Nosocomial Serratia marcescens individualized by five typing methods in a regional hospital.

The relationships between 69 isolates obtained from 26 patients who were affected by two Serratia marcescens hospital outbreaks occurring in the urology and postnatal wards, were examined by five typing methods for epidemiological purposes. Serotyping, antibiotic resistance profile and electrophoretic analysis of enzymes identified three groups of isolates, while biotyping and bacteriocin typing identified only two. These surveys allowed us to demonstrate the existence of independent episodes of cross-infection among patients of each ward.