Whole-genome sequencing and comparative analysis of heavy metals tolerant <i>Bacillus anthracis</i> FHq strain isolated from tannery effluents in Bangladesh

Abstract

Heavy metal contamination of the environment is a primary concern in Bangladesh. This study aims to characterize a novel heavy metal tolerant strain, Bacillus anthracis FHq, isolated from the tannery effluents of Savar, Bangladesh. The strain could tolerate up to 5 mM of lead nitrate, 2.5 mM of sodium arsenate, chromium chloride, cobalt chloride, 1.5 mM cadmium acetate, and 1 mM of sodium arsenite. Whole-genome sequencing analysis revealed that the genome of the strain is around 5.2 Mbp long, and the G + C content is 35.4%. Besides, FHq has genes cadC, zntA, arsCR, czcD, and chrA, which confer lead, arsenic, cobalt, and chromium resistance, respectively. A total of nineteen other closely related