Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

The Vi capsular polysaccharide (ViPS) protects Salmonella enterica subspecies enterica serotype Typhi (S.Typhi) in vivo by multiple mechanisms. Recent microbiological reports from typhoid endemic countries suggest that acapsulate S.Typhi may occur in nature and contribute to clinical typhoid fever that is indistinguishable from disease caused by capsulate strains. The prevalence and genetic basis of ViPS-negative S.Typhi isolates in children from Kathmandu, Nepal, were tested in 68 isolates. Although 5.9% of isolates tested negative for capsular expression by slide agglutination tests, a novel multiplex PCR assay and individual PCR analyses demonstrated the presence of all 14 genes responsible for the synthesis, transportation and regulation of the ViPS. These data suggest that phenotypically acapsulate S.Typhi may not have a genetic basis for the same.

Original publication




Journal article


J Trop Pediatr

Publication Date





317 - 320


Kathmandu, Nepal, Vi, acapsulate, polysaccharide, salmonella, typhi, typhoid, Child, Genes, Bacterial, Genome, Bacterial, Humans, Infant, Mutation, Nepal, Phenotype, Polymerase Chain Reaction, Polysaccharides, Bacterial, Prevalence, Salmonella typhi, Typhoid Fever