Volume 10, Number 3—March 2004
Research
Legionella Infection Risk from Domestic Hot Water
Table 7
Differences in some water parameters according to Legionella species
| Characteristic | L. pneumophila serogroup 1 (n = 6) Mean ± SD | L. pneumophila serogroups 2–14 (n = 19) Mean ± SD | Legionella other species (n = 8) Mean ± SD | F score (p) |
|---|---|---|---|---|
| Sampling temperature (°C) |
29.4 ± 11.8 |
48.9 ± 4.4a |
31.2 ± 15.5 |
15.17 (<0.001) |
| Operating temperature (°C) |
43.3 ± 12.1a |
53.7 ± 5.9 |
57.0 ± 4.4 |
6.91 (<0.005) |
| Geometric mean |
Geometric mean |
Geometric mean |
||
| Free chlorine (μg/L) |
78.0 |
2.6a |
32.3 |
7.86 (<0.002) |
| Pseudomonas spp. (CFU/100 mL) | 0.4 | 19.1b | 0.6 | 3.31 (<0.05) |
ap < 0.05 versus the other two groups.
bp < 0.05 versus Legionella other species.


