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Presence of mefA and mefE genes in Streptococcus agalactiae
1Laboratoire de Microbiologie, Université Victor Segalen Bordeaux 2, France. corinne.arpin@bacterio.u-bordeaux2.fr
Abstract:
Eighteen unrelated clinical isolates of Streptococcus agalactiae with the M phenotype harbored an mef gene. DNA sequencing showed that one of nine strains contained mefA (producing one amino acid substitution), whereas the remaining eight carried mefE (identity, 100%). Restriction analysis of PCR products indicated that the nine other strains also contained mefE.
Insights
Streptococcus agalactiae strains with the M phenotype commonly possess the mef gene. Most of these isolates contained mefE, with one strain harboring mefA, indicating genetic diversity in macrolide resistance.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a significant human pathogen.
- The M phenotype in GBS is associated with resistance to macrolide antibiotics.
- The mef gene is known to confer macrolide resistance in various bacteria.
Purpose of the Study:
- To investigate the genetic basis of the M phenotype in clinical isolates of Streptococcus agalactiae.
- To identify the specific mef gene variants present in these isolates.
- To understand the prevalence of different mef alleles in macrolide-resistant GBS.
Main Methods:
- Collection of 18 unrelated clinical isolates of Streptococcus agalactiae exhibiting the M phenotype.
- DNA sequencing to identify the specific mef gene variants.
- Polymerase Chain Reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis to confirm gene presence and type.
Main Results:
- All 18 clinical isolates of Streptococcus agalactiae with the M phenotype harbored a mef gene.
- DNA sequencing revealed that one isolate contained mefA, with a single amino acid substitution.
- The remaining eight sequenced isolates and the other nine isolates analyzed by restriction analysis carried the mefE gene with 100% identity.
Conclusions:
- The mefE gene is the predominant macrolide resistance gene associated with the M phenotype in this cohort of Streptococcus agalactiae clinical isolates.
- The presence of mefA in one isolate highlights genetic variability in macrolide resistance mechanisms within GBS.
- These findings are crucial for understanding and managing antibiotic resistance in Streptococcus agalactiae infections.