Detection of aac(6')-Ib-cr in avian pathogenic Escherichia coli isolates in Japan

Area of Science:

• Veterinary Microbiology
• Antimicrobial Resistance
• Molecular Epidemiology

Background:

• Avian pathogenic Escherichia coli (APEC) poses a significant threat to poultry health and food safety.
• Plasmid-mediated quinolone resistance (PMQR) genes are a growing concern in bacterial pathogens.
• Understanding the prevalence of PMQR in APEC is crucial for monitoring and controlling antimicrobial resistance.

Purpose of the Study:

• To determine the prevalence of specific PMQR genes in APEC strains isolated in Japan.
• To identify the genetic characteristics of APEC isolates carrying PMQR genes.

Main Methods:

• Polymerase chain reaction (PCR) was used to detect nine PMQR genes (qnrA, qnrB, qnrC, qnrD, qnrS, aac(6 ime)-Ib-cr, qepA, and oqxAB).
• Phylogenetic grouping, multi-locus sequence typing (MLST), and serotyping were performed on positive isolates.

Main Results:

• None of the 117 APEC strains tested positive for qnrA, qnrB, qnrC, qnrD, qnrS, qepA, or oqxAB.
• One APEC isolate was identified as a producer of the aac(6 ime)-Ib-cr gene.
• The AAC(6 ime)-Ib-cr positive isolate belonged to phylogenetic group A, sequence type 167, and an untypable serogroup.

Conclusions:

• The study reports the first detection of the aac(6 ime)-Ib-cr gene in bacteria from food-producing animals in Japan.
• The limited prevalence of PMQR genes suggests specific resistance patterns in Japanese APEC strains.
• Further surveillance is needed to track the emergence and spread of antimicrobial resistance genes in APEC.