID 83706, USA.
American Journal of Infection Control (Impact Factor: 2.33). 06/2007; 35(4):263-6. DOI: 10.1016/j.ajic.2006.09.004
Source: PubMed

ABSTRACT Antimicrobial stethoscope covers impregnated with silver ions have been developed to prevent surface contamination and potential transmission of bacterial pathogens to patients. To test their practical utility, covers were distributed with the manufacturers' recommendations to a mixed group of health care professionals in a medical/surgical intensive care unit and an emergency department. Seventy-four clinicians were selected from a convenience sample for surface cultures and standard questioning regarding cleaning and cover use. Surface colony counts were significantly lower for uncovered stethoscope diaphragms (mean, 71.4 colonies) compared with covers used <or=1 week (mean, 246.5 colonies) and those >1 week old (mean, 335.6 colonies). After controlling for type of clinician, frequency of stethoscope cleaning, and method of stethoscope cleaning, only the presence of a stethoscope cover was associated with higher colony counts (P<.0001). We question the practical utility of the antimicrobial diaphragm covers evaluated in this study for reducing the surface colonization of potentially harmful microorganisms.

1 Follower
  • Source
    • "Even though the antibacterial mechanism of silver is still unclear, it has been proposed that it is a combination of the action of silver ions and particles where the smaller the nanoparticle, the biggest the importance of the activity of silver ions [26]. Humidity is a key factor for ion transportation [27] and the drop of efficacy in antibacterial activity is expected in dry environments according to previous reports [11] [28]. Nevertheless, humidity is not only a pathway for ion transportation, it is also a trigger for silver ions generation [29] "
    [Show abstract] [Hide abstract]
    ABSTRACT: Silver nanoparticles synthesized on titanium dioxide (Ag/TiO2), an effective antibacterial additive, were added to a commercial paint and its antimicrobial activity was evaluated. Microbiological tests against Escherichia coli and Methicillin-resistant Staphylococcus aureus were performed under high relative humidity (RH>90%) and low (RH≈14%). A remarkable difference in cell recovery under high and low humidity was found.
    Materials Letters 11/2014; 134:103–106. DOI:10.1016/j.matlet.2014.07.067 · 2.27 Impact Factor
  • Source
    • "The lack of efficacy of silver ion-containing materials was recently verified by Wood et al. (2007) in a hospital setting, which approximates the 24% RH and 20°C test conditions. It was determined that stethoscope protective diaphragm covers, made from silver ion-containing material Ag-A, had a mean colony count of 246AE5 per sample, while the uncovered stethoscopes diaphragms had 71AE4 colonies per sample (Wood et al. 2007). Thus the silver ion-containing protective covers, which were reported to be antimicrobial, were more heavily contaminated than the unprotected stethoscope diaphragms. "
    [Show abstract] [Hide abstract]
    ABSTRACT: To compare silver and copper, metals with known antimicrobial properties, by evaluating the effects of temperature and humidity on efficacy by challenging with methicillin resistant Staphylococcus aureus (MRSA). Using standard methodology described in a globally used Japanese Industrial Standard, JIS Z 2801, a silver ion-containing material exhibited >5 log reduction in MRSA viability after 24 h at >90% relative humidity (RH) at 20 degrees C and 35 degrees C but only a <0.3 log at approximately 22% RH and 20 degrees C and no reduction at approximately 22% RH and 35 degrees C. Copper alloys demonstrated >5 log reductions under all test conditions. While the high humidity (>90% RH) and high temperature (35 degrees C) utilized in JIS Z 2801 produce measurable efficacy in a silver ion-containing material, it showed no significant response at lower temperature and humidity levels typical of indoor environments. The high efficacy levels displayed by the copper alloys, at temperature and humidity levels typical of indoor environments, compared to the low efficacy of the silver ion-containing material under the same conditions, favours the use of copper alloys as antimicrobial materials in indoor environments such as hospitals.
    Letters in Applied Microbiology 04/2009; 49(2):191-5. DOI:10.1111/j.1472-765X.2009.02637.x · 1.75 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The current prevalence of hospital-acquired infections and evolving amplification of bacterial resistance are major public health concerns. A heightened awareness of intraoperative transmission of potentially pathogenic bacterial organisms may lead to implementation of effective preventative measures. Sixty-one operative suites were randomly selected for analysis. Sterile intravenous stopcock sets and two sites on the anesthesia machine were decontaminated and cultured aseptically at baseline and at case completion. The primary outcome was the presence of a positive culture on the previously sterile patient stopcock set. Secondary outcomes were the number of colonies per surface area sampled on the anesthesia machine, species identification, and antibiotic susceptibility of isolated organisms. Bacterial contamination of the anesthesia work area increased significantly at the case conclusion, with a mean difference of 115 colonies per surface area sampled (95% confidence interval [CI], 62-169; P < 0.001). Transmission of bacterial organisms, including vancomycin-resistant enterococcus, to intravenous stopcock sets occurred in 32% (95% CI, 20.6-44.9%) of cases. Highly contaminated work areas increased the odds of stopcock contamination by 4.7 (95% CI, 1.42-15.42; P = 0.011). Contaminated intravenous tubing was associated with a trend toward increased nosocomial infection rates (odds ratio, 3.08; 95% CI, 0.56-17.5; P = 0.11) and with an increase in mortality (95% CI odds ratio, 1.11-infinity; P = 0.0395). Potentially pathogenic, multidrug-resistant bacterial organisms are transmitted during the practice of general anesthesia to both the anesthesia work area and intravenous stopcock sets. Implementation of infection control measures in this area may help to reduce both the evolving problem of increasing bacterial resistance and the development of life-threatening infectious complications.
    Anesthesiology 10/2008; 109(3):399-407. DOI:10.1097/ALN.0b013e318182c855 · 6.17 Impact Factor
Show more


Available from