Why, when and how to clean stethoscopes

Hospital Physicians’ Stethoscopes: Bacterial Contamination After a Simple Cleaning Protocol

BACKGROUND

Stethoscope surfaces become contaminated with bacteria due to inconsistent cleaning practices,​ as​​ ​​​​cleaning frequency and practical clean​s​ing approaches are not well-established.

METHODS

We investigated bacterial contamination of stethoscopes at baseline, after simple cleaning, and after examining one patient. We surveyed 30 hospital providers on stethoscope cleaning practices and then measured bacterial contamination of stethoscope diaphragm surfaces before cleaning, after cleaning with alcohol-based hand sanitizer, and after use in examining one patient.

RESULTS

Only 20% of providers reported cleaning stethoscopes regularly. Before cleaning, 50% of stethoscopes were contaminated with bacteria, compared with 0% after cleaning (p<0.001) and 36.7% after examining one patient (p=0.002). Among providers who reported not cleaning stethoscopes regularly, 58% had bacterial-contaminated stethoscopes compared with 17% who did report cleaning regularly (p=0.068).

CONCLUSIONS

Hospital providers' stethoscopes had a high probability of bacterial contamination at baseline and after examining one patient. We recommend decontamination with alcohol-based hand sanitizer immediately before each patient examination.

Methods of Disinfecting Stethoscopes: Systematic Review

The aim of this systematic review was to investigate the effectiveness of various disinfection methods available for stethoscopes. In March 2019, we performed a search in PubMed and Scopus using the search terms: "reducing stethoscopes contamination" and "disinfection stethoscopes"; the Mesh terms used in PubMed were "Decontamination/methods" or "Disinfection/methods" and "Stethoscopes/microbiology". Selection criteria were: English language; at least one disinfection method tested. A total of 253 publications were screened. After title, abstract, and full-text analysis, 17 papers were included in the systematic review. Ethanol at 90%, Ethanol-Based Hands Sanitizer (EBHS), triclosan, chlorhexidine, isopropyl alcohol, 66% ethyl alcohol, sodium hypochlorite, and benzalkonium chloride have been proven to lower the presence of bacteria on stethoscopes' surfaces. In addition, alcohol wipes show effective results. A wearable device emitting ultraviolet C by Light-Emitting Diode (LED) resulted efficacious against common microorganisms involved in Healthcare Associated Infections. The cover impregnated with silver ions seemed to be associated with significantly higher colony counts. Instead, copper stethoscopes surface reduced bacterial load. The disinfection of stethoscopes appears to be essential. There are many valid methods available; the choice depends on various factors, such as the cost, availability, and practicality.

Contemporary stethoscope cleaning practices: What we haven't learned in 150 years

BACKGROUND

Stethoscopes can be microorganism reservoirs. The US Centers for Disease Control and Prevention (CDC) has published medical equipment disinfection guidelines to minimize infection transmission risk, but studies of guideline adherence have been predominately survey based, with little direct observation of disinfection practices.

METHODS

We performed an observational, cross-sectional, anonymous study of patient-provider interactions, assessing practitioners' frequency and methods of stethoscope and hand disinfection practices.

RESULTS

Stethoscopes were disinfected in 18% of 400 observed interactions, with less than 4% verified as conforming to CDC guidelines. None was disinfected before patient examinations involving open chest or abdominal wounds, as recommended by the CDC. Hands were cleaned before and after encounters 27 times (6.8%) but were not cleaned at all in 231 (58%) encounters, although gloves were worn in 197 (85.3%) of these cases.

DISCUSSION

Stethoscope disinfection is grossly overlooked, possibly jeopardizing patient safety, particularly in acute care interactions. Periodic stethoscope disinfection, although inconvenient, helps reduce bacterial contamination and may reduce health care-associated infections.

CONCLUSIONS

Stethoscopes were disinfected per CDC guidelines in less than 4% of encounters and were not disinfected at all in 82% of encounters. Although hands were rarely cleaned (6.8%) per CDC guidelines, gloves were usually worn, but no convenient stethoscope equivalent exists. Stethoscope cleanliness must be addressed.

