Abstract/Summary

The built environment has often been referred to as a microbial wasteland, that is heavily shaped by the microbiota of human occupants, building design and environmental factors. While persistence of microorganisms in the built environment is typically attributed to frequent deposition of microorganisms from external sources, there is evidence to suggest that within the built environment there are areas of endogenous growth and microbial proliferation. Handwashing sinks and traps are environments that favour microbial colonisation and proliferation and are increasingly identified as reservoirs of antibiotic-resistant pathogens in clinical environments. Despite the importance of sinks and their traps in clinical outbreaks, there are still large gaps in our knowledge regarding the composition and diversity of sink microbial communities, particularly in non-clinical communal areas. This thesis focuses on characterising the microbial communities and their dynamics in P-traps present in communal restrooms to better understand the potential implications of interactions between human occupants and these environments, and to determine their importance as reservoirs. Firstly, the bacterial and fungal sink trap communities were characterised from a variety of university buildings, identifying the core microbial community, and demonstrating the influence of humans and their activities on sink community composition. Secondly, sink trap bacterial community diversity and composition was investigated temporally, followed by an intervention event with sodium hypochlorite to explore stability. Results showed communities becoming more stable over time, converging to similar compositions across all individual sinks and that the effects of sodium hypochlorite were short-lived. This suggests that the environment selects and those that colonise will persist. Finally, an alternative restroom P-trap microbial community was investigated, those of urinals. This study showed considerable variability in community composition and structure across individual urinals, however similar bacterial taxa were observed, notably the high prevalence and abundance of the genus Dolosicoccus was observed. Collectively this thesis provides insight into trap microbial communities emphasising the importance of traps as reservoirs of active microorganisms and provides evidence that sink trap communities are stable and resilient to perturbations in non-clinical environments. Furthermore, highlights the application of combining different sequencing techniques to identify novel species.