Table 4.
Cooling towers – comparison of action and alert levels using quantitative PCR (qPCR) and culture for Legionella pneumophila and Legionella spp
| Culture No. (%) | ||||
|---|---|---|---|---|
| Target | Action (>104 CFU l−1) | Alert (>103 CFU l−1) | Satisfactory (<103 CFU l−1) | |
| Leg. pneumophila | ||||
| qPCR No. (%) | Action (>5 × 104 GU l−1) | 7 (3)* | 2 (1) | 11 (5) |
| Alert (>5 × 103 GU l−1) | 9 (4) | 10 (4) | 9 (4) | |
| Satisfactory (<5 × 103 GU l−1) | 0 (0) | 25 (11) | 159 (69) | |
| Legionella spp. | ||||
| qPCR No. (%) | Action (>106 GU l−1) | 5 (2) | 9 (4) | 41 (18) |
| Alert (>105 GU l−1) | 11 (5) | 22 (9) | 44 (19) | |
| Satisfactory (<105 GU l−1) | 3 (1) | 8 (3) | 89 (38) | |
Figures in bold typeface represent those samples for which the results of both methods indicated the same action.
*
The number and (%) of tests displaying the indicated result.