Work | Nathan L R Williams

Research

My research includes investigating microbial threats in coastal environments. This research is focused on endemic pathogens such as bacteria from the genus Vibrio, pathogens entering the environment via fecal contamination, as well as linking bacteria entering the environment via stormwater and antimicrobial resistance.

Microbial Source Tracking and Water Quality

Many recreationally used coastal environments are subject to fecal contamination. During this project we have combined both traditional fecal indicator bacteria (FIB) methods, molecular Microbial Source Tracking (MST) MST methods, and 16S rRNA gene amplicon sequencing data to precisely pinpoint animal/human sources and point sources of fecal contamination. We have tracked the relative abundances indicator species of 16S rRNA gene amplicon sequencing using the indiscpecies R package, as well as modeled the impact that drains have on the environment using the R package SourceTracker.

Vibrio Ecology

During this project, we have determined the patterns in abundance and diversity of the human and marine life pathogen bacteria, Vibrio. These patterns were studied along the Eastern Coastline of Australia, a latitudinal gradient that spans over 4000 km. Vibrio bacteria are known to thrive in warmer seawater temperatures. This is particularly relevant to Australia which has been pinpointed as a climate change hotspot, with sea surface temperatures set to rise dramitically in the coming years, generating the potential for much of Australia's coastline to become an ideal habitat for Vibrio bacteria.

Antimicrobial
Resistance

Antibiotic Resistance is a global health issue. In this project, we have linked MST fecal markers to genes that confer antimicrobial resistance. Additionally, using 16S rRNA sequencing, we have linked stormwater indicator bacteria to both MST fecal markers and genes conferring antimicrobial resistance. Of note, many of these indicator taxa were species which have strains that are known human pathogens.

Government Collaborations

During my Ph.D., I have contributed to multiple Microbial Source Tracking projects in collaboration with the Department of Primary Industries and Environment and Beachwatch.