Impact of S. Typhi Genome Structure Upon Survival in Water

Gemma Langridge of Quadram Institute Bioscience in the United Kingdom, along with co-investigators Aaron Jenkins of the University of Sydney in Australia and France Daigle of the University of Montreal in Canada, will collect different isolates of S. Typhi, which causes typhoid fever, to analyze genomic structure, growth, and gene expression to better understand how it can survive at low levels in water, and determine how it can be reactivated for monitoring. Typhoid fever is a potentially fatal disease associated with exposure to contaminated water. S. Typhi, the bacteria causing the disease, exist in water in a so-called viable-but-non-culturable (VBNC) state, which makes it difficult to monitor for control efforts. Their previous analyses have shown that the VBNC bacteria undergo structural rearrangements of their genomes and changes in gene expression, which may explain the reduced growth. They will analyze the correlation between genome structure and growth of different S. Typhi isolates using samples isolated from around 25 typhoid fever cases, and a further 75 stored isolates across the endemic region. Of these, a selection will be tested for their ability to enter a VBNC state and survive in water from areas of high and low typhoid incidence. One isolate that has entered VBNC with a defined structural genotype will be tested to establish the conditions most suitable for resuscitation.