Prevalence of Plasmid-mediated Quinolone Resistance (PMQR) Genes and Beta-lactamase Genes among Salmonella, Vibrio parahaemolyticus and Escherichia coli from Shellfish

Abstract

The objectives of the present study were to
investigate the prevalence of plasmid-mediated
quinolone-resistance (PMQR) genes and betalactamase
genes in Salmonella, Vibrio parahaemolyticus
and Escherichia coli from shellfish. A total of 35
Salmonella, 22 Vibrio parahaemolyticus, and 58 Escherichia
coli of shellfish origin were used in this study.
Antibiotic susceptibility testing of Salmonella, V.
parahaemolyticus, and E. coli against different antibiotics
was determined by disc diffusion method. The
minimum inhibitory concentrations (MIC) of nalidixic
acid and ciprofloxacin were analyzed by
microdilution method for all nalidixic acid/
ciprofloxacin-resistant strains. All the isolates were
screened for the presence of PMQR genes (qnrA,
qnrB, qnrS, qepA, aac(6’)-Ib-cr, and oqxA) and betalactamase
genes (blaTEM, blaSHV, and blaCTXM-1). The
prevalence of nalidixic acid resistance was 5.7, 9,
and 3.4% in Salmonella, V. parahaemolyticus and E.
coli, respectively. Approximately, 4.5% of V.
parahaemolyticus isolates were resistant to
ciprofloxacin. The prevalence of PMQR harboring
Salmonella, V. parahaemolyticus, and E. coli was 22, 9
and 3% respectively. The prevalence of betalactamase
genes in Salmonella, V. parahaemolyticus,
and E. coli were 17.14, 9 and 5.1%, respectively. The most prevalent PMQR and beta-lactamase genes were qnrS and blaTEM, respectively. The co-occurrence of PMQR and beta-lactamase genes in V. parahaemolyticus and Salmonella, from shellfish, poses a public health concern.