Intracellular Survival of S. Typhi in Environmental Acanthamoeba

Dilip Abraham of Christian Medical College in India will analyze water samples from peri-urban and rural areas in India to study whether and how the typhoid fever-causing bacterium S. Typhi survives by living inside the common amoebae, Acanthamoeba. Acanthamoeba spp. are known to internalize S. Typhi, and may provide an intracellular environmental niche and extend survival of the bacteria. They will collect samples from drinking water sources and sewage lines in peri-urban and rural sites in Southern India. From these samples, they will recover Acanthamoeba and detect any internalized S. Typhi by culture and PCR. Whole genome sequencing will be used to conduct comparative genomic analysis of intracellular S. Typhi to identify any major virulence markers that promote its ability to be internalized by and remain viable within Acanthamoeba. This would help explain why persistence of S. Typhi in the environment can lead to sporadic outbreaks, and allow officials to plan preventative strategies beyond vaccines for the control and elimination of typhoid.