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Published on: March 10, 2017
Stability of a blaGES-5-carrying plasmid in a Serratia marcescens nosocomial outbreak
Shoko Komatsu1, Ryohei Nomoto1, Noriko Nakanishi1
1Health Research Department 2, Kobe Institute of Health, Kobe, Japan.
Abstract:
In 2020, an outbreak of blaGES-5-carrying plasmid, p2020-O-9, harboring S. marcescens occurred in an intensive care unit in Kobe City, Japan [1]. During the outbreak, strains with and without p2020-O-9 were simultaneously isolated from three patients; hence, we evaluate the stability of p2020-O-9 and its contribution to carbapenem resistance. Growth and transcriptional expression of blaGES-5 were affected by the presence of p2020-O-9 at a meropenem concentration of at least 4 μg/mL. The blaGES-5-harboring plasmid could be transformed into Escherichia coli via electroporation, but not conjugation. The p2020-O-9 plasmid was highly unstable, and complete loss was observed at the 25th serial passage when antibiotic pressure was withdrawn. Therefore, the blaGES-5-harboring plasmid p2020-O-9 was unstable and non-conjugative, and contributed to meropenem resistance in a concentration-dependent manner in the previously reported S. marcescens nosocomial outbreak.
Insights
The blaGES-5 plasmid, p2020-O-9, carrying Serratia marcescens, was unstable and non-conjugative. It contributed to meropenem resistance in a concentration-dependent manner during a nosocomial outbreak.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- A 2020 outbreak of blaGES-5-carrying plasmid p2020-O-9 in *Serratia marcescens* occurred in a Japanese intensive care unit.
- Simultaneous isolation of strains with and without the plasmid from patients necessitated an evaluation of its stability and resistance contribution.
Purpose of the Study:
- To assess the stability of the p2020-O-9 plasmid.
- To determine the plasmid's contribution to carbapenem resistance.
- To investigate the transferability of the plasmid.
Main Methods:
- Plasmid stability assessed through serial passages with and without antibiotic pressure.
- Carbapenem resistance contribution evaluated by monitoring growth and blaGES-5 expression.
- Plasmid transferability tested via electroporation and conjugation into *Escherichia coli*.
Main Results:
- The p2020-O-9 plasmid was highly unstable, with complete loss by the 25th passage after antibiotic pressure removal.
- Plasmid presence affected bacterial growth and blaGES-5 transcriptional expression at meropenem concentrations ≥4 μg/mL.
- The plasmid was transferable to *Escherichia coli* via electroporation but not conjugation.
Conclusions:
- The blaGES-5-harboring plasmid p2020-O-9 is unstable and non-conjugative.
- p2020-O-9 contributes to meropenem resistance in a concentration-dependent manner.
- Findings are relevant to the *Serratia marcescens* nosocomial outbreak in Kobe City.
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