Infection hazard from stethoscopes in hospital

Stethoscope hygiene: A legal consideration for cardiologists practicing in a new era of infection control (COVID-19)

The stethoscope is a tool cherished by the field of cardiology and ubiquitous throughout medicine. However, little consideration has been given to its safe usage regarding its potential for pathogenic contamination despite thorough evidence that stethoscopes can harbor pathogens that can be transmitted to patients upon contact. The COVID-19 (SARS-COV-2) pandemic has led to increased infection control vigilance, including toward the stethoscope, as evidenced by a recent increase in literature highlighting stethoscope hygiene/contamination. A consequence of this increase in awareness is that stethoscopes may be implicated in medical malpractice lawsuits as a potential cause of healthcare-associated infections (HAIs). While there is limited evidence demonstrating a direct connection between stethoscope contamination and HAIs, malpractice lawsuits often do not require direct causative evidence. Regardless, efforts should be made to bolster stethoscope hygiene to not only mitigate patient harm, but also prevent providers from potential medical-legal conflicts. The continued relevance and utility of the stethoscope as a rapid, cost-effective diagnostic tool needs to be appropriately balanced with increased hygiene performance. Providers should anticipate increased scientific evidence and patient awareness regarding stethoscope contamination in the post-COVID-19 era.

Persistent Value of the Stethoscope in the Age of COVID-19

The stethoscope has long been at the center of patient care, as well as a symbol of the physician-patient relationship. While advancements in other diagnostic modalities have allowed for more efficient and accurate diagnosis, the stethoscope has evolved in parallel to address the needs of the modern era of medicine. These advancements include sound visualization, ambient noise reduction/cancellation, Bluetooth (Bluetooth SIG Inc, Kirkland, Wash) transmission, and computer algorithm diagnostic support. However, despite these advancements, the ever-changing climate of infection prevention, especially in the wake of the COVID-19 pandemic, has led many to question the stethoscope as a vector for infectious diseases. Stethoscopes have been reported to harbor bacteria with contamination levels comparable with a physician's hand. Although disinfection is recommended, stethoscope hygiene compliance remains low. In addition, disinfectants may not be completely effective in eliminating microorganisms. Despite these risks, the growing technological integration with the stethoscope continues to make it a highly valuable tool. Rather than casting our valuable tool and symbol of medicine aside, we must create and implement an effective method of stethoscope hygiene to keep patients safe.

Blood Pressure Cuff as a Potential Vector of Pathogenic Microorganisms A Prospective Study in a Teaching Hospital

Objective.

To investigate the potential role of blood pressure (BP) cuffs in the spread of bacterial infections in hospitals.

Design.

A comprehensive, prospective study quantitatively and qualitatively evaluating the bacterial contamination on BP cuffs of 203 sphygmomanometers in use in 18 hospital units from January through March 2003.

Setting.

A university hospital with surgical, medical, and pediatric units.

Results.

A level of contamination reaching 100 or more colony-forming units per 25 cm2was observed on 92 (45%) of inner sides and 46 (23%) of outer sides of 203 cuffs. The highest rates of contamination occurred on the inner side of BP cuffs kept in intensive care units (ICUs) (20 [83%] of 24) or on nurses' trolleys (27 [77%] of 35). None of the 18 BP cuffs presumed to be clean (ie, those that had not been used since the last decontamination procedure) had a high level of contamination. Potentially pathogenic microorganisms were isolated from 27 (13%) of the 203 BP cuffs: 20 of these microorganisms wereStaphylococcus aureus, including 9 methicillin-resistant strains. The highest rates of contamination with potentially pathogenic microorganisms were observed on cuffs used in ICUs and those kept on nurses' trolleys. For 4 patients with a personal sphygmomanometer, a genetic link was found between the strains isolated from the BP cuffs and the strains isolated from the patients.

Conclusions.

The results of this survey highlight the importance of recognizing BP cuffs as potential vectors of pathogenic bacteria among patients and as a source of reinfection when dedicated to a single patient, emphasizing the urgent need for validated procedures for their use and maintenance.

Sterile working in ultrasonography: the use of dedicated ultrasound covers and sterile ultrasound gel

Ultrasound is currently an important tool for diagnostic and interventional procedures. Ultrasound imaging provides significant advantages as compared to other imaging methods. The widespread use of ultrasound also carries the risk of drawbacks such as cross-infections. A large body of literature reports this possibly life-threatening side effect and specific patient populations are particularly at risk (e.g., neonates). Various methods of ultrasound probe disinfection are described; however, none of the mechanical or chemical probe disinfection procedures is optimal and, in particular, disinfection with high concentration of alcohol might be associated with ultrasound probe damage. The preparation of ultrasound probes with dedicated probe covers is a useful alternative for sterile working conditions. One ultrasound probe cover discussed in this paper is directly glued on to the ultrasound probe without the use of ultrasound coupling gel. By the use of sterile ultrasound coupling gel at the outer surface, additional effects on aseptic working conditions can be obtained.

