Table 4.
Determination of biofilm formation in CNS by genotypic and phenotypic methods
| Biofilm | CNS isolates | Total (n = 214) | ||||
|---|---|---|---|---|---|---|
| S. epidermidis | S. saprophyticus | S. haemolyticus | S. hominis | S. capitis | ||
| (n = 123) | (n = 40) | (n = 24) | (n = 15) | (n = 12) | ||
| Congo red agar (CRA) | ||||||
| Strong | 12 (9.8%) | 2 (5.0%) | 3 (12.5%) | 3 (20.0%) | - | 20 (9.3%) |
| Moderate | 12 (9.8%) | 2 (5.0%) | 5 (20.8%) | 2 (13.3%) | 2 (16.7%) | 23 (10.7%) |
| Weak/none | 99 (80.5%) | 36 (90.0%) | 16 (66.7%) | 10 (66.7%) | 10 (83.3%) | 171 (79.9%) |
| Tube adherence method (TM) | ||||||
| Strong | 33 (26.8%) | 4 (10.0%) | 2 (8.33%) | 3 (20.0%) | 2 (16.7%) | 44 (20.6%) |
| Moderate | 9 (7.3%) | 6 (15.0%) | 6 (25.0%) | 3 (20.0%) | - | 24 (11.2%) |
| Weak/none | 81 (65.9%) | 30 (75.0%) | 16 (66.7%) | 9 (60.0%) | 10 (83.3%) | 146 (68.2%) |
| Tissue culture plate (TCP) | ||||||
| Strong | 23 (18.7%) | 8 (20.0%) | 3 (12.5%) | 1 (6.7%) | - | 35 (16.4%) |
| Moderate | 32 (26.0%) | 9 (22.5%) | 4 (16.7%) | 7 (46.7%) | 3 (25.0%) | 55 (25.7%) |
| Weak/none | 68 (55.3%) | 23 (57.5%) | 17 (70.8%) | 7 (46.7%) | 9 (75.0%) | 124 (57.9%) |
| ica gene | ||||||
| Present | 29 (23.6%) | 5 (12.5%) | 2 (8.33%) | 3 (20.0%) | 2 (16.7%) | 41 (19.2%) |
| Absent | 94 (76.4%) | 35 (87.5%) | 22 (91.7%) | 12 (80.0%) | 10 (83.3%) | 173 (80.8%) |