Genotype Analysis of Bacillus anthracis Strains Circulating in Bangladesh

PLoS One. 2016 Apr 15;11(4):e0153548. doi: 10.1371/journal.pone.0153548. eCollection 2016.

Abstract

In Bangladesh, anthrax, caused by the bacterium Bacillus anthracis, is considered an endemic disease affecting ruminants with sporadic zoonotic occurrences in humans. Due to the lack of knowledge about risks from an incorrect removal of infected carcasses, the disease is not properly monitored, and because of the socio-economic conditions, the situation is under-reported and under-diagnosed. For sensitive species, anthrax represents a fatal outcome with sudden death and sometimes bleeding from natural orifices. The most common source of infection for ruminants is ingestion of spores during grazing in contaminated pastures or through grass and water contaminated with anthrax spores. Domestic cattle, sheep and goats can also become infected through contaminated bone meal (used as feed) originating from anthrax-infected carcasses. The present investigation was conducted to isolate B. anthracis organisms from 169 samples (73 soil, 1 tissue, 4 bone and 91 bone meal samples) collected from 12 different districts of Bangladesh. The sampling was carried out from 2012 to 2015. Twelve samples resulted positive for B. anthracis. Biomolecular analyses were conducted starting from the Canonical Single Nucleotide Polymorphism (CanSNP) to analyze the phylogenetic origin of strains. The analysis of genotype, obtained through the Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) with the analysis of 15 Variable Number Tandem Repeats (VNTR), demonstrated four different genotypes: two of them were previously identified in the district of Sirajganj. The sub-genotyping, conducted with Single Nucleotide Repeats analysis, revealed the presence of eight subgenotypes. The data of the present study concluded that there was no observed correlation between imported cattle feed and anthrax occurrence in Bangladesh and that the remarkable genetic variations of B. anthracis were found in the soil of numerous outbreaks in this country.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Anthrax / epidemiology
  • Anthrax / microbiology*
  • Anthrax / veterinary
  • Bacillus anthracis / genetics*
  • Bacillus anthracis / isolation & purification
  • Bacillus anthracis / metabolism
  • Bacterial Typing Techniques
  • Bangladesh / epidemiology
  • Bone and Bones / microbiology
  • Cattle / microbiology
  • Genotype
  • Goats / microbiology
  • Humans
  • Minisatellite Repeats
  • Polymorphism, Single Nucleotide
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sheep / microbiology
  • Soil Microbiology

Grants and funding

This study was funded by the Ministry of Health of Italy, Current Research 2013 “IZSPB 06/13” that supported the work of Istituto Zooprofilattico Sperimentale of Puglia and Basilicata. Work of FIR in Bangladesh was funded by the Bangladesh Academy of Sciences under BAS-USDA Program in Agricultural and Life Sciences. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.