An investigation aimed at pinpointing the source of a lingering bacterial outbreak in a Toronto hospital turned up an unlikely suspect: the sinks did it.

State-of-the-art handwashing sinks installed in the intensive care unit and some patient rooms in Toronto’s Mount Sinai Hospital actually became the reservoir of a pesky drug-resistant bug that infected or colonized 66 patients from the fall of 2006 to the spring of 2011.