Linkage of vancomycin and high-level gentamicin resistance genes on the same plasmid in a clinical isolate of...

Area of Science:

• Microbiology
• Genetics
• Antimicrobial Resistance

Background:

• Enterococcus species are significant opportunistic pathogens.
• Antimicrobial resistance in Enterococcus is a growing public health concern.
• Co-occurrence of resistance genes on plasmids can accelerate the spread of multidrug resistance.

Purpose of the Study:

• To characterize a novel plasmid from a clinical isolate of Enterococcus faecalis.
• To investigate the genetic basis for combined vancomycin and high-level gentamicin resistance.
• To report the first instance of linked glycopeptide and high-level aminoglycoside resistance genes in Enterococcus.

Main Methods:

• Plasmid isolation and characterization from a clinical Enterococcus faecalis isolate.
• Hybridization assays using probes for vanB and aac(6")-aph(2") resistance genes.
• Molecular analysis to confirm gene linkage.

Main Results:

• A transferable 55-MDa plasmid was identified.
• The plasmid encoded resistance to vancomycin and high concentrations of gentamicin.
• The plasmid hybridized with vanB and aac(6")-aph(2") gene probes, indicating their linkage.

Conclusions:

• The identified plasmid represents a significant mechanism for the dissemination of multidrug resistance in Enterococcus.
• Linkage of vanB and aac(6")-aph(2") on a transferable plasmid highlights the potential for rapid evolution of highly resistant strains.
• This finding underscores the need for vigilant surveillance and effective infection control strategies against resistant Enterococcus infections.