ICU Stethoscopes May Be Vector For Bacterial Infections: Study

The findings of a new study suggests that stethoscopes used in hospital intensive care units (ICUs) are often be covered in bacterial DNA, which could transmit infections between patients. 

Researchers with the University of Pennsylvania Perelman School of Medicine found that more than half of stethoscopes tested at one hospital in Philadelphia were positive for Staphylococcus aureus, which can cause staph infections. In addition, some also tested for pseudomonas and Acinetobacter bacterial contamination.

According to a report published last week in the medical journal Infection Control & Hospital Epidemiology, the findings suggest that stethoscopes could be a vector for hospital-acquired infections.

The study involved gene sequencing on stethoscopes used in an ICU in Philadelphia, including practitioner stethoscopes, those designed for individual use in patient rooms and stethoscopes slated for individual patient use that were clean and had not been used. Researchers also tested two sets of practitioner stethoscopes that had been sampled before and after being cleaned using either standardized procedures or the method preferred by the practitioner who used them.

According to the findings, bacterial contamination was found at its highest levels on practitioner stethoscopes, followed by those assigned to patients’ rooms. Clean stethoscopes which had never been used had the same level of contamination as the background control group.

Researchers noted that the bacteria found on practitioners’ stethoscopes were commonly of the same type linked to healthcare-associated infections, with staph being in the highest abundance. The researchers said the bacteria was nearly ubiquitous on practitioner stethoscopes, and was found on 24 of 40 stethoscopes tested overall.

The study found that cleaning resulted in a significant reduction of bacterial contamination, but the cleanings, regardless of the procedures practitioners used, rarely lowered the level of contamination to those of clean, unused stethoscopes or those in the control group.

“Stethoscopes used in an ICU carry bacterial DNA reflecting complex microbial communities that include nosocomially important taxa,” the researchers concluded. “Commonly used cleaning practices reduce contamination but are only partially successful at modifying or eliminating those communities.”

Hospital Infection Concerns

One major concern about the spread of staph infections is that some have become resistant to certain forms of antibiotics, known as Methicillin-Resistant Staphylococcus aureus (MRSA), they represent a significant threat to ICU patients because they are difficult to treat.

A study last year at VA hospitals found that rates of MRSA have been declining due to better screening, hygiene practices and other infection control measures. According to the findings, MRSA hospital-acquired infections plummeted 87% in intensive care units (ICUs) during that time.

Resistance is spreading beyond MRSA, however. Many other hospital infections that were also once treated with antibiotics are now resistant to those same drugs. Researchers estimate nearly 700,000 people around the world die from drug-resistant bacteria every year. A 2014 British report warned that antibiotic resistant bacteria will cause more than 10 million deaths globally every year by the year 2050, unless drastic measures are taken to mitigate the growing problem.

Other research indicates more than 23,000 Americans die each year from antibiotic resistant bacteria and 2 million become sick due to the so called superbugs every year.