An unusual multidrug-resistant bacterium lurked in sinks at the National Institutes of Health’s Clinical Center for more than a decade, striking at least a dozen patients, a new report by NIH scientists concludes.

Researchers tracked the superbugs to sinks in patient rooms amid a freaky outbreak in 2016. Searching through genetic sequences of clinical samples collected as far back as 2006—a year after a new inpatient hospital building opened—researchers identified eight other cases for a total of 12 instances where the sink-dwelling germs had splashed into patients.

The aquatic germ in these cases was Sphingomonas koreensis. Such sphingomonas species are ubiquitous in the environment but rarely cause infections. In the NIH patients, however, they were found to cause a variety of problems, including pneumonia, blood infections, a surgical site infection, and a potential urinary tract colonization. Some isolates were resistant to 10 antibiotics tested, spanning three classes of drugs.