Molecular Typing of Serratia marcescens by RAPD, ERIC-PCR and REP-PCR

Shin, Kyeong Seob

Abstract

BACKGROUND
This study was carried out in order to find an efficient and reliable method for genotyping Serratia marcescens, which frequently causes a nosocomial infection, by PCR-based methods. METHODS: The DNA fingerprinting by RAPD, ERIC and REP-PCR was performed for 24 isolates of S. marcescens obtained from 24 patients hospitalized at Chungbuk National University Hospital from March to May 2001. Reproducibility of the methods and minimum inhibitory concentration (MIC) of antibiotics against the isolates were also determined. RESULTS: The patients bearing epidemic S. marcescens were catheterized in their urinary tracts and admitted to the ICU or neurosurgical ward. All of the epidemic isolates showed the same susceptibility pattern. The epidemic isolates demonstrated resistance to all the test antibiotics except imipenem. The non-epidemic isolates showed variable susceptibility with a low MIC, except for one isolate. The DNA fingerprints by RAPD, ERIC and REP-PCR demonstrated an identical band pattern in epidemic strains but demonstrated different band patterns in non-epidemic strains. The PCR-based methods were found to be easy to manipulate, rapid in reaching conclusions, powerful in discrimination, and reproducible in results. CONCLUSIONS: RAPD, ERIC-PCR and REP-PCR are proved to be a reliable and efficient method for genotyping the epidemic S. marcescens in the laboratory.