Role of molecular typing in an outbreak of Salmonella paratyphi A.

D. S. Chandel, N. Nisar, K. L. Thong, T. Pang, R. Chaudhry

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Abstract

During the post monsoon season of 1996 an outbreak of human Salmonellosis caused by Salmonella serovar-paratyphi A occurred in New Delhi and had continued for over 2 months. A total of 36 clinically diagnosed enteric-fever cases were reported during this outbreak. The isolates were compared following their characterisation by biotyping, antibiogram-analysis, plasmid-profiling and IS200 probing, to study the relatedness in order to delineate a common source. The study included representative strains from both outbreak (15) and sporadic (7) cases for comparative analysis. Biotyping, antibiogram, whole cell protein-analysis and plasmid-profiling could not discriminate sporadic cases from outbreak strains, suggesting that a single clone/type (PT-1) may be prevalent in our region. In contrast, molecular-typing using IS200-probing revealed 2 clonally related strains circulating during the outbreak, as compared to the unrelated sporadic strains which exhibited considerable genetic diversity. Molecular analysis by IS200-probing, helped to assign an index case which provided a history of later outbreaks, since paratyphi A was repeatedly cultured in later outbreaks also. The study also suggests that genetic rearrangements can occur during the emergence of outbreaks. It reaffirmed the usefulness of IS200-probing in epidemiological investigations of Salmonella enterica serovars.

Original languageEnglish (US)
Pages (from-to)121-123
Number of pages3
JournalTropical gastroenterology : official journal of the Digestive Diseases Foundation
Volume21
Issue number3
Publication statusPublished - Jan 1 2000

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ASJC Scopus subject areas

  • Medicine(all)

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