Novel plasmid-borne multidrug resistance gene cluster including lsa(E) from a linezolid-resistant Enterococcus...

Area of Science:

• Microbiology
• Genomics
• Antimicrobial Resistance

Background:

• Porcine Enterococcus faecium is a reservoir for antibiotic resistance genes.
• Linezolid resistance in Enterococcus faecium is a growing public health concern.
• Plasmids play a crucial role in the dissemination of antimicrobial resistance.

Purpose of the Study:

• To characterize a novel plasmid from a linezolid-resistant porcine Enterococcus faecium isolate.
• To identify and analyze the multiresistance gene cluster harbored by this plasmid.
• To investigate the potential origin and evolution of the identified plasmid.

Main Methods:

• Complete genome sequencing of the 28,489 bp nonconjugative plasmid.
• Identification and annotation of resistance genes within the plasmid.
• Comparative genomic analysis to infer plasmid evolutionary history.

Main Results:

• A novel multiresistance gene cluster was identified, containing lnu(B), lsa(E), spw, aadE, aphA3, and two copies of erm(B).
• The identified genes confer resistance to macrolides, lincosamides, streptogramins, pleuromutilins, streptomycin, spectinomycin, and kanamycin/neomycin.
• Structural comparisons suggest the plasmid evolved through insertion element (IS)-mediated recombination.

Conclusions:

• The sequenced plasmid represents a significant vehicle for the spread of diverse antibiotic resistance mechanisms in porcine Enterococcus faecium.
• Understanding plasmid evolution is critical for combating antimicrobial resistance.
• This finding highlights the need for surveillance of antibiotic resistance in food-producing animals.