| Genotype | Clinical isolates N (%) | Environmental isolates N (%) | ||||
| North | Center | South | North | Center | South | |
| VNI | 23 (24%) | 19 (28%) | 6 (86%) | 8 (50%) | 0 | 14 (100%) |
| VNII | 0 | 2 (3%) | 0 | 0 | 0 | 0 |
| VNIII | 7 (7%) | 14 (20%)a | 0 | 0 | 0 | 0 |
| VNIV | 65 (69%) | 33 (49%) | 1(14%) | 8 (50%) | 2 (100%) | 0 |
| Total | 95 | 68 | 7 | 16 | 2 | 14 |