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Transferable vancomycin and teicoplanin resistance in Enterococcus faecium
R Leclercq1, E Derlot, M Weber
1Service de Bactériologie-Virologie-Hygiène, Hôpital Henri Mondor, Université Paris XII, Créil, France.
Abstract:
Enterococcus faecium BM4165 and BM4178, isolated from immunocompromised patients, one treated with vancomycin, were inducibly resistant to high levels of the glycopeptide antibiotics vancomycin and teicoplanin but susceptible to the new lipopeptide daptomycin (LY146032). Strain BM4165 was also resistant to macrolidelincosamide-streptogramin B-type (MLS) antibiotics. The genes conferring resistance to glycopeptides and to MLS antibiotics in strain BM4165 were carried on plasmids pIP819 and pIP821, respectively; pIP819 also carried genes that encoded resistance to MLS antibiotics. The two plasmids, which were distinct although related, were self-transferable to other E. faecium strains. Plasmid pIP819 could also conjugate to E. faecalis, Streptococcus sanguis, S. pyogenes, S. lactis, and Listeria monocytogenes, in which it conferred inducible glycopeptide resistance, but not to S. aureus. Glycopeptide-inactivating activity was not detected, and the biochemical mechanism of resistance remains unknown. Based on this first report of transferable resistance to glycopeptides, we anticipate dissemination of resistance to these antibiotics in gram-positive cocci and bacilli in which it can be phenotypically expressed.
Insights
This study reports transferable glycopeptide resistance in Enterococcus faecium BM4165, a strain also resistant to MLS antibiotics. This transferable resistance raises concerns about the spread of antibiotic resistance in gram-positive bacteria.
Area of Science:
- Microbiology
- Antibiotic Resistance Research
- Molecular Biology
Background:
- Enterococcus faecium strains BM4165 and BM4178 exhibit resistance to vancomycin and teicoplanin.
- These strains were isolated from immunocompromised patients, with one patient having received vancomycin treatment.
- Strain BM4165 also displays resistance to macrolide-lincosamide-streptogramin B (MLS) antibiotics.
Purpose of the Study:
- To investigate the genetic basis of antibiotic resistance in Enterococcus faecium strains BM4165 and BM4178.
- To determine the transferability of glycopeptide and MLS resistance genes between bacterial strains.
- To assess the potential for dissemination of glycopeptide resistance among gram-positive bacteria.
Main Methods:
- Isolation and characterization of Enterococcus faecium strains BM4165 and BM4178.
- Plasmid analysis to identify genes responsible for glycopeptide and MLS resistance.
- Conjugation experiments to assess the self-transferability of resistance plasmids to various bacterial species.
Main Results:
- Genes conferring resistance to glycopeptides and MLS antibiotics in strain BM4165 are located on plasmids pIP819 and pIP821.
- Plasmid pIP819, carrying both glycopeptide and MLS resistance genes, is self-transferable to E. faecium and other gram-positive species, including Listeria monocytogenes.
- Inducible glycopeptide resistance was conferred to E. faecium, Streptococcus species, and Listeria monocytogenes, but not to Staphylococcus aureus.
Conclusions:
- This study presents the first report of transferable glycopeptide resistance in Enterococcus faecium.
- The findings indicate a significant risk for the dissemination of glycopeptide resistance among gram-positive cocci and bacilli.
- The biochemical mechanism of glycopeptide resistance remains to be elucidated.