EPIDEMIOLOGIC SURVEY OF AN OUTBREAK OF MULTIRESISTANT SERRATIA-MARCESCENS BY PCR-FINGERPRINTING

During an outbreak of Serratia marcescens from May to November 1993 43 strains obtained from 27 ICU patients infected or colonized with mult iresistant S. marcescens were genotypically characterized with random amplified polymerase chain reaction (RAPD-PCR)-fingerprinting. In addi tion, 43 epidemiologically unrelated control isolates were selected. P CR-fingerprinting identified ten different genotypes of S. marcescens among the outbreak related strains. One predominant genotype was demon strated in 21/43 isolates of 11/27 patients. A cluster of this genotyp e was found in seven/eight patients on the cardiosurgical ICU. The epi demiologically unrelated strains all showed different genotypes as com pared to the predominant type. This survey proved RAPD-PCR to be a hig hly discriminatory and reproducible method for epidemiological studies of S. marcescens strains in nosocomial outbreaks.