The stethoscope and healthcare-associated infection: a snake in the grass or innocent bystander?

There is a concern that stethoscopes may transmit infectious agents which could result in healthcare-associated infection (HCAI). The aim of this review was to evaluate the available literature as to the role of the stethoscope in the development of HCAI. A literature search was conducted across several databases for relevant studies and reports. Stethoscopes were consistently shown to harbour bacteria. The mean rate of stethoscope contamination across 28 studies was 85% (range: 47-100%). The majority of bacteria isolated were deemed to be non-pathogenic. The most frequently isolated organisms were coagulase-negative staphylococci. The mean level of contamination was in excess of the French Normalization standard for cleanliness (which equates to <20 colony-forming units per membrane) in all six studies in which contamination levels were quantified. Potentially pathogenic organisms cultured from stethoscopes included: Staphylococcus aureus, Pseudomonas aeruginosa, vancomycin-resistant enterococci, and Clostridium difficile. There was evidence that bacteria can transfer from the skin of the patient to the stethoscope and from the stethoscope to the skin. However, studies were not designed to detect a correlation between stethoscope contamination and subsequent HCAI. Surveys assessing cleaning practices revealed a suboptimal commitment to stethoscope disinfection among doctors and medical students. The optimum method for stethoscope cleaning has not been defined, although alcohol-based disinfectants are effective in reducing bacterial contamination. In conclusion, a link between contaminated stethoscopes and HCAI has not yet been confirmed, but transfer of bacteria between skin and stethoscope has been shown. The available information would suggest that stethoscopes should be decontaminated between patients.

Role of MRSA reservoirs in the acute care setting

Background  Nosocomial infection remains the most common complication of hospitalisation. Despite infection control efforts, nosocomial methicillin-resistant Staphylococcus aureus (MRSA) transmission continues to rise. The associated costs of increased hospital stay and patient mortality cause considerable burden to the health system. Objectives  This review sought to evaluate the role of reservoirs, particularly the environment and equipment commonly found in the clinical area, in the transmission of MRSA within the acute hospital. This review updates a review previously completed by the authors and published by the Joanna Briggs Institute (2002). Search strategy  A systematic search for relevant published or unpublished literature was undertaken using electronic databases, the reference lists of retrieved papers and the Internet. This extended the search published in the original review. Databases searched included  Medline (1966-August Week 1 2005), CINAHL (1982-August Week 1 2005), EMBASE (1996-Week 33), as well as the Cochrane Library (Issue 3, 2005) and the Joanna Briggs Institute Evidence Library (August 2005). Selection criteria  All research reports published between 1990 and August 2005 in the English language that focused on the role of the environment and equipment commonly found in the clinical area on the nosocomial MRSA transmission in adult, paediatric or neonatal acute care settings were considered. Data collection and analysis  Two reviewers assessed each paper against the inclusion criteria and a validated quality scale. Studies that scored less than the mean quality score were excluded from the review. Data extraction was undertaken using a tool designed specifically for this review. Statistical comparisons of findings were not possible, so findings are presented in a narrative form. Results  Forty-two papers met the review inclusion criteria, of which 18 obtained a quality score above the threshold and are included in this review. Seven studies reported general investigations of MRSA in the clinical environment and 11 studies explored specific environmental aspects. All studies used exploratory, descriptive or comparative designs. The evidence suggests that MRSA strains within the environment often match those found in patients within that environment. MRSA can be found in the air around MRSA colonised or infected patients. The degree of airborne contamination is significantly increased by activities that promote airflow. Although the site of MRSA colonisation or infection can influence the degree of environmental contamination, these data are inconsistent. Therefore, there is limited evidence for tailoring infection control interventions based on the sites of MRSA colonisation or infection. The evidence suggests that the type of materials used in clinical equipment can influence the effectiveness of cleaning techniques. Current routine cleaning practices, including conventional terminal cleaning, do not necessarily effectively eradicate MRSA from the environment. This review demonstrates that there is a link between the environment and hospital equipment and the transmission of MRSA within the acute hospital setting. Further well-designed research is urgently required to explore the efficacy of specific cleaning and decontamination methods, staff compliance with infection control practices and the range of factors that affect the incidence of MRSA contamination of the environment and equipment commonly found in the clinical area.

