TABLE 2.
Synergic effect of vancomycin and cerulenin in M. tuberculosis multidrug-resistant clinical isolates
| Isolatea | FPb | TN no.c | Resistance profiled |
Synergic effecte | MICf to vancomycin (μg/ml) | |
|---|---|---|---|---|---|---|
| First-line drugs | Second-line drugs | |||||
| 1 | OO1 | 16054 | INH, RIF, EMB, STR | RMC, PAS | + (0.30) | Between 50 and 75 |
| 2 | BE | 17182 | INH, RIF | ETH, PAS | ++ (0.10) (V5C0.5)f | Between 50 and 75 |
| 3 | W283 | 14178 | INH, RIF, EMB, PZA, STR | KAN, CAP, RFB, PAS | + (0.43) (V5C0.5)f | >200 |
| 4 | OO1 | 18048 | INH, RIF, PZA, STR | RFB, RMC, PAS | + (0.32) | >200 |
| 5 | P | 16442 | INH, RIF, PZA, STR | RMC, PAS | + (0.20) | Between 75 and 100 |
| 6 | P23 | 16906 | INH, RIF, EMB, PZA, STR | ETH, RMC, PAS | + (0.25) | 20 |
| 7 | BE | 18460 | INH, RIF, EMB, STR | ETH, CYC, CIP, KAN, CAP, RFB, RMC, PAS | +++ (0.05) | >200 |
| 8 | W | 2550 | INH, RIF, EMB, PZA, STR | ETH, OFX, KAN, CYC, PAS | + (0.28) | >200 |
| 9 | HD15 | 18985 | INH, RIF, EMB, PZA, STR | CYC, CIP, OFX, KAN, AMI, CAP, RFB, RMC, PAS | + (0.13) | 200 |
| 10 | W | 14614 | INH, RIF, EMB, STR | ETH, AMI, KAN, RFB, RIP | >0.5 | 200 |
| 11 | W12 | 15183 | INH, RIF, EMB, STR | ETH, AMI, KAN | >0.5 | >200 |
| 12 | W | 14003 | INH, RIF, EMB, STR | ETH, RFB, RMC, PAS | >0.5 | >200 |
| 13 | W148 | 13438 | INH, RIF, EMB, PZA, STR | KAN, AMI, RFB, RIP | >0.5 | >200 |
Isolates 7 to 9 are XDR strains.
FP, fingerprint name based on IS6110 typing and PHRI nomenclature.
TN no., tracking number, a PHRI unique identifier for each isolate.
Abbreviations: AMI, amikacin; CAP, capreomycin; CIP, ciprofloxacin; CYC, cycloserin; EMB, ethambutol; ETH, ethionamide; INH, isoniazid; KAN, kanamycin; OFX, ofloxacin; PAS, para-aminosalicylic acid; PZA, pyrazinamide; RFB, rifabutin; RIF, rifampin; RIP, rifapentine; RMC, rifamycin; STR, streptomycin.
Synergy between vancomycin (6 μg/ml) and cerulenin (1 μg/ml). Values in parentheses show Δx/Δy quotients. A Δx/Δy quotient of <0.5 in the case of a two-drug combination indicates a synergic effect of the drug action. The respective Δx/Δy quotients are illustrated as follows: +, <0.5; ++, <0.1; +++, <0.05.
These values were obtained from tests with 5 μg/ml vancomycin (V5) and 0.5 μg/ml cerulenin (C0.5). The BacT/Alert MP system was used to determine the MIC more accurately.