Table 3.
Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of A11 against 16 drug-resistant Salmonella enterica strains. All strains were grown in Tryptic Soy Agar (TSA).
| Serovar | Strains | Drug susceptibility* | MIC(MBC) in µg/ml | ||
|---|---|---|---|---|---|
| Resistance | Intermediate | A11 | Nisin | ||
| S. Typhimurium | ATCC 13311 | – | – | 15.63 (31.25) | 16,000 |
| S. Typhimurium | H1-001 | Amp, Ctx, C, Cp, NA, S, T | Amc | 62.5 (125) | > 16,000 |
| S. Typhimurium | H1-006 | NA | S, Cp | 125 (125) | > 16,000 |
| S. Typhimurium | H1-011 | Amp, S, T | Amc, Ctx, Cp, NA | 62.5 (62.5) | > 16,000 |
| S. Typhimurium | H1-015 | Amp, S | Cp | 62.5 (62.5) | > 16,000 |
| 4,5,12:i:- | H1-024 | Amc, Amp, Ctx, C, NA, S, SxT | Cp | 62.5 (62.5) | > 16,000 |
| S. Typhimurium | H1-041 | Amp, Ctx, C, S, T, SxT | Amc, Cp, NA | 125 (125) | > 16,000 |
| S. Typhimurium | H1-062 | Amc, Amp, Ctx, C, NA, S, T | Cp | 125 (125) | > 16,000 |
| 4,5,12:i:- | H1-100 | Amp, C, Cp, S, T, SxT | Amc, NA | 62.5 (62.5) | > 16,000 |
| 4,5,12:i:- | H2-010 | Amp, C, S, T | – | 62.5 (62.5) | > 16,000 |
| 4,5,12:i:- | H2-039 | Amp, S, T | – | 62.5 (125) | > 16,000 |
| 4,5,12:i:- | H2-042 | Amp, C, S, T, SxT | Cp | 62.5 (125) | > 16,000 |
| 4,5,12:i:- | H2-047 | Amp, S | Cp | 62.5 (125) | > 16,000 |
| 4,5,12:i:- | H2-049 | Amp, S, T | – | 62.5 (125) | > 16,000 |
| 4,5,12:i:- | H2-067 | Amp, S, T | – | 62.5 (62.5) | > 16,000 |
| 4,5,12:i:- | H2-071 | Amp, Ctx, C, S, T, SxT | Cp | 125 (125) | > 16,000 |
| 4,5,12:i:- | H2-089 | Amp, S | – | 62.5 (125) | > 16,000 |
Amc amoxicillin/clavulinic acid, Amp ampicillin, Ctx cefotaxime, C chloramphenicol, Cp ciprofloxacin, NA nalidixic acid, Nor norfloxacin, S streptomycin, T tetracycline, SxT sulfamethoxazole/trimethoprim.
*In vitro drug susceptibility of all isolates was performed using Kirby-Bauer disk diffusion test, in accordance with the standard procedure recommended by the Clinical and Laboratory Standards Institute (CLSI), and interpreted as susceptible, resistant, or intermediate according to interpretative criteria based on CLSI breakpoints29. The data were taken from Huoy, Pornruangwong, Pulsrikarn, and Chaturongakul (2014).