For generations, doctors have used—and sanitized—their stethoscope without issue. Today, however, with the advent of antibacterial-resistant bugs, doctors are finding it a challenge to keep their diagnostic tools clean. A study published in Mayo Clinic Proceedings highlights the issue: a random sampling of stethoscopes contained as much bacteria as the palms of their operators’ hands. Unless doctors carefully sanitize the diaphragm of their stethoscopes, they can become vectors of disease themselves.
Researchers have even found the highly resistant strain Staphylococcus aureus on stethoscope diaphragms and tubes. Strains like these respond poorly to chemical processes meant to neutralize them. Because bacteria multiply so quickly, they undergo evolution at a much higher rate than multicelled organisms. Most resistance develops because random mutations change the arrangement and number of proteins on the cell wall. For instance, the protein transpeptidase is essential for bacterial reproduction. Penicillin works by deactivating this protein. However, the heavy worldwide use of this antibacterial has caused some strains to adapt so that they can successfully metabolize it.
You can minimize risk by asking your doctor to sanitize his hands and stethoscope before examining you. Most doctors rely on alcohol to sanitize their stethoscopes because bacteria are unlikely to form a resistance to it. This is because alcohol kills bugs by causing their cell walls to rupture. Generally, in order to develop a resistance to a substance, an organism must live long enough to metabolize it and reproduce.
Still, alchohol is not a perfect solution. The diaphragm of the stethoscope provides ample hiding places for minute bacteria. Survivors of the alcohol deluge go on to reproduce as normal because alcohol evaporates very quickly. This makes it possible for you to be exposed to bacteria from other patients as doctors typically use the same stethoscope throughout the day.
Other Cleaning Methods and Preventative Measures
Some hospitals use stethoscope disinfection cabinets to eradicate every living organism on their stethoscopes. These cabinets work by pumping ozone through the chamber via fans. Stethoscopes are hung on hooks and never touch, thus preventing cross-contamination. This method of sanitization is very effective, albeit inefficient. The chamber must be sealed so that the ozone can concentrate. The chamber does have one definite advantage: because the sanitizing agent is a gas, every square inch of the stethoscope is sanitized.
In addition to heavy alcohol use, some doctors safeguard their patients by using disposable stethoscopes. These models provide doctors and nurses serviceable acoustic quality, and they’re constructed of inexpensive materials. After a few months, once the stethoscope has accumulated the oils and skin cells that are associated with regular stethoscope use, the doctor disposes of it. This protects patients from bacteria that colonize the nooks and crannies that alcohol can’t reach.
In light of recent research detailing how filthy stethoscopes really are, a slew of sanitization devices are coming on the market that offer a unique solution: easily kill bacteria with light. Short-wave ultraviolet light kills bacteria by destroying acids within the nucleus. This critically damages the cell’s organelles, which renders them inert. While UVGI doesn’t kill bacteria as quickly as alcohol does, it is even more effective at reaching every nook and cranny than gas is, and it guarantees that the bacteria present will not be able to reproduce. Bacteria—even deadly strains—are relatively harmless in low numbers as they typically cause disease by releasing metabolic byproducts into the blood.
UVGI is an exciting technology because it can be fitted into every examination room and can render stethoscope diaphragms safe instantaneously. As with alcohol, UVGI-powered devices have been rated 99.9% effective in killing bacteria.