Table 2.
Antimicrobial susceptibility and point mutation in DNA topoisomerase of nontyphoid Salmonella strains isolated from food animals and humans carrying blaCTX-M genea
| Strain | DDT | Etest MIC (mg/liter)b |
Point mutation within QRDR of: |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AMP | CTX | CTX + CA | CAZ | CAZ + CA | FEP | ATM | FOX | NAL | CIP | gyrA | parC | ||
| 09-V06-15 | + | >256 | >16 | 0.064 | <0.5 | 0.125 | 16 | 24 | 1.5 | 256 | 0.125 | Asp87→Asn | Wild type |
| 09-V06-16 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 16 | 24 | 1.5 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-V06-20 | + | >256 | >16 | 0.094 | <0.5 | 0.25 | 24 | 24 | 2 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-V06-21 | + | >256 | >16 | 0.064 | <0.5 | 0.19 | 16 | 32 | 1.5 | 256 | 0.125 | Asp87→Asn | Wild type |
| 09-V06-22 | + | >256 | >16 | 0.094 | <0.5 | 0.25 | 16 | 24 | 2 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-V06-23 | + | >256 | >16 | 0.125 | <0.5 | 0.25 | 24 | 24 | 1.5 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-V06-25 | + | >256 | >16 | 0.125 | <0.5 | 0.25 | 16 | 24 | 2 | 512 | 0.25 | Asp87→Tyr | Wild type |
| 09-V06-28 | + | >256 | >16 | 0.064 | 24 | 0.125 | 12 | 16 | 1.5 | 128 | 0.125 | Asp87→Asn | Wild type |
| 09-V05-54 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 12 | 24 | 1.5 | 256 | 0.125 | Asp87→Asn | Wild type |
| 09-V05-56 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 16 | 24 | 1.5 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-V05-57 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 12 | 24 | 1.5 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-V05-58 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 16 | 24 | 1.5 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-V05-59 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 16 | 24 | 1.5 | 512 | 0.125 | Asp87→Asn | Wild type |
| 09-G-022 | + | >256 | >16 | 0.064 | <0.5 | 0.19 | 16 | 24 | 1.5 | 256 | 0.125 | Asp87→Asn | Wild type |
| 09-G-081 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 16 | 24 | 1.5 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-G-004 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 16 | 24 | 1.5 | 256 | 0.125 | Asp87→Asn | Wild type |
| 09-G-097 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 16 | 24 | 1.5 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-G-063 | + | >256 | >16 | 0.094 | <0.5 | 0.19 | 12 | 24 | 1.5 | 512 | 0.25 | Asp87→Asn | Wild type |
| 09-G-069 | + | >256 | >16 | 0.094 | 1.5 | 0.19 | 6 | 3 | 1.5 | 256 | 0.125 | Asp87→Gly | Wild type |
| 09-G-076 | + | >256 | >16 | 0.094 | 1.5 | 0.19 | 6 | 3 | 1.5 | 256 | 0.125 | Asp87→Gly | Wild type |
a
Abbreviations: DDT, double disk diffusion test; Etest, Epsilometer test; QRDR, quinolone resistance-determining region; AMP, ampicillin; CTX, cefotaxime; CAZ, ceftazidime; ATM, aztreonam; FEP, cefepime; FOX, cefoxitin; CA, clavulanic acid; NAL, nalidixic acid; CIP, ciprofloxacin.
b
MICs of ciprofloxacin and nalidixic acid were determined by agar dilution method following the CLSI guidelines.