Unravelling the Molecular Epidemiology and Genetic Diversity among Burkholderia pseudomallei Isolates from South India Using Multi-Locus Sequence Typing

PLoS One. 2016 Dec 19;11(12):e0168331. doi: 10.1371/journal.pone.0168331. eCollection 2016.

Abstract

There is a slow but steady rise in the case detection rates of melioidosis from various parts of the Indian sub-continent in the past two decades. However, the epidemiology of the disease in India and the surrounding South Asian countries remains far from well elucidated. Multi-locus sequence typing (MLST) is a useful epidemiological tool to study the genetic relatedness of bacterial isolates both with-in and across the countries. With this background, we studied the molecular epidemiology of 32 Burkholderia pseudomallei isolates (31 clinical and 1 soil isolate) obtained during 2006-2015 from various parts of south India using multi-locus sequencing typing and analysis. Of the 32 isolates included in the analysis, 30 (93.7%) had novel allelic profiles that were not reported previously. Sequence type (ST) 1368 (n = 15, 46.8%) with allelic profile (1, 4, 6, 4, 1, 1, 3) was the most common genotype observed. We did not observe a genotypic association of STs with geographical location, type of infection and year of isolation in the present study. Measure of genetic differentiation (FST) between Indian and the rest of world isolates was 0.14413. Occurrence of the same ST across three adjacent states of south India suggest the dispersion of B.pseudomallei across the south western coastal part of India with limited geographical clustering. However, majority of the STs reported from the present study remained as "outliers" on the eBURST "Population snapshot", suggesting the genetic diversity of Indian isolates from the Australasian and Southeast Asian isolates.

MeSH terms

  • Bacterial Typing Techniques / methods*
  • Burkholderia pseudomallei / classification
  • Burkholderia pseudomallei / genetics*
  • Burkholderia pseudomallei / isolation & purification
  • Cluster Analysis
  • DNA, Bacterial / analysis
  • Evolution, Molecular
  • Genetic Variation*
  • Humans
  • India / epidemiology
  • Melioidosis / epidemiology*
  • Melioidosis / microbiology
  • Molecular Epidemiology
  • Multilocus Sequence Typing / methods*
  • Sequence Analysis, DNA
  • Soil Microbiology

Substances

  • DNA, Bacterial

Grants and funding

The study was funded by Indian Council of Medical Research (2012-0465). Part of the work was also carried out at Defense Research and Development Organization India where experiment and data analysis was carried. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.