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Occurrence of Legionella in Nonpotable Reclaimed Water
Author(s) -
Johnson William J.,
Jjemba Patrick K.,
Bukhari Zia,
LeChevallier Mark W.
Publication year - 2018
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.5942/jawwa.2018.110.0021
Subject(s) - legionella , microbiology and biotechnology , serotype , legionella pneumophila , biology , reclaimed water , mesophile , polymerase chain reaction , veterinary medicine , bacteria , ecology , medicine , biochemistry , genetics , reuse , gene
Legionella was monitored in reclaimed water systems and were detected by culture in 50% of 115 samples, while 80% of the samples were positive by quantitative polymerase chain reaction (qPCR). The lowest level of Legionella was in a system that practiced biological nutrient removal and maintained an average 0.3 mg/L free chlorine residual. The difference between qPCR and ethidium monoazide treated samples was used as an indicator of viability, and the greatest difference was in a chloraminated system, where the molecular method indicated a 9% viability. Ninety‐six percent of the species were L. pneumophila , and 87% were identified as L. pneumophila serotype 1. Total amoebae (summed as cysts or trophozoites) were detected in 100% of samples from all six systems, and were mostly (50–95%) in the active trophozoite phase. In the chloraminated system, 87% of the mesophilic amoebae and 66% of the thermophilic amoebae were in the cyst phase.