TABLE 2.
Activity of trovafloxacin against B. fragilis ATCC 23745 in pure culture or in mixed culture with either E. coli ATCC 25922 or VREF BM4147 determined by using the time-kill techniquea
| Inoculum (CFU/ml) | Culture | Emax (log10 CFU/ml ± SE) | EC50 (μg/ml ± SE) |
|---|---|---|---|
| 5 × 105 | B. fragilis | 2.0 ± 0.26 | 0.32 ± 1.50 |
| B. fragilis + E. coli | 3.0 ± 0.37 | 0.38 ± 1.35 | |
| B. fragilis + VREF | 3.0 ± 0.60 | 0.77 ± 1.48 | |
| 108 | B. fragilis | 3.6 ± 0.16 | 0.66 ± 1.20 |
| B. fragilis + E. coli | 4.0 ± 0.20 | 0.80 ± 1.18 | |
| B. fragilis + VREF | 4.0 ± 0.33 | 9.53 ± 1.27* | |
| 109 | B. fragilis | 3.2 ± 0.19 | 3.65 ± 1.19** |
| B. fragilis + E. coli | 0.5 ± 0.06 | ND | |
| B. fragilis + VREF | ND | ND |
a
Activities were determined after 6 h. ND, not determined, inadequate killing, or too few points to accurately calculate Emax and EC50. *, significantly different (P < 0.05) compared to the pure culture (108 CFU/ml), the mixed culture with E. coli (108 CFU/ml), and the mixed culture with VREF (5 × 105 CFU/ml). **, significantly different (P < 0.05) compared to other pure cultures.