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Simultaneous outbreaks of infection due to Serratia marcescens in a general hospital
Abstract:
Seventy isolates of Serratia marcescens were obtained from 30 patients in different units of one hospital between April 1982 and February 1983. No common source was found. Not all isolates were multi-resistant and nearly all that were, fell into two main groups, A and B. These groups were defined by phage typing and cephalosporin sensitivity, all apart from one Group B isolate were multi-resistant, whereas Group A isolates contained multi-resistant and sensitive strains. Plasmid screening, resistance transfer studies and plasmid elimination experiments demonstrated that the multi-resistant phenotype was due to a 120 Mdal transmissible plasmid. Resistance to cephalosporins was chromosomally encoded.
Insights
This study investigated Serratia marcescens isolates from hospital patients, finding that multi-resistance often stemmed from a transmissible plasmid, while cephalosporin resistance was chromosomally encoded.
Area of Science:
- Microbiology
- Infectious Diseases
- Hospital Epidemiology
Background:
- Serratia marcescens is an opportunistic pathogen frequently isolated from hospital environments.
- Understanding the mechanisms of antimicrobial resistance in S. marcescens is crucial for infection control.
Purpose of the Study:
- To characterize the antimicrobial resistance patterns and genetic basis of multi-resistance in Serratia marcescens isolates from a hospital setting.
Main Methods:
- Isolates were obtained from patients over a 10-month period.
- Phage typing and cephalosporin sensitivity testing were performed.
- Plasmid analysis, including screening, transfer, and elimination studies, was conducted.
Main Results:
- Seventy S. marcescens isolates from 30 patients were analyzed, with no common source identified.
- Multi-resistant isolates predominantly belonged to two groups (A and B).
- A 120 Mdal transmissible plasmid was responsible for the multi-resistant phenotype, while cephalosporin resistance was chromosomally encoded.
Conclusions:
- The study identified a transmissible plasmid as the primary driver of multi-drug resistance in these Serratia marcescens isolates.
- Chromosomal mechanisms underlie cephalosporin resistance in this bacterial species.
- Findings highlight the importance of plasmid-mediated resistance in hospital-acquired infections.