Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4561748 | Food Research International | 2012 | 5 Pages |
Mutations in gyrase and topoisomerase genes (gyrA, gyrB, parC and parE) were examined among 30 multidrug-resistant (MDR) Salmonella isolates recovered from retail meats using PCR and DNA sequencing analysis. Six isolates had a single gyrA mutation (Ser83 → Phe or Ser83 → Tyr or Asp87 → Asn) with ciprofloxacin (Cip) minimum inhibitory concentrations (MICs) ranging from 0.125 to 0.5 μg/ml except 1 with 16 μg/ml. Three isolates had both a gyrA mutation (Ser83 → Tyr or Ser83 → Phe) and a parC mutation (Ser80 → Arg) (Cip MICs, 8 to 16 μg/ml). Fifteen isolates had both double mutations in gyrA (Ser83 → Phe and Asp87 → Gly or Asp87 → Asn) and a single mutation (Ser80 → Arg) in parC (Cip MICs, 8 to ≥ 16 μg/ml). Three had double gyrA mutations (Ser83 → Phe, Asp87 → Gly or Asp87 → Asn), one parC mutation (Ser80 → Arg), and 1 parE mutation (Lys428 → Gln or Gly442 → Ser) (Cip MICs, 8 to ≥ 16 μg/ml). One had double gyrA mutations (Ser83 → Phe, Asp87 → Gly or Asp87 → Asn), one parC mutation (Ser80 → Arg), and 2 parE mutations (Lys441 → Ile and Asp494 → Asn) (Cip MICs, 8 to ≥ 16 μg/ml). Isolates with single gyrA mutations were less resistant to quinolone and fluoroquinolones than those together with additional parC and/or parE mutations in Salmonella. Our findings confirmed the importance of point mutations in gyrase and topoisomerase in reduced susceptibility to quinolone and fluoroquinolones. Mutations in gyrA confer low-level quinolone and fluoroquinolone resistance, while additional gyrA mutation(s) together with parC and/or parE mutations increase the resistance to a high level.