TABLE 3.
Legionella and free-living amoebae in the biofilm on plasticized polyvinyl chloride
| Column no. | L. pneumophila serogroup or ST (strain) | Temp (°C) |
Legionella concn |
V. vermiformis concn at day 112 (cell eq/cm2)c | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Biofilm (CFU/cm2) |
Water (CFU/ml) |
Biofilm/water ratio |
No. of CFU/pg of ATP (avg ± SD)b | |||||||
| 50th percentile | 90th percentile | 50th percentile | 90th percentile | 50th percentile | 90th percentile | |||||
| 1 | L. pneumophila non-SG1 | 38 | 1.2 × 107 | 1.7 × 107 | 290 | 8.9 × 103 | 1.3 × 105 | 2.1 × 105 | 431 ± 177 (433) | 380 |
| 2 | ST62 (LP8) | 38 | 9.8 × 106 | 1.7 × 107 | 720 | 6.4 × 103 | 6.9 × 104 | 1.1 × 105 | 454 ± 150 (405) | 1,390 |
| 3 | ST62 (LP8) | 38–42 | NAa | NA | NA | NA | NA | NA | NA | 6 |
| 4 | ST1 (LP25) | 38 | 7.7 × 106 | 1.2 × 107 | 370 | 1.5 × 103 | 1.2 × 104 | 3.9 × 104 | 305 ± 95 (261) | 190 |
| 5 | ST1 (LP25) | 38–42 | NA | NA | NA | NA | NA | NA | NA | 13 |
| 6 | ST62 (LP3) | 38 | 5.0 × 106 | 8.1 × 106 | 240 | 1.7 × 103 | 3.0 × 104 | 5.8 × 104 | 263 ± 60 (253) | 240 |
| 7 | ST62 (LP3) | 38–42 | NA | NA | NA | NA | NA | NA | NA | 6 |
| 8 | ST47 (LP7) | 38 | 8.6 × 106 | 1.4 × 107 | 740 | 2.1 × 103 | 1.3 × 104 | 2.7 × 104 | 302 ± 199 (322) | 450 |
| 9 | ST47 (LP7) | 38–42 | NA | NA | NA | NA | NA | NA | NA | <3 |
a
NA, not applicable/not analyzed.
b
Values in parentheses represent the 50th percentile.
c
V. vermiformis concentrations, expressed as cell equivalents (eq), at 38°C differ significantly (P < 0.05) from those in the columns operated at 42°C. Concentrations are means of duplicate qPCR tests in single samples with a relative standard deviation of 13 to 32%. Acanthamoeba spp. were not detected (<5 cell eq cm−2).