TABLE 1.
Bactericidal activity of NCTa
| Strain | pH | Log10 reduction in CFU after incubation for:
|
|||||
|---|---|---|---|---|---|---|---|
| 1 h | 2 h | 3 h | 6 h | 9 h | 24 h | ||
| S. aureus ATCC 25923 | 7.0 | NDc | ND | 0.2 (0.5) | 1.9 (0.6) | 2.9 (1.0) | >4.5 (0.3) |
| 5.0 | 0.4 (0.6) | 1.4 (0.4) | 2.3 (0.4) | 3.9 (0.8) | ND | ND | |
| S. epidermidis ATCC 12228 | 7.0 | ND | ND | 0.1 (0.2) | 1.6 (0.3) | 3.0 (0.3) | >4.8 (0.1) |
| 5.0 | 0.9 (0.8) | 2.4 (0.6) | 4.0 (0.6) | >4.8 (0.1) | ND | ND | |
| P. mirabilis ATCC 14153 | 7.0 | ND | ND | 0.6 (0.6) | 2.9 (0.5) | >4.7 (0.1) | >4.7 (0.1) |
| 5.0 | 3.1 (0.4) | 4.5 (0.1) | >4.9 (0.1) | >4.9 (0.1) | ND | ND | |
| E. coli ATCC 11129 | 7.0 | ND | ND | 0.1 (0.3) | 1.1 (1.1) | 2.0 (1.7) | 3.2 (1.5) |
| 5.0 | 2.1 (0.3) | 4.1 (0.5) | >4.8 (0.2) | >4.8 (0.2) | ND | ND | |
| P. aeruginosa ATCC 27853b | 7.0 | ND | ND | 0.3 (0.6) | 0.4 (0.5) | 0.8 (0.6) | 1.7 (0.7) |
| 5.0 | 1.3 (0.6) | 3.3 (0.4) | >5.0 (0.2) | >5.0 (0.2) | ND | ND | |
a
Bactericidal activity of NCT (30 μM) against 0.2 × 106 to 1.0 × 106 CFU/ml during incubation in buffer solution at 37°C for different periods of time. Values are means (standard deviations) from four different experiments. In control experiments (without NCT), the maximum log10 reduction in CFU was 0.4, except that for S. epidermidis at pH 5.0 it was 0.9 after 3 h and 2.7 after 6 h.
b
For this organism, the mean log10 reduction in CFU after 72 h of incubation was 2.9 (standard deviation, 0.6).
c
ND, not determined.