Table 3. Antimicrobial susceptibility of E. faecalis isolates from chickens obtained from Southeast Asian countries.
| Antimicrobial | Break point (mg/l) |
MIC range (mg/l) |
MIC50 (mg/l) |
MIC90 (mg/l) |
% of antimicrobial resistance |
|||
|---|---|---|---|---|---|---|---|---|
| Vietnam (n=22) |
Indonesia (n=58) |
Thailand (n=37) |
Total (n=117) |
|||||
| Ampicillin | 16a) | <0.125–8 | 1 | 2 | 0 | 0 | 0 | 0 |
| Kanamycin | 64b) | 32–>512 | 64 | >512 | 77.3c), d) | 29.3 | 27 | 37.6 |
| Gentamicin | 512b) | 4–>512 | 16 | 512 | 40.9c), d) | 6.9 | 0 | 11.1 |
| Dihydrostreptomycin | 256a) | 16–512 | 128 | >512 | 95.4c), d) | 41.4 | 40.5 | 51.3 |
| Erythromycin | 8a) | <0.125–>512 | >512 | >512 | 90.9d) | 77.6e) | 48.6 | 70.9 |
| Lincomycin | 128a) | 32–>512 | >512 | >512 | 90.9d) | 79.3e) | 54.1 | 73.5 |
| Oxytetracycline | 16a) | 1–512 | 256 | >512 | 100c), d) | 65.5 | 56.8 | 69.2 |
| Vancomycin | 32a) | 0.5–8 | 2 | 4 | 0 | 0 | 0 | 0 |
| Chloramphenicol | 32a) | 4–128 | 16 | 128 | 86.3c), d) | 8.6 | 21.6 | 27.4 |
| Enrofloxacin | 16b) | 0.25–128 | 1 | 64 | 36.4d) | 19 | 5.4 | 17.9 |
MIC: Minimal inhibitory concentration. a) The value was the CLSI break point, b) The value was the JVARM breakpoint [13], c)–e) Superscripts indicate significantly higher percentage of antimicrobial resistance in Vietnam than in Indonesia (c), Vietnam than in Thailand (d), Indonesia than in Thailand (e) (P<0.05).