Sediment Biofilm Ecology in High-Typhoid-Incidence Rivers

Aaron Jenkins of the University of Sydney in Australia will combine genomics approaches with physical chemistry to identify the organisms and environmental factors in riverbeds that support the survival and spread of the bacterium, Salmonella enterica serovar Typhi, which causes typhoid. Aquatic environments are a major reservoir of typhoid, but how the bacteria survive in these conditions is unclear, making it difficult to prevent the disease spreading to humans. They hypothesize that S. Typhi survive in biofilms associated with sediments in riverbeds, and that the composition of this niche promotes its ability to infect humans. To test this, they will sample aquatic biofilms from areas of high, low, and zero typhoid incidence in Fiji, and identify the microbial communities supporting S. Typhi survival using antibody capture and metagenomics. They will also use fluorescence in situ hybridization to determine the spatial organization of S. Typhi in multispecies biofilms. In addition, they will analyze the composition of the sediments and soil of the riverbeds, and the nutrients being taken up by resident fish and crustaceans. By combining these results with their epidemiological data, they can identify the ecological niches that support high typhoid incidence, which will help develop and guide intervention strategies to block transmission to humans.