In the News: Serratia marcescens

A contaminated IV fluid is being investigated as the cause of deaths of nine patients in a Montgomery, Alabama, hospital. The infections were found in 19 patients receiving Temporary Perentral Nutrition (TPN), which is a liquid nutrition that feeds the patient. Nine of the 19 patients involved have died, health officials have not determined if the deaths were due to the contaminated product at this point. Serratia marcenscens cannot be transmitted from person to person so there is no threat to patients who were not receiving TPN. The company producing the TPN, has stopped production at this time.

Serratia marcescens is a Gram-negtive, bacterium in the Enterobacteriaceae family. Serratia can cause healthcare associated infections, particularly catheter-associatedd bacteremia (bloodstream infection), urinary tract infections, wound and eye infections. It is noted to be responsible for 1.4% of healthcare associated bacteremia cases in the United States. Serratia is commonly found in the respiratory and urnary tracts of hospitalized adults and the gastrointestinal system of children. Most S. marcescens strains are resistant to several antibiotics such as ampicillin, macrolides, and first-generation cephalosporins (such as cefalexin).

It is commonly found growing in bathrooms, especially on tile grout, shower corners, toilet water lines, and basins. It appears as a pink discoloration and slimy film which feeds off of fatty substances such as soap and shampoo residue. Complete eradication of the organism is difficult, but an application of a bleach based disinfectant can help. S. marcescens can be found in environments such as dirt, and in subgingival biofilm of teeth.

Serratia marcescens was discovered in 1819 by the Venetian pharmacist Bartolomeo Bizio. It was thought to ba a non-pathogenic bacteria until the 1950’s. Since than it has been implicated in many outbreaks. To learn more about outbreaks with Serratia go to