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Plasmid-borne macrolide resistance in Micrococcus luteus.
Wolfgang Liebl1, Wesley E Kloos2, Wolfgang Ludwig3
1Institut für Mikrobiologie und Genetik, Georg-August-Universität, Grisebachstr. 8, D-37077 Göttingen, Germany1.
Microbiology (Reading, England)
|August 15, 2002
Summary
A novel plasmid, pMEC2, conferring inducible erythromycin resistance was identified in human skin Micrococcus luteus. This finding highlights the potential role of non-pathogenic bacteria in spreading antibiotic resistance genes.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Antibiotic resistance is a growing global health concern.
- Plasmids are key vectors for the dissemination of antibiotic resistance genes.
- Micrococcus luteus, a common human skin commensal, is increasingly recognized for its role in carrying resistance determinants.
Purpose of the Study:
- To characterize a novel plasmid conferring macrolide and lincomycin resistance in Micrococcus luteus.
- To identify and locate the genetic determinant responsible for inducible erythromycin resistance.
- To investigate the potential role of Micrococcus luteus in the spread of antibiotic resistance.
Main Methods:
- Plasmid isolation and curing experiments in Micrococcus luteus.
- Heterologous expression in Corynebacterium glutamicum for gene localization.
- DNA sequencing and bioinformatic analysis of the resistance determinant.
- Inducibility assays with various macrolide antibiotics.
Main Results:
- A 4.2 kb plasmid, pMEC2, conferring resistance to erythromycin, other macrolides, and lincomycin was identified in Micrococcus luteus MAW843.
- Macrolide resistance was an inducible trait, triggered by subinhibitory concentrations of erythromycin and oleandomycin.
- The erythromycin-resistance determinant, erm(36), was localized to a 1.8 kb region of pMEC2 and identified as an ORF encoding a putative 23S rRNA adenine N(6)-methyltransferase.
- erm(36) showed significant similarity to resistance genes found in pathogenic corynebacteria.
Conclusions:
- This study reports the first plasmid-borne, inducible antibiotic resistance in micrococci.
- The erm(36) gene represents a novel macrolide resistance determinant.
- Saprophytic micrococci carrying antibiotic resistance genes may contribute to the dissemination of these determinants in the environment and to pathogens.