TABLE 2.
Genotype and phenotype comparison of Salmonella spp. (n = 100)a
| Antimicrobial class | Antibiotic (no. of isolates tested) | No. of isolates |
Sensitivity (%) | Specificity (%) | |||
|---|---|---|---|---|---|---|---|
| Resistant phenotype |
Susceptible phenotype |
||||||
| Resistant genotype (TP) | Susceptible genotype (FN) | Resistant genotype (FP) | Susceptible genotype (TN) | ||||
| Beta-lactams | AM (100) | 75 | 1 | 0 | 24 | 98.7 | 100 |
| CTX-CRO (100) | 7 | 0 | 0 | 93 | 100 | 100 | |
| MEM (4) | 0 | 0 | 0 | 4 | —b | 100 | |
| Folate pathway inhibitors | SXT (100) | 21 | 2 | 0 | 77 | 91.3 | 100 |
| Macrolides | AZM (52) | 1 | 0 | 0 | 51 | 100 | 100 |
| Phenicols | CHL (48) | 10 | 2 | 2 | 34 | 83.3 | 94.4 |
| Quinolones | CIP (50) | 25 | 1 | 8 | 16 | 96.2 | 66.7 |
| Tetracyclines | T (48) | 29 | 0 | 0 | 19 | 100 | 100 |
| Total | 168 | 6 | 10 | 318 | 96.6 | 97.0 | |
a
TP, true positive; FN, false negative; FP, false positive; TN, true negative [sensitivity = TP/(TP + FN); specificity = TN/(TN +FP)]. AM, ampicillin; CTX-CRO, cefotaxime-ceftriaxone; MEM, meropenem; SXT, trimethoprim-sulfamethoxazole; AZM, azithromycin; CHL, chloramphenicol; CIP, ciprofloxacin; T, tetracycline.
b
Sensitivity and specificity were not computed because the resistant phenotype was constant.