Phylogenetic diversity of Orientia tsutsugamushi isolates in patients with scrub typhus in Bengaluru, India

Indian J Med Microbiol. 2019 Jul-Sep;37(3):438-441. doi: 10.4103/ijmm.IJMM_19_267.

Abstract

Scrub typhus has re-emerged as an important cause of acute febrile illness in India. There is a dearth of information on strain diversity of Orientia tsutsugamushi from Karnataka, India, hence the present study sought to address this issue. One hundred clinically suspected cases of scrub typhus/rickettsiosis (as per the DHR-ICMR guidelines) were included. Nested-polymerase chain reaction (PCR) for 56-kDa gene and phylogenetic analysis was performed. PCR was positive in 22 cases and phylogenetic analysis showed the presence of different strains, with predominance of clustering (57%) with Gilliam-type for the first time in Karnataka. Knowledge of genetic diversity has implications in development of diagnostics and vaccine.

Keywords: Orientia tsutsugamushi; phylogenetic analysis; polymerase chain reaction; scrub typhus.

MeSH terms

  • DNA, Bacterial / genetics
  • Genotype
  • Humans
  • India
  • Orientia tsutsugamushi / classification
  • Orientia tsutsugamushi / genetics*
  • Phylogeny
  • Polymerase Chain Reaction
  • Scrub Typhus / classification
  • Scrub Typhus / genetics
  • Sequence Analysis, DNA

Substances

  • DNA, Bacterial