Contamination of stethoscopes and physicians' hands after a physical examination

OBJECTIVES

To compare the contamination level of physicians' hands and stethoscopes and to explore the risk of cross-transmission of microorganisms through the use of stethoscopes.

PATIENTS AND METHODS

We conducted a structured prospective study between January 1, 2009, and May 31, 2009, involving 83 inpatients at a Swiss university teaching hospital. After a standardized physical examination, 4 regions of the physician's gloved or ungloved dominant hand and 2 sections of the stethoscopes were pressed onto selective and nonselective media; 489 surfaces were sampled. Total aerobic colony counts (ACCs) and total methicillin-resistant Staphylococcus aureus (MRSA) colony-forming unit (CFU) counts were assessed.

RESULTS

Median total ACCs (interquartile range) for fingertips, thenar eminence, hypothenar eminence, hand dorsum, stethoscope diaphragm, and tube were 467, 37, 34, 8, 89, and 18, respectively. The contamination level of the diaphragm was lower than the contamination level of the fingertips (P<.001) but higher than the contamination level of the thenar eminence (P=.004). The MRSA contamination level of the diaphragm was higher than the MRSA contamination level of the thenar eminence (7 CFUs/25 cm(2) vs 4 CFUs/25 cm(2); P=.004). The correlation analysis for both total ACCs and MRSA CFU counts revealed that the contamination level of the diaphragm was associated with the contamination level of the fingertips (Spearman's rank correlation coefficient, ρ=0.80; P<.001 and ρ=0.76; P<.001, respectively). Similarly, the contamination level of the stethoscope tube increased with the increase in the contamination level of the fingertips for both total ACCs and MRSA CFU counts (ρ=0.56; P<.001 and ρ=.59; P<.001, respectively).

CONCLUSION

These results suggest that the contamination level of the stethoscope is substantial after a single physical examination and comparable to the contamination of parts of the physician's dominant hand.

Factors influencing stethoscope cleanliness among clinical medical students

This study aims to identify current stethoscope hygiene habits and attitudes in a UK medical school setting. Students completed a questionnaire using Likert-scale questions and free-text answers. A total of 308 questionnaires were completed from a potential 750 students (41%); 22.4% of respondents had never cleaned their stethoscope and only 3.9% cleaned their stethoscope after every patient. Significant correlations were identified between cleaning frequency and: others acting as role models (P = 0.001), students having confidence in how to clean stethoscopes (P = 0.001), and students thinking cleaning was important (P = 0.01), thereby highlighting inadequate education and role models as potential problems.

Predictors of stethoscope disinfection among pediatric health care providers

BACKGROUND

Stethoscopes are contaminated with bacteria, but predictors of stethoscope disinfection frequency are unknown. We sought to describe health care provider stethoscope disinfection attitudes and practices and determine predictors of frequent disinfection.

METHODS

We used an anonymous online survey of nurses, nurse practitioners, and physicians at a pediatric hospital. We assessed frequency and methods of disinfection, perceptions of contamination, and barriers to disinfection. Multivariate logistic regression models were used to identify independent predictors of disinfecting after every use.

RESULTS

One thousand four hundred one respondents completed the survey: 76% believed that infection transmission occurs via stethoscopes, but only 24% reported disinfecting after every use. In multivariate analyses, belief that infection transmission occurs via stethoscopes significantly increased the odds of disinfection after every use (odds ratio [OR], 2.06 [95% confidence interval (CI): 1.38-3.06]). The odds of disinfection after every use were significantly decreased in those who perceived the following barriers: lack of time (OR, 0.31 [95% CI: 0.18-0.54]), lack of access to disinfection material (OR, 0.41 [95% CI: 0.29-0.57]), or lack of visual reminders to disinfect (OR, 0.22 [95% CI: 0.14-0.34]).

CONCLUSION

Only a minority of pediatric health care providers reported disinfecting their stethoscopes after every use. Increasing access to disinfection materials and visual reminders in health care facilities may improve stethoscope disinfection practices.

