Plasmid-mediated quinolone resistance among extended spectrum beta lactase producing Enterobacteriaceae from...

Area of Science:

• Microbiology
• Molecular Biology
• Antimicrobial Resistance

Background:

• Extended-spectrum beta-lactamase (ESBL)-producing Gram-negative bacteria pose a significant global health threat.
• Plasmid-mediated quinolone resistance (PMQR) genes contribute to reduced susceptibility to fluoroquinolones.
• Understanding the prevalence of PMQR genes in clinically relevant bacteria is crucial for effective treatment strategies.

Purpose of the Study:

• To determine the prevalence and molecular characteristics of PMQR genes in ESBL-producing Escherichia coli and Klebsiella spp. isolated from blood cultures in Hungary.
• To investigate the association between PMQR genes and resistance to specific quinolone antibiotics.
• To analyze trends in PMQR gene prevalence over an eight-year period.

Main Methods:

• Isolates of ESBL-producing E. coli and Klebsiella spp. from blood cultures were collected.
• Quinolone susceptibility testing was performed using the microdilution method.
• Polymerase chain reaction (PCR) was employed to detect the presence of specific PMQR genes (qnrA, qnrB, qnrC, qnrD, qnrS, aac(6')-Ib-cr, qepA, and oqxAB).

Main Results:

• A high frequency of PMQR genes was observed, with 75% (77/103) of ESBL-producing isolates harboring at least one PMQR gene.
• The most prevalent PMQR gene was aac(6')-Ib-cr (65%), followed by qnrS (6%).
• Genes qnrA, qnrB, qnrC, qnrD, and qepA were not detected. Increasing incidence of aac(6 ext{ extquoteright})-Ib-cr and oqxAB genes was noted over the past eight years.

Conclusions:

• PMQR genes are highly prevalent among ESBL-producing E. coli and Klebsiella spp. in Hungarian bloodstream infections.
• The aac(6 ext{ extquoteright})-Ib-cr gene is the dominant PMQR determinant in this population.
• The increasing prevalence of certain PMQR genes highlights the dynamic nature of antimicrobial resistance and necessitates ongoing surveillance.