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ABSTRACT Fungal contamination of drinking water distribution systems can impact water quality with implications for public health. We document an instance of Exophiala spp. biofilm contamination of customer taps in the Midwest United States following consumer complaints. Three samples of black biofilm were collected from customer taps in Ohio and then processed using next-generation DNA sequencing of the bacterial 16S and fungal ITS regions. Two samples with successful ITS sequencing were dominated by Exophiala spp., putatively identified as E. cancerae and E. lecanii-corni. Dominant bacterial phyla in samples included Proteobacteria, Bacteroidetes, Actinobacteria, and Acidobacteria. Bacterial composition varied substantially at the family and genus levels, and potentially pathogenic bacteria (i.e., Acinetobacter spp., Legionella spp., Mycobacterium spp., and Pseudomonas spp.) were detected. The potential for fungal contamination of drinking water distribution systems should be evaluated when biofilms are observed.
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Spatiotemporal trends in particle-associated microbial communities in a chlorinated drinking water distribution system
Various spatiotemporal, hydraulic, and water quality parameters can affect the microbial community composition of water within drinking water distribution systems (DWDSs). Although some relationships between various paravmeters and microbial growth are known, the effects of spatial and temporal trends on particle-associated microbial communities in chlorinated DWDSs remain poorly understood. The objectives of this study were to characterize the microbial community composition of both particle-associated bacteria (PAB) and total bacteria (TB) within a full-scale chlorinated DWDS, and assess relationships between microbiavvl community and various spatiotemporal, hydraulic, and water quality parameters. Bulk water samples were collected from the treatment plant, a storage tank, and 12 other sites in a rural chlorinated DWDS at varying distances from the treatment plant on four sampling dates spanning six months. Amplicon sequencing targeting the 16S rRNA gene was performed to characterize the microbial community. Gammaproteobacteria dominated the DWDS, and hydraulic parameters were well-correlated with differences in microbial communities between sites. Results indicate that hydraulic changes may have led to the detachment of biofilms and loose deposits, subsequently affecting the microbial community composition at each site. Spatial variations in microbial community were stronger than temporal variations, differing from similar studies and indicating that the highly varied hydraulic conditions within this system may intensify spatial variations. Genera containing pathogenic species were detected, withLegionellaandPseudomonasdetected at every site at least once andMycobacteriumdetected at most sites. However, only one sample had quantifiablePseudomonas aeruginosathrough quantitative polymerase chain reaction (qPCR), and no samples had quantifiableLegionella pneumophilaorMycobacterium avium, indicating a low human health risk. This study establishes spatial variations in PAB associated with varied hydraulic conditions as an important factor driving microbial community within a chlorinated DWDS.
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- Award ID(s):
- 2238953
- PAR ID:
- 10497215
- Editor(s):
- Kumar, Bimlesh
- Publisher / Repository:
- PLOS Water
- Date Published:
- Journal Name:
- PLOS Water
- Volume:
- 2
- Issue:
- 11
- ISSN:
- 2767-3219
- Page Range / eLocation ID:
- e0000183
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1371/journal.pwat.0000183
