Volume 10, Number 3—March 2004
Research
Legionella Infection Risk from Domestic Hot Water
Table 4
Univariate analysis of system and building characteristics associated with microbial contaminationa
Characteristic | OR (95% CI) |
|||
---|---|---|---|---|
Legionella spp. yes/no (33/113) | Pseudomonas spp. yes/no (56/90) | Total count at 36°C high/low (62/84)b | Total count at 22°C high/low (35/111)b | |
Central heater |
9.24c (3.87 to 22.05) |
0.87 (0.40 to 1.85) |
0.92 (0.44 to 1.94) |
1.36 (0.59 to 3.12) |
Distribution site distance >10 m |
8.10c (3.41 to 19.23) |
0.47* (0.22 to 1.00) |
1.08 (0.54 to 2.17) |
1.51 (0.69 to 3.32) |
Tank capacity
>100 L |
5.21c (2.14 to 12.67) |
0.58 (0.24 to 1.43) |
0.58 (0.24 to 1.39) |
0.64 (0.22 to 1.83) |
Age of heating plant
>10 y |
3.24d (1.38 to 7.59) |
1.85e (0.94 to 3.64) |
1.14 (0.59 to 2.19) |
1.58 (0.73 to 3.43) |
House floor >3rd |
2.35e (1.04 to 5.30) |
1.38 (0.66 to 2.87) |
0.94 (0.45 to 1.96) |
1.24 (0.54 to 2.83) |
Apartments >12/building |
2.26e (0.99 to 5.18) |
1.48 (0.75 to 2.91) |
1.00 (0.52 to 1.94) |
1.13 (0.53 to 2.44) |
Sampling temperature >50°C |
0.62 (0.26 to 1.49) |
0.91 (0.24 to 3.40) |
1.16 (0.54 to 2.51) |
1.22 (0.54 to 2.75) |
Operating temperature >50°C | 0.69 (0.29 to 1.67) | 0.32d (0.15 to 0.70) | 1.74 (0.80 to 3.76) | 0.57 (0.24 to 1.36) |
aOR, odds ratio; CI, confidence interval.
bHigh >100 CFU/mL.
cp < 0.001.
dp < 0.01.
ep < 0.05.