Effects of 'bare below the elbows' policy on hand contamination of 92 hospital doctors in a district general hospital

Despite a lack of evidence the UK's Department of Health introduced a policy of 'bare below the elbows' attire in order to try to reduce the incidence of nosocomial infection. This study investigates the link between this state of dress and hand contamination. A prospective observational study of doctors working in a district general hospital was carried out. The fingertips of each hand were imprinted onto culture medium, and resultant growth assessed for number of colony-forming units and presence of clinically significant pathogens or multiply resistant organisms. These findings were correlated with attire, grade, sex and specialty. Ninety-two doctors were recruited of whom 49 were 'bare below the elbows' compliant and 43 were not. There was no statistically significant difference between those doctors who were 'bare below the elbows' and those that were not, either for the number of colony-forming units or for the presence of clinically significant organisms. No multiply resistant organisms were cultured from doctors' hands. 'Bare below the elbows' attire is not related to the degree of contamination on doctors' fingertips or the presence of clinically significant pathogens. Further studies are required to establish whether investment in doctors' uniforms and patient education campaigns are worthwhile.

Evaluation of dedicated stethoscopes as a potential source of nosocomial pathogens

OBJECTIVE

To determine whether the ear tips of dedicated stethoscopes (DS) that are used on patients prescribed contact precautions for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium, or multiple antibiotic-resistant Acinetobacter baumannii become contaminated with these micro-organisms.

DESIGN

Culture of DS ear tips.

SETTING

A 524-bed tertiary care university hospital.

METHODS

DS ear tips were inoculated directly onto bacteriologic media and incubated for 48 to 72 hours. Growth of more than 10 colonies from the 2 ear tips collectively was indicative of contamination.

RESULTS

Ear tips of 78 DS from 69 patients were cultured. Ear tips from 17% (13/78) of the DS were contaminated with potentially pathogenic bacteria: 2 with S aureus (1 MRSA), 1 with E faecalis, 7 with Acinetobacter species, 2 with Pseudomonas species, 1 with Escherichia coli, and 1 with Moraxella. None of the stethoscope ear tips was contaminated with the same pathogen for which the patient was prescribed contact precautions (95% CI, 0-3.8%).

CONCLUSION

Although the ear tips of DS from patients who were prescribed contact precautions for MRSA, vancomycin-resistant E faecium, or multiple antibiotic-resistant A baumannii were not contaminated with the indicated nosocomial pathogen, 94% of the evaluable ear tips were contaminated, including with MRSA (1.3%) and Acinetobacter (11%). Regular disinfection of ear tips of DS between users should be considered.

Evaluation of the role of ultrasound machines as a source of nosocomial and cross-infection

RATIONALE AND OBJECTIVES

To evaluate the potential role of ultrasonography probes and coupling gel for cross-infection in patients undergoing ultrasonography; to describe a cost-effective method of probe handling; and to emphasize the importance of position of the probes in the boxes.

METHODS

Cultures were taken from 43 probes used in different scanning regions. Cultures were also taken from probe boxes and coupling gel.

RESULTS

After abdominal scanning, cleaning with paper seems to be effective, but even wiping with alcohol is insufficient for inguinal and axillar regions. Before scanning of these areas is started, cleaning the inguinal and axillar regions with alcohol reduces the contamination risk. Placing the probes downward in boxes also increases the risk of contamination.

CONCLUSIONS

Wiping the probes with dry paper seems to be effective only for abdominal scanning; for inguinal and axillar scanning, cleaning the region with alcohol before scanning seems more appropriate. Placing the probes downward in boxes may also be a source of contamination.

Lapses in measures recommended for preventing hospital-acquired infection

This study was carried out in a rural tertiary care referral hospital in central India, to ascertain lapses made by people caring for neonates in measures recommended for preventing hospital-acquired infections. Unobtrusive observation of the healthcare personnel (doctors, nurses, mothers and hospital attendants) during care of the newborn was undertaken. Lapse in handwashing by healthcare personnel was observed around 41% of the time, although mothers practiced their instructions meticulously. Lapses in methods of hand drying were seen around 7-8% of the time, in those who did wash their hands. Gloves were not used around 21% of the time, when they should have been; and of those using gloves, they were unsterile in around 22% cases. At delivery babies were received unhygienically on approximately 67% of occasions observed. Lapses during cord care ranged from 14.2% to 28.6% and during resuscitation from 16.6% to 60% of occasions. An uncleaned stethoscope was used 75% of the time. The practice of putting a finger in the baby's mouth was observed on 18 occasions. Considerable lapses by all, in every measure recommended for the prevention of hospital-acquired infections were observed. It is concluded that nothing other than an individual's commitment is likely to be successful in preventing hospital-acquired infections.

