Acquisition of multidrug-resistant Serratia marcescens by critically ill patients who consumed tap water during receipt of oral medication.

We describe an outbreak of multidrug-resistant Serratia marcescens infection and colonization involving adults admitted to a surgical intensive care unit. Examination of the outbreak revealed epidemiological evidence that consumption of tap water from a contaminated faucet during receipt of oral medication was the mechanism of S. marcescens acquisition.