Text

theses

ETD graduate

Household plumbing biofilms can harbor and transmit bacterial pathogens. Pulmonary infections by nontuberculous mycobacteria (NTM) can occur from this transmission route. NTM infections are increasing around the world and in New Jersey (NJ). To understand the abundance of NTM in NJ private wells today, a field study was performed (Ch. II). To evaluate how NTM abundance may change in water environments in the future, a critical literature review was performed (Ch. III). For the field study, plumbing biofilm samples were collected from sinks and showerheads in homes using private wells (N=19) and in homes of NTM patients (N=5). DNA extracts were analyzed by qPCR to quantify mycobacterial marker genes and by amplicon sequencing to describe the microbiomes where NTM were observed. Water samples were analyzed for basic water quality parameters and fecal indicator organisms. Participants completed surveys about their wells and home water systems to enable testing of potential relationships between these environmental factors and the microbial communities. NTM were observed in more than half of private well biofilm samples using qPCR and in all of the selected samples analyzed by amplicon sequencing (N=29/70), even when below detection by qPCR. Samples from patient homes, most of whom used public water supply, had similar abundances of NTM as samples from private wells. Physiography and within-home location (e.g., kitchen sink) explained some variation in concentrations of mycobacteria genes. One microbial family with no known human pathogens, Rikenellaceae, was identified as a potential antagonist to mycobacteria using linear discriminant analysis effect size (LEfSe). This study illuminated the widespread nature of NTM in private well water systems without disinfection selection pressures, and worked towards understanding ecological interactions that may aid or slow the growth of NTM toward ecological engineering of healthy plumbing microbiomes.

The critical literature review was performed systematically by searching specific terms in several online databases. Connections were made between NTM fate and transport, climate change, engineering decisions, and societal changes, and uncertainties highlighted. Environmental conditions discussed with respect to NTM risk included changing temperature, humidity, salinity, rainfall, and extreme weather events. NTM risk was then considered under climate/societal scenarios described by Intergovernmental Panel on Climate Change (IPCC) scientists. Findings indicate that the resilience of NTM under a variety of environmental conditions (e.g., warm temperatures, eutrophication) may increase their net prevalence in water environments under climate change, increasing exposure. Water management decisions may also influence exposure to NTM as water scarcity requires increased reliance on reclaimed water. Water managers may control risk of exposure through innovative water treatment processes and equitable water management decisions, turning towards an integrated One Water approach to reduce and/or mitigate the impacts of de facto reuse.

ETD_11625

M.S.

Includes bibliographical references

doi:10.7282/t3-e47z-tq79

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