Table 1.
Microorganism | Antimicrobial | No. of passages | No. of independent cultures passaged | MIC range (μg/ml) |
Passage at which resistance emerges in at least one culturea | |
---|---|---|---|---|---|---|
Initial | Final | |||||
E. coli ATCC 25922 | Ciprofloxacin | 25 | 2 | 0.0078 | 0.0039–1 | 11 |
NVC-422 | 25 | 2 | 1.5–4 | 1.5–4 | No resistance | |
P. aeruginosa PAO1 | Ciprofloxacin | 25 | 5 | 0.0625 | 1–2 | 3 |
NVC-422 | 25 | 5 | 6–12 | 6–12 | No resistance | |
S. aureus ATCC 29213 | Ciprofloxacin | 25 | 5 | 0.25–0.5 | 8 | 15 |
NVC-422 | 25 | 5 | 384–512 | 256–512 | No resistance | |
MRSA ATCC 33591 | Mupirocin | 50 | 7 | 0.25–0.5 | 4–16 | 9 |
Fusidic acid | 50 | 7 | 0.5 | 8–256 | 2 | |
Retapamulin | 50 | 7 | 0.0625–0.25 | 0.25–8 | 35 | |
NVC-422 | 50 | 7 | 96–768 | 96–512 | No resistance |
Resistance is defined as a sustained 4-fold increase in original MIC (4).