Organic buildup and residual blood on infant stethoscopes in maternal-infant areas

OBJECTIVE

To identify the presence of residual blood and organic matter on "clean" stethoscopes in maternal-infant units.

DESIGN

In this retrospective, nonexperimental study, stethoscopes were tested using qualitative measurements.

SETTING

Using a nonprobability sampling technique, 11 acute care hospitals in a three-state area of the southwestern United States were studied.

PARTICIPANTS

All stethoscopes found on the maternal-infant units were included, for a total sample size of 97.

INSTRUMENTS

A hand-held 10-power lens was used to visually rank the amount of organic buildup, and the phenolphthalein test was used to detect residual blood on the stethoscope.

RESULTS

Of 97 clean infant stethoscopes, 80% of labor and delivery and 72% of nursery stethoscopes had organic buildup on the diaphragm. Both areas had similar rates of organic buildup, chi2 (1, N = 97) = 1.00, p = ns. Nursery areas did have significantly lower rates of residual blood than stethoscopes from labor and delivery, phi2 (1, N = 97) = 9.89, p = .002. Seventy-six percent of labor and delivery stethoscopes were positive for blood, as compared to 46% of nursery stethoscopes.

CONCLUSIONS

Traditional methods for cleaning stethoscopes used in labor and delivery and nursery areas are ineffective in removing blood and other body fluids from the stethoscope.

Stethoscopes: a potential vector of infection?

STUDY OBJECTIVES

To survey emergency care providers about their stethoscope-cleaning measures and to determine the correlation between these measures and the extent of Staphylococcus carriage.

DESIGN

Prospective cross-sectional analysis.

SETTING

University-affiliated community hospital ED.

PARTICIPANTS

One hundred fifty health care providers, comprising emergency medicine house staff and attending physicians (n = 50), ED nurses (n = 50), and prehospital personnel working in Kent County, Michigan (n = 50).

INTERVENTIONS

Providers were asked how often they cleaned their stethoscopes and which cleaning agents were used. We then cultured each stethoscope by pressing the diaphragm on mannitol agar and incubating the culture aerobically for 48 hours. Staphylococcus aureus was identified by means of standard measures. We examined the effects of different cleaning agents on 24 stethoscopes. The numbers of colony-forming units (CFUs) before and after cleaning with alcohol, nonionic detergent, and antiseptic soap were noted.

RESULTS

Overall, 48% of health care providers (74 of 150) cleaned their stethoscopes daily or weekly, 37% monthly, and 7% yearly; and 7% had never cleaned their stethoscopes. No significant differences were found in the hygiene routines of the three groups of providers surveyed. Use of an alcohol swab was the preferred method of cleaning. One hundred thirty-three stethoscopes (89%) grew staphylococci; 25 (19%) yielded S aureus. Mean staphylococcal bacterial counts ( +/- SD) were 52 +/- 78 CFUs per stethoscope among physicians, 46 +/- 92 CFUs among emergency medical service personnel, and 13 +/- 21 CFUs from the nursing staff (ANOVA, P = .01). Cleaning the stethoscope diaphragm resulted in immediate reduction in the bacterial count: by 94% with alcohol swabs, 90% with nonionic detergent, and 75% with antiseptic soap.

CONCLUSION

Our results confirm that stethoscopes used in emergency practice are often contaminated with staphylococci and are therefore a potential vector of infection. This contamination is greatly reduced by frequent cleaning with alcohol or nonionic detergent.

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Stethoscopes as possible vectors of infection by staphylococci

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The microbial flora of in-use blood pressure cuffs

The capacity of blood pressure cuffs to act as vehicles of hospital infection has been recognised. We describe the microbial flora of in-use DINAMAP blood pressure cuffs used in the operating theatres and one recovery room in a teaching hospital. Our results show significant microbial contamination of in-use blood pressure cuffs.

Adhesive tape: potential source of nosocomial bacteria

During a 7-day period, a variety of bacteria, including opportunistic ones, were recovered from 23 rolls of adhesive tape being used in a 16-bed intensive care unit. All rolls of tape were sterile when received from the manufacturer. Mixed flora was recovered from a total of 15 rolls, whereas eight rolls yielded pure cultures. Organisms recovered included Staphylococcus aureus, Pseudomonas aeruginosa, and various species of Enterobacteriaceae. Although no illness or infection arising directly from contaminated adhesive tape has been documented, we feel that a potential source of infection has been identified. Most important is the fact that such tape may contaminate the hands of personnel who handle it. Also, the adhesive tape may directly contaminate a patient since it is widely used to secure artificial airways and various drainage tubes which results in the tape coming into close contact with the mucous membranes lining the patient's respiratory and urogenital tracts.