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Plasmid-borne high-level resistance to gentamicin in Enterococcus hirae, Enterococcus avium, and Enterococcus
M Straut1, G de Cespédès, T Horaud
1Laboratoire des Staphylocoques et des Streptocoques, Institut Pasteur, Paris, France.
Antimicrobial Agents and Chemotherapy
|May 1, 1996
Summary
This study identified gentamicin resistance plasmids in Enterococcus species from Romania, Tunisia, and Portugal. These plasmids utilized Tn4001-like elements and, in one case, also carried tetracycline resistance genes.
Area of Science:
- Microbiology
- Molecular Biology
- Antimicrobial Resistance
Background:
- Enterococcus species are important in clinical settings.
- Plasmid-mediated antibiotic resistance is a growing concern.
- Gentamicin resistance is frequently observed in Enterococcus.
Purpose of the Study:
- To characterize plasmids encoding high-level gentamicin resistance (Gmr) in Enterococcus species.
- To investigate the genetic elements responsible for Gmr.
- To identify additional resistance determinants on these plasmids.
Main Methods:
- Plasmid isolation and characterization.
- Identification of resistance genes and mobile genetic elements.
- Conjugation experiments (implied).
Main Results:
- Plasmids pICC8, pIP1700, and pIP1701 from Enterococcus hirae, E. avium, and E. raffinosus harbored Gmr.
- Gmr was associated with Tn4001-like elements or truncated versions.
- pICC8 also contained chloramphenicol, erythromycin, and tetracycline-minocycline (TetM) resistance.
- The tetM gene on pICC8 was located on a Tn916-like element.
Conclusions:
- Plasmids play a significant role in the dissemination of gentamicin resistance in Enterococcus species.
- Tn4001-like elements are key mediators of Gmr.
- Co-selection of multiple resistance genes, including TetM, on the same plasmid is possible.