Ethanol-based cleanser versus isopropyl alcohol to decontaminate stethoscopes

Approximately 1 in 20 hospital admissions is complicated by a health care-associated infection. Stethoscopes may play a role in spreading nosocomial infections. The objective of this study was to determine the effectiveness of an ethanol-based cleanser (EBC) compared with isopropyl alcohol pads in reducing bacterial contamination of stethoscope diaphragms. Stethoscopes were cultured from medical professionals on 4 medical floors before and after cleaning with either EBC or isopropyl alcohol pads. The numbers of colony-forming units (cfu) grown were compared between the 2 cleaners and to baseline values. A total of 99 stethoscopes were cultured (49 EBC; 50 isopropyl alcohol), and all were positive for growth. After cleaning, 28.28% of the stethoscopes were growth-free (12 EBC; 16 isopropyl alcohol). Cleaning with EBC and isopropyl alcohol pads significantly reduced the cfu counts (by 92.8% and 92.5%, respectively), but neither was found to be statistically superior (F = 1.22; P = .2721). Cleaning a stethoscope diaphragm using either EBC or isopropyl alcohol led to a significant reduction in bacterial growth in culture. As an extension of the hand, a stethoscope should be cleaned with the same frequency as the hands. The simultaneous cleaning of hands and stethoscope may further increase compliance with current standards.

Role of MRSA reservoirs in the acute care setting

BACKGROUND

Nosocomial infection remains the most common complication of hospitalisation. Despite infection control efforts, nosocomial methicillin-resistant Staphylococcus aureus (MRSA) transmission continues to rise. The associated costs of increased hospital stay and patient mortality cause considerable burden to the health system.

OBJECTIVES

This review sought to evaluate the role of reservoirs, particularly the environment and equipment commonly found in the clinical area, in the transmission of MRSA within the acute hospital. This review updates a review previously completed by the authors and published by the Joanna Briggs Institute (2002).

SEARCH STRATEGY

A systematic search for relevant published or unpublished literature was undertaken using electronic databases, the reference lists of retrieved papers and the Internet. This extended the search published in the original review.Databases searched included Medline (1966-August Week 1 2005), CINAHL (1982-August Week 1 2005), EMBASE (1996-Week 33), as well as the Cochrane Library (Issue 3, 2005) and the Joanna Briggs Institute Evidence Library (August 2005).

SELECTION CRITERIA

All research reports published between 1990 and August 2005 in the English language that focused on the role of the environment and equipment commonly found in the clinical area on the nosocomial MRSA transmission in adult, paediatric or neonatal acute care settings were considered.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed each paper against the inclusion criteria and a validated quality scale. Studies that scored less than the mean quality score were excluded from the review. Data extraction was undertaken using a tool designed specifically for this review. Statistical comparisons of findings were not possible, so findings are presented in a narrative form.

RESULTS

Forty-two papers met the review inclusion criteria, of which 18 obtained a quality score above the threshold and are included in this review. Seven studies reported general investigations of MRSA in the clinical environment and 11 studies explored specific environmental aspects. All studies used exploratory, descriptive or comparative designs. The evidence suggests that MRSA strains within the environment often match those found in patients within that environment. MRSA can be found in the air around MRSA colonised or infected patients. The degree of airborne contamination is significantly increased by activities that promote airflow. Although the site of MRSA colonisation or infection can influence the degree of environmental contamination, these data are inconsistent. Therefore, there is limited evidence for tailoring infection control interventions based on the sites of MRSA colonisation or infection. The evidence suggests that the type of materials used in clinical equipment can influence the effectiveness of cleaning techniques. Current routine cleaning practices, including conventional terminal cleaning, do not necessarily effectively eradicate MRSA from the environment. This review demonstrates that there is a link between the environment and hospital equipment and the transmission of MRSA within the acute hospital setting. Further well-designed research is urgently required to explore the efficacy of specific cleaning and decontamination methods, staff compliance with infection control practices and the range of factors that affect the incidence of MRSA contamination of the environment and equipment commonly found in the clinical area.