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Epidemiological survey of an outbreak of multiresistant Serratia marcescens by PCR-fingerprinting
S B Debast1, W J Melchers, A Voss
1Dept. of Medical Microbiology, University Hospital St. Radboud, Nijmegen, The Netherlands.
Abstract:
During an outbreak of Serratia marcescens from May to November 1993 43 strains obtained from 27 ICU patients infected or colonized with multiresistant S. marcescens were genotypically characterized with random amplified polymerase chain reaction (RAPD-PCR)-fingerprinting. In addition, 43 epidemiologically unrelated control isolates were selected. PCR-fingerprinting identified ten different genotypes of S. marcescens among the outbreak related strains. One predominant genotype was demonstrated in 21/43 isolates of 11/27 patients. A cluster of this genotype was found in seven/eight patients on the cardiosurgical ICU. The epidemiologically unrelated strains all showed different genotypes as compared to the predominant type. This survey proved RAPD-PCR to be a highly discriminatory and reproducible method for epidemiological studies of S. marcescens strains in nosocomial outbreaks.
Insights
This study used random amplified polymerase chain reaction (RAPD-PCR) fingerprinting to analyze multiresistant Serratia marcescens strains during a 1993 ICU outbreak. RAPD-PCR effectively identified distinct genotypes, revealing a predominant strain linked to patient clusters.
Area of Science:
- Microbiology
- Infectious Diseases
- Molecular Epidemiology
Background:
- Nosocomial outbreaks of multiresistant bacteria pose significant threats to patient safety in intensive care units (ICUs).
- Serratia marcescens is an opportunistic pathogen frequently implicated in healthcare-associated infections, particularly in vulnerable patient populations.
- Accurate genotypic characterization is crucial for understanding transmission dynamics and controlling the spread of resistant strains during outbreaks.
Purpose of the Study:
- To genotypically characterize multiresistant Serratia marcescens strains isolated from ICU patients during an outbreak.
- To evaluate the discriminatory power and reproducibility of random amplified polymerase chain reaction (RAPD)-PCR fingerprinting for epidemiological surveillance of S. marcescens.
Main Methods:
- Genomic DNA was extracted from 43 S. marcescens isolates obtained from 27 infected or colonized ICU patients.
- Random amplified polymerase chain reaction (RAPD)-PCR fingerprinting was performed to generate genetic profiles for each isolate.
- Epidemiologically unrelated control strains were also analyzed using RAPD-PCR for comparison.
Main Results:
- RAPD-PCR identified ten distinct genotypes among the outbreak-related S. marcescens strains.
- A predominant genotype was identified in 21 out of 43 isolates from 11 out of 27 patients, with a notable cluster in the cardiosurgical ICU.
- Epidemiologically unrelated strains exhibited different genotypes compared to the predominant outbreak type, highlighting strain specificity.
Conclusions:
- Random amplified polymerase chain reaction (RAPD)-PCR is a highly discriminatory and reproducible molecular technique for investigating nosocomial outbreaks of Serratia marcescens.
- The findings underscore the utility of molecular typing in tracing the source and spread of multidrug-resistant pathogens within healthcare settings.
- Effective implementation of genotypic analysis aids in targeted infection control strategies to mitigate the impact of bacterial outbreaks.