An unusual multidrug-resistant bacteria has been lurking in sinks at the National Institutes of Health’s Clinical Center for more than a decade, affecting at least a dozen patients, a new report from NIH scientists concludes.
Researchers tracked the superbugs to sinks in patient rooms during a freaky outbreak in 2016. While searching genetic sequences from clinical samples collected as early as 2006 — a year after a new hospital building opened — researchers identified eight other cases for a total of 12. cases where the sink-living germs were splashed into patients.
The water germ in these cases was Sphingomonas koreensis. Such an sphingomonas species are ubiquitous in the environment, but rarely cause infections. However, in the NIH patients, they were found to cause a variety of problems, including pneumonia, blood infections, a surgical site infection, and possible colonization of the urinary tract. Some isolates were resistant to 10 antibiotics tested, spanning three classes of drugs.
Three of the 12 affected patients died after their infection. However, all of them also suffered from serious, unrelated infections prior to exposure to the sink-based germs, the NIH researchers note.
Their report, recently published in the New England Journal of Medicine, points to the murky problem of opportunistic, often drug-resistant pathogens endangering vulnerable patients by lurking in hospitals — and hospital sinks in particular. As Ars has previously reported, superbug-spewing pits have been caught in several hospital outbreaks over the years. In 2017, researchers published a smashing study showing that dangerous germs can survive in sink P-traps, climb pipes using creeping films and launch onto touchable surfaces with a tap firecracker.
That particular plumbing hazard wasn’t the issue in the NIH’s case, though. After examining a variety of potential sources, including ice machines and the municipal inlet pipe for the hospital, researchers found that the germs crept into sink faucets and fixtures — not sink drains.
Dismantling dismantled sinks, researchers found S. koreensis which inhabit nine sanitary parts, including the faucet, aerators and mixers. The researchers had several faucets replaced, but found they were recolonized soon after, likely via shared contaminated water supply lines between sinks. Ultimately, the researchers seemed to rid the sinks of the dangerous invaders by increasing the hot water temperature and chlorine concentrations for the hospital.
Overall, the researchers suspect that “a single” S. koreensis tension entered the water system shortly after the construction of the new NIH Clinical Center hospital building in 2004” and colonized pipes before the hospital opened, while water stagnated in the pipes. Then “the germ spread throughout the hospital and spread to multiple different locations,” causing a sporadic, decade-long clonal outbreak.
The outbreak isn’t the first for the NIH’s unique clinical research center, which aims to treat rare and intractable diseases with innovative drugs. In 2011, the center was hit by an outbreak of another superbacter, carbapenem-resistant K. pneumoniae, which affected 18 patients, 11 of whom died. A case of fungal infection at the hospital in 2015 prompted a leadership review. An independent review found that patient safety in the hospital had “become subordinate to research requirements”.
Still, the authors of the new study note that the threat of S. koreensis is not unique to the NIH hospital, regardless of its struggle. And they note that the “steps taken in this study to further S. koreensis infections within the NIH Clinical Center are applicable to many opportunistic waterborne pathogens.”
New England Journal of Medicine2018. DOI: 10.156/NEJMoa1803238 (About DOIs).