P. acnes susceptibility to antibiotics in each group
| Antibiotics, n (%) | Group 1 (n=93) | Group 2 (n=53) | Group 3 (n=81) | P value | ||
| Group 1a (n=67) | Group 1b (n=26) | Total (n=93) | ||||
| Azithromycin | 18 (26.9) | 8 (30.8) | 26 (28.0)*† | 27 (50.9) | 41 (50.6) | 0.003 |
| Clarithromycin | 17 (25.4) | 9 (34.6) | 26 (28.0)‡ | 30 (56.6) | 46 (56.8) | <0.001 |
| Clindamycin | 21 (31.3) | 7 (26.9) | 28 (30.1)*† | 29 (54.7) | 44 (54.3) | 0.001 |
| Erythromycin | 18 (26.9) | 7 (26.9) | 25 (26.9)*‡ | 27 (50.9) | 44 (54.3) | <0.001 |
| Doxycycline | 65 (97.0) | 25 (96.2) | 90 (96.8) | 53 (100) | 81 (100) | 0.067 |
| Tetracycline | 65 (97.0) | 24 (92.3) | 89 (95.7) | 52 (98.1) | 79 (97.5) | 0.664 |
Data were expressed as n (%).
*P<0.05 versus group 2.
†P<0.05 versus group 3.
‡P<0.001 versus group 3.