Hospital Superbug Infections May Be Spread Through Sink Drains, Plumbing: Study

Drug-resistant bacteria found in the drains of hospital sinks may pose a serious risk of causing “superbug” infection outbreaks, according to the findings of new research. 

In a study published last week in the journal Applied and Environmental Microbiology, researchers warn that superbugs may be breeding in hospital sinks and plumbing, endangering patients and healthcare professionals.

Researchers from the University of Virginia Health System wanted to explore the increasing numbers of bacteria resistant infections at hospitals nationwide, which may stem from sink drains. They conducted experiments to replicate how bacteria grows in hospital plumbing.

The study used E.coli instead of more harmful antibiotic resistant bacteria. E.coli grows similarly to other harmful bacteria, like Klebsiella, which was associated with an outbreak at a National Institutes of Health (NIH) Clinical Center in 2012 that killed 11 patients. Researchers genetically engineered the E.coli to glow green under fluorescent lights.

Bacteria live in much of the slimy, black goo found at the bottom of the drain. Experts initially believed drug resistant bacteria, or superbugs, multiplied in the “U” shaped trap that holds water. However,  the new study revealed that bacteria grew up the pipes into the drain, and a thin, but durable biofilm formed. The film is difficult to scrape off and even more difficult to kill with chemicals.

The findings indicate that the bacteria may splash out into sinks and onto counters. In water splash experiments, bacteria stay attached to the pipe and wasn’t washed away with water. However, it splashed up to two feet out of the sink when water was run. Researchers said the bacteria can also thrive in connections with wastewater plumbing to neighboring sinks.

The study raises serious concerns, as an increase in sink-related outbreaks has been seen worldwide. One study indicated one-in-seven hospital acquired infections involved antibiotic resistant bacteria.

The first thing doctors, nurses and other healthcare professionals do when entering a patient’s room is wash their hands. The findings suggest that this may put them in a prime area to become contaminated and spread infection to other people.

A study published last year indicated hospital patients are often a significant source of antibiotic-resistant bacteria, which are then transmitted to other patients. More than one-third of patients entering hospitals were colonized with multiple forms of antibiotic-resistant bacteria.

Other research teams tried attacking the bacteria by pouring bleach down the drains and heating the pipes. None of the measures tried were able to kill the bacteria.

Researchers said this shows the importance of sink design. Moving the placement of the faucet can prevent the water from landing in the drain, which in turn may help prevent the splash out.

The NIH outbreak was eventually mitigated after sink traps were taken apart and removed. The biofilm was scrubbed off with wire brushes and bleach. The sinks were treated on a daily basis with spray bleach. In some cases, the sinks had to be replaced.

Researchers warn infections caused by antibiotic resistant bacteria are more widespread than believed. Superbug infections sicken more than 2 million people each year, costing nearly $35 billion in lost productivity and sick days. More than 722,000 people got infections while in the hospital in 2011, 75,000 died as a result.