TABLE 2.
Comparison between agar dilution-based phenotypic resistance and antimicrobial resistance mechanism according to AMR genetic determinants for 141 C. coli isolates
| Antimicrobial | Phenotypic profile | No. (%) of isolates | AMR determinant(s) detected | No. with AMR gene present/absent | Correlation ratea (%) | Sensitivityb (%) | Specificityc (%) | PPVd (%) | NPVe (%) |
|---|---|---|---|---|---|---|---|---|---|
| Ciprofloxacin and nalidixic acid | Resistant | 138 (97.87) | gyrA T86I | 137/1 | 99.29 | 99.28 | 100 | 100 | 75.00 |
| Susceptible | 3 (2.13) | 0/3 | |||||||
| Gentamicin | Resistant | 80 (56.74) | aph(3′)-III and/or aac(6′)-aph(2′') and/or ant(6)-Ia | 77/3 | 89.36 | 96.25 | 80.33 | 86.52 | 94.23 |
| Susceptible | 61 (43.26) | 12/49 | |||||||
| Streptomycin | Resistant | 99 (70.21) | aph(3′)-III and/or aac(6′)-aph(2′') and/or ant(6)-Ia | 83/16 | 84.40 | 83.84 | 85.71 | 93.26 | 69.23 |
| Susceptible | 42 (29.79) | 6/36 | |||||||
| Tetracycline | Resistant | 137 (97.16) | tet(O) | 115/22 | 84.40 | 83.94 | 100 | 100 | 16.67 |
| Susceptible | 4 (2.84) | 0/4 | |||||||
| Erythromycin | Resistant | 83 (58.87) | 23S rRNA A2075G and/or erm(B) | 79/4 | 96.45 | 95.18 | 98.28 | 98.75 | 93.44 |
| Susceptible | 58 (42.13) | 1/57 | |||||||
| Azithromycin | Resistant | 85 (60.28) | 23S rRNA A2075G and/or erm(B) | 79/6 | 95.04 | 92.94 | 98.21 | 98.75 | 90.16 |
| Susceptible | 56 (39.72) | 1/55 | |||||||
| Totalf | Resistant | 760 (77.00) | 707/53 | 92.60 | 93.03 | 91.19 | 97.25 | 79.62 | |
| Susceptible | 227 (23.00) | 20/207 |
Calculated as the sum of true positives and true negatives divided by all tested isolates.
Calculated by dividing true positives by the sum of true positives and false positives.
Calculated by dividing true negatives by the sum of true negatives and false negatives.
Calculated by dividing true positives by the sum of true positives and false negatives.
Calculated by dividing true negatives by the sum of true negatives and false positives.
For gentamicin and streptomycin, aph(3′)-III and/or aac(6′)-aph(2′') and/or ant(6)-Ia was used for calculation. For erythromycin and azithromycin, 23S rRNA A2075G and/or erm(B) was used for calculation.