Table 1.
RV-PCR and culture method results for CDF-buffer samples seeded with B. atrophaeus spores and exposed to various concentrations of chlorine.
| Free chlorine concentration (mg/L) | RV-PCR method |
Culture method |
Results agree? | |
|---|---|---|---|---|
| Delta Ct | Present/Absent | Membrane filtration (cfu/mL) | ||
| 4.60 | 4.36 | Absent | 1 | No |
| 3.80 | 10.41 | Present | <0.05 | No |
| 3.76 | −0.36 | Absent | <0.05 | Yes |
| 2.33 | −0.50 | Absent | <0.05 | Yes |
| 1.79 | 10.82 | Present | 0.05 | Yes |
| 1.73 | 6.47 | Absent | 1 | No |
| 1.72 | 3.57 | Absent | 1 | No |
| 1.54 | 11.87 | Present | 7 | Yes |
| 1.16 | 7.11 | Absent | 85 | No |
| 1.14 | 23.01 | Present | 840 | Yes |
| 0.75 | 17.06 | Present | 7300 | Yes |
| 0.59 | 17.34 | Present | 4600 | Yes |
| 0.04 | 13.58 | Present | 4800 | Yes |
| 0.00 | 11.94 | Present | 8500 | Yes |
| 0.00 | 15.41 | Present | 12,000 | Yes |
Acronyms: mg/L, milligrams per liter; Ct, cycle threshold; cfu/mL, colony forming units per milliliter; <, less than.