Table 2.
Characteristics of the 52 Salmonella enterica serovar Typhi isolates belonging to Groups A, B and C, India 2004–2011.
| Group | No. of isolates | NAL MIC (μg/ml) |
CIP MIC (μg/ml) |
QRDR mutation | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| MIC50 | MIC90 | GM | MIC range | MIC50 | MIC90 | GM | MIC range | |||
| A | 16 | 2 | 3 | 2.06 | 1.5–3 | 0.012 | 0.016 | 0.012 | 0.006–0.023 | No mutation |
| B | 34a | 6 | 8 | 6.44 | 3–12 | 0.125 | 0.19 | 0.13 | 0.064–0.5 |
gyrB 464 Ser→Tyr (n = 2) Ser→Phe (n = 31) Ser→Thre (n = 1) |
| C | 2 | 16 | 16 | 16 | 16 | 0.25 | 0.38 | 0.38 | 0.25–0.38 |
gyrA 83 Ser→Tyro |
NAL, nalidixic acid; CIP, ciprofloxacin; GM, geometric mean; QRDR, quinolone resistance-determining region of the gyrA, gyrB, parC and parE genes.
a
13 isolates were additionally resistant to chloramphenicol, co-trimoxazole and ampicillin.