Currently, our knowledge of fungal ecology in engineered drinking water systems is
limited, despite the potential for these systems to serve as a reservoir for opportunistic
pathogens. In this study, hot water samples were collected both prior to and following the
addition of monochloramine as an on-site disinfectant in a hospital hot water system.
Fungal ecology was then analyzed by high throughput sequencing of the fungal ITS1 region.
The results demonstrate that the genera Penicillium, Aspergillus, Peniophora, Cladosporium
and Rhodosporidium comprised the core fungal biome of the hospital hot water system.
Penicillium dominated the fungal community with an average relative abundance of 88.89%
(±6.37%). ITS1 sequences of fungal genera containing potential pathogens such as Aspergillus,
Candida, and Fusarium were also detected in this study. No significant change in
fungal community structure was observed before and after the initiation of on-site monochloramine
water treatment. This work represents the first report of the effects of on-site
secondary water disinfection on fungal ecology in premise plumbing system, and demonstrates
the necessity of considering opportunistic fungal pathogens during the evaluation
of secondary premise plumbing disinfection systems.