| Tests | Penicillin resistant (n = 375) | Penicillin sensitive (n = 29) | ||
| Negative, Number (%) | Positive, Number (%) | Positive, Number (%) | Negative, Number (%) | |
| Chromogenic | 4 (1.1%) | 371 (98.9%) | 2 (6.9%) | 27 (93.1%) |
| Iodometric | 6 (1.6%) | 369 (98.4%) | 1 (3.4%) | 28 (96.6%) |
| Acidimetric | 10 (2.71%) | 365 (97.3%) | 3 (10.3%) | 26 (89.7%) |