Table 1.
Comparison of antimicrobial susceptibility by Salmonella Typhi lineage.
| E test | Non-H58 (N=13) | H58 (N=65) | p value* | ||||
|---|---|---|---|---|---|---|---|
| MIC50 | MIC90 | GM (range) | MIC50 | MIC90 | GM (range) | ||
| Amoxicillin | 0.5 | 1 | 0.77 (0.38–38) | 0.75 | >256 | 1.43 (0.38–>256) | 0.0412 |
| Chloramphenicol | 3 | 4 | 2.7 (1.5–8) | 4 | 12 | 5.7 (2–>256) | 0.0147 |
| Ceftriaxone | 0.06 | 0.06 | 0.06 (0.05–0.13) | 0.09 | 0.19 | 0.11 (0.03–0.64) | 0.0004 |
| Gatifloxacin | 0.13 | 0.25 | 0.06 (0.01–2) | 0.13 | 2 | 0.21 (0.01–3) | 0.1197 |
| Nalidixic acid | >256 | >256 | 21.6 (1–>256) | >256 | >256 | 346.8 (1–>256) | 0.0004 |
| Ofloxacin | 0.25 | 0.75 | 0.24 (0.03–>32) | 0.5 | >3232 | 1.09 (0.03–>32) | 0.0240 |
| Trimethoprim sulphate | 0.02 | 0.05 | 0.03 (0.02–0.05) | 0.05 | 0.32 | 0.09 (0.01–>32) | 0.0016 |
| Ciprofloxacin | 0.13 | 0.75 | 0.11 (0.01–>32) | 0.38 | >32 | 0.80 (0.02–>32) | 0.0051 |
| Ciprofloxacin susceptibility group | 0.0008# | ||||||
| - Susceptible | 6 (46.2%) | 4 (6.2%) | |||||
| - Intermediate | 4 (30.8%) | 48 (73.8%) | |||||
| - Resistant | 3 (23.1%) | 13 (20.0%) | |||||
*Comparisons between Salmonella Typhi lineage for MICs and ciprofloxacin susceptibility groups were based on the Wilcoxon rank sum test and Fisher’s exact test. respectively.
MIC: minimum inhibitory concentration, measured in µg/ml.
#p value for comparison of susceptible vs. intermediate/resistant combined between groups by Fisher’s exact test is 0.001.
GM: geometric mean, the upper range of the values was determined by multiplying the MIC by 2 if the result was >X (for example, >256 = 256*2 = 512).