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Plasmid-borne AmpC beta-lactamases
Jan Walther-Rasmussen1, Niels Høiby
1Department of Clinical Microbiology, Rigshospitalet, National University Hospital, Copenhagen, Denmark. jawalras@mail.tele.dk
Abstract:
Historically, it was thought that ampC genes encoding class C beta-lactamases were located solely on the chromosome but, within the last 12 years, an increasing number of ampC genes have been found on plasmids. These have mostly been acquired by ampC-deficient pathogenic bacteria, which consequently are supplied with new and additional resistance phenotypes. This review discusses the phylogenetic origin of the plasmid-encoded AmpC beta-lactamases, their occurrence, and mode of spread, as well as their hydrolytic properties.
Insights
Plasmid-located ampC genes, encoding class C beta-lactamases, are increasingly found in pathogenic bacteria, conferring new resistance phenotypes. This review examines their origins, spread, and properties.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Historically, ampC genes were considered exclusively chromosomal.
- Recent findings show ampC genes are increasingly plasmid-borne.
- This shift impacts bacterial resistance profiles.
Purpose of the Study:
- To review the phylogenetic origins of plasmid-encoded AmpC beta-lactamases.
- To discuss their occurrence and mechanisms of spread.
- To analyze their hydrolytic properties.
Main Methods:
- Literature review of studies on ampC genes and beta-lactamases.
- Analysis of phylogenetic data.
- Examination of resistance phenotypes conferred by plasmid-borne ampC genes.
Main Results:
- Plasmid-mediated ampC genes have emerged as a significant factor in bacterial resistance.
- These genes are acquired by ampC-deficient bacteria, leading to new resistance phenotypes.
- The review covers the evolutionary history and dissemination pathways.
Conclusions:
- Plasmid-encoded AmpC beta-lactamases represent a growing challenge in antimicrobial resistance.
- Understanding their spread and properties is crucial for combating infections.
- Further research into their hydrolytic capabilities and evolutionary trajectory is warranted.