Affiliation:
1. Kiwa Water Research, Nieuwegein, The Netherlands
Abstract
ABSTRACT
Representatives of the genus
Legionella
were detected by use of a real-time PCR method in all water samples collected directly after treatment from 16 surface water (SW) supplies prior to postdisinfection and from 81 groundwater (GW) supplies.
Legionella
concentrations ranged from 1.1 × 10
3
to 7.8 × 10
5
cells liter
−1
and were significantly higher in SW treated with multiple barriers at 4°C than in GW treated at 9 to 12°C with aeration and filtration but without chemical disinfection. No Legionellae (<50 CFU liter
−1
) were detected in treated water by the culture method.
Legionella
was also observed in untreated SW and in untreated aerobic and anaerobic GW. Filtration processes in SW and GW treatment had little effect or increased the
Legionella
concentration, but ozonation in SW treatment caused about 1-log-unit reduction. A phylogenetic analysis of 16S rRNA gene sequences of 202 clones, obtained from a selection of samples, showed a high similarity (>91%) with
Legionella
sequences in the GenBank database. A total of 40 (33%) of the 16S rRNA gene sequences obtained from treated water were identified as described
Legionella
species and types, including
L. bozemanii
,
L. worsleiensis
,
Legionella
-like amoebal pathogen types,
L. quateirensis
,
L. waltersii
, and
L. pneumophila
. 16S rRNA gene sequences with a similarity of below 97% from described species were positioned all over the phylogenetic tree of
Legionella
. Hence, a large diversity of yet-uncultured Legionellae are common members of the microbial communities in SW and GW treated at water temperatures of below 15°C.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
100 articles.
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