Table 3.
Occurrence (the number of positives/no. samples) and counts (GC, MPN or CFU/100 mL) of studied microbes in water, biofilm and contamination site samples in outbreak II.
| Microbe | Water before Chlorination | Water after Chlorination | Water after Intensive Chlorination | Biofilms | Contamination Site |
|---|---|---|---|---|---|
| Sapovirus | 0/1 | 1/2 (<LOQ 2) | 0/3 | 0/1 | 1/1 (1.9 × 105) |
| Norovirus GI | 0/1 | 0/2 | Nd | 0/1 | 1/1 (2.3 × 105) |
| Norovirus GII | 0/1 | 0/2 | Nd | 0/1 | 1/1 (2.8 × 103) |
| Adenovirus | 0/1 | 0/1 | Nd | Nd | 0/1 |
| ETEC, EPEC, EHEC and EAEC 3 | 0/1 | 1/2 (EPEC) | 0/3 | 0/1 | 1/1 (EHEC, ETEC, EAEC) |
| Campylobacter spp. | 0/1 | 0/2 | Nd | Nd | 0/1 |
| Giardia spp. and Cryptosporidium spp. | 0/1 | 0/2 | 0/3 | 0/1 | 0/1 |
| GenBac3 (rDNA) | 1/1 (5.9 × 103) | 1/2 (6.6 × 103) | 3/3 (<LOQ) | 1/1 (3.1 × 102) | 1/1 (6.3 × 1010) |
| GenBac3 (rRNA) | 1/1 (4.4 × 105) | 1/2 (1.9 × 105) | 3/3 (<LOQ) | 1/1 (1.7 × 104) | 1/1 (1.1 × 1013) |
| HF183 (rDNA) | 1/1 (7.7 × 102) | 1/2 (9.0 × 102) | 0/3 | 0/1 | 1/1 (6.1 × 109) |
| HF183 (rRNA) | 1/1 (5.1 × 103) | 1/2 (3.8 × 102) | 0/3 | 0/1 | 1/1 (8.0 × 1012) |
| E. coli | 1/5 (2.0 × 100) | 0/19 | 0/48 | 0/1 | 1/1 (5.5 × 105) |
| Coliform bacteria | 1/5 (1.2 × 101) | 1/19 (3.0 × 100) | 0/48 | 0/1 | 1/1 (1.7 × 106) |
| Intestinal enterococci | 2/5 (1.0 – 2.0 × 100) | 2/19 (1.0–2.0 × 100) | 2/48 (4.0 × 10−1 – 1.0 × 100) | 0/1 | 1/1 (9.0 × 104) |
| C. perfringens | Nd 1 | 1/9 (1.0 × 10−1) | 0/22 | 0/1 | 1/1 (5.9 × 103) |
1 Nd, not done; 2 LOQ, limit of quantitation; 3 Qualitative analysis.