TABLE 3.

Quantitative PCR of the 430-bp PCR product from the experimental and commercial SSF

Sample	Legionella DNA concn (ng g−1 or ng liter−1)	Estimated % of Legionella DNA in total DNA extracted	No. of cells estimated by real-time PCR (cells g−1 or cells liter−1)
			Mean	SD
Reservoir	0.013	0.003	3.1 × 103	7.8 × 102
IFWa	0.097	0.02	2.3 × 104	1.3 × 104
IFWa	0.145	0.03	3.4 × 104	1.4 × 104
IFWa	0.318	0.07	7.4 × 104	1.3 × 104
Top layer	0.99	0.20	2.3 × 105	7.7 × 104
T1b	17.068	0.34	3.9 × 106	2.2 × 106
T2b	9.212	0.18	2.1 × 106	6.6 × 105
T3b	2.634	0.05	6.1 × 105	2.1 × 105
Middle layer	0.268	0.05	6.2 × 104	2.2 × 104
Bottom layer	0.062	0.01	1.5 × 104	1.0 × 104
Recirculating water	19.98	0.1	4.7 × 106	2.5 × 106
OFWc	0.187	0.04	4.4 × 104	1.1 × 104
OFWc	0.235	0.05	5.5 × 104	1.1 × 104
SSF-2	0.635	0.051	1.7 × 105	3.7 × 104
SSF-3	0.326	0.0004	3.4 × 105	5.4 × 104
SSF-3 (5 cm down)	0.566	0.006	6.8 × 105	2.7 × 105
SSF-3 (10 cm down)	0.119	0.00014	3.1 × 104	1.4 × 104
SSF-3 (15 cm down)	0.078	0.00009	6.0 × 104	1.6 × 104
SSF-3 (20 cm down)	0.260	0.0003	5.5 × 104	3.0 × 104
SSF-4	0.207	0.0003	1.3 × 105	1.6 × 104
SSF-5	0.728	0.018	3.8 × 105	1.4 × 105
SSF-6a	0.904	0.023	5.5 × 105	8.1 × 104
SSF-6b	1.227	0.031	4.5 × 105	2.3 × 105
SSF-7a	0.454	0.011	2.5 × 105	5.1 × 104
SSF-7b	1.408	0.035	6.9 × 105	7.1 × 105

^aIFW, inflow water. The results obtained for three replicate samples taken during the study are shown.

^bA sand bed sample was taken in the first 1 cm of the top layer sample in three replicate columns.

^cOFW, outflow water. The results obtained for two replicate samples taken during the study are shown.