Genome Sequencing of S. Typhi in Protistan Reservoirs

Andrew Jackson of the University of Liverpool in the United Kingdom will determine whether the amoeba, Acanthamoeba, which is commonly found in water and soil, acts as a host for Salmonella Typhi bacteria, which cause typhoid fever, to support growth and disease spread in Malawi. Typhoid fever is a systemic, potentially fatal illness, usually contracted by consuming contaminated drinking water. An estimated 11-21 million cases occur worldwide each year. Acanthamoeba is known as the 'Trojan Horse' of the microbial world for its ability to host a number of human pathogens, including S. Typhi. It is speculated that Acanthamoeba acts as an environmental reservoir to facilitate the survival of S. Typhi, and perhaps other human pathogens. They will prove the widespread presence of Acanthamoeba-Salmonella associations directly by using single-cell DNA sequencing. Individual amoeba will be isolated from water and soil samples from typhoid hotspots in Malawi using fluorescence-activated cell sorting. Total DNA in each amoeba will be sequenced in order to identify carriage of S. Typhi strains. Single nucleotide polymorphism analysis will be used to compare these with bacteria in local clinical isolates to determine the role of Acanthamoeba in disease transmission.