Current Research
From Source to Tap: Linking the Drinking Water Microbiome to Human Health
Several studies have shown that drinking water harbors opportunistic pathogens, however, there is limited information about which abiotic and biotic factors regulate their abundance in “real” (not simulated) drinking water systems and whether clinically relevant species and strains are present. The overall aims of the study are to:
1. Determine how the abundance of common respiratory-tract opportunistic bacterial pathogens change from the drinking water distribution system to the point of use in households.
2. Identify physical and chemical parameters associated with the abundance of respiratory-tract opportunists and clinically relevant antibiotic resistance genes
3. Determine if specific strains recovered from persons with Cystic Fibrosis are also present in their drinking water.
To address these questions, I have developed several novel methods:
(a) a high-throughput, economical PacBio assay for Mycobacteria species and strain level identification.
(b) a high resolution LC-MS(Exactive Plus Orbitrap) method to monitor the concentration of the disinfection by-product N-Nitrosodimethylamine (NDMA).
Evaluating Microbial and Metal Levels in Water, Biofilms, and Corrosion Scales Before and After Service Line Replacement in Flint
In response to the water crisis in Flint, MI, a pilot project was initiated by the city to replace 30 lead service lines, which are the expected primary source of the lead in Flint’s drinking water. We sampled water from ten of those homes before service line replacement and 7 and 20 days after service line replacement. In addition to water samples, biofilms and corrosion scale mineralogy from samples obtained from replaced service lines were characterized to help determine conditions that favor the growth of opportunistic pathogens. The overall aim of this study was to monitor the effectiveness of the service line replacement program in terms of reducing levels of lead and to explore possible correlations between dissolved metal concentrations and levels of opportunistic bacterial pathogens.
Abundance of Opportunistic Bacterial Pathogens in a Potable Hot Water Pipe Loop System Before and After Implementation of Corrosion Control
The system under study is a domestic hot water pipe loop fed by municipal drinking water, which centrally heats and supplies water to University campus buildings. This system experiences widespread corrosion and scaling issues, resulting in frequent failures throughout the distribution system. The study aims to characterize the abundance of opportunistic bacterial pathogens such as Legionella and Mycobacterium before and after the introduction of a corrosion inhibitor.
PhD Research
The requirements for energy-efficient water treatment technologies are prompting renewed
interest in "biological" water treatment processes such as slow sand filtration.
These systems do not require chemicals or electricity to operate and can achieve a high
level of treatment mainly attributed to naturally occurring microorganisms within the
filter.
Several microbiologically mediated purification mechanisms have been hypothesised or
assumed to occur within biofilms that form in the filter but have never been
comprehensively verified.
My research aimed to determine the functional microbial ecology of slow sand filters (SSFs) by carrying
out both field sampling (at an industrial SSF site) and laboratory experimentation
(creation of lab-scale SSFs). In order to answer this complex question I
used a combination of traditional microbiological techniques alongside next-generation sequencing
(454 and Illumina) and DNA-SIP.
Other Research Interests
Previously I have worked on the phylogeny, virulence and serum-susceptibility of Yersinia ruckeri to Atlantic Salmon and Rainbow Trout. This work involved the development of an MLST scheme in order to determine the relationships between previously described subgroups. Additionally the virulence of different strains of Y.ruckeri were compared alongside serum-susceptibility between Rainbow trout and Atlantic salmon. This work was carried out as part of an industrial placement at CEFAS.
I have also worked on understanding the adherence mechanisms of Mannheimia haemolytica to ovine and bovine bronchial epithelial cells and organ cultures. Furthermore, I have worked on the biofilm forming potential of Pseudomonas aeruginosa on engineered surfaces.
