What Is Lurking in Hospital’s Plumbing?

Scary antibiotic-resistant bacteria appear to be thriving in hospital plumbing, according to a new report (Weingarten et al, mBio, Feb. 6, 2018). The research was conducted in a hospital run by the National Institutes of Health. Over two years, the scientists took microbial samples of sinks, high-touch surfaces, housekeeping closets, wastewater pipes inside the hospital and manholes exterior to the hospital.

What Scientists Found in the Hospital Plumbing:

The investigators discovered that the places that patients are most likely to touch, such as bedrails and countertops, were not often contaminated with antibiotic-resistant bacteria. Only 1.7 percent of those samples carried carbapenem-resistant bacteria. However, three percent of the samples from drains had such bacteria that are not vulnerable to last-resort antibiotics.

Samples from pipes beneath the intensive care unit and from manholes outside on the sewers serving the hospital did carry such bacteria. In such an environment, bacteria trade genetic material, so some germs can pick up resistance even though they’ve never been exposed to antibiotics.

The investigators report:

Strikingly, despite a very low prevalence of patient infections with blaKPC-positive organisms, all samples from the intensive care unit pipe wastewater and external manholes contained carbapenemase-producing organisms (CPOs), suggesting a vast, resilient reservoir.”

Why Worry about Bugs in the Plumbing?

The concern is that some bacteria might splash out of drains and cause contamination.  In addition, they hang out in mops and buckets in janitors’ closets. Consequently, even though they pose little risk to healthy people, they could be dangerous for hospitalized patients whose immune systems are weakened. In fact, the ultra-careful surveillance from this study detected one hospital-acquired infection that was traced to buckets and mops. The researchers warn that similar problems are likely in other hospitals that have not conducted such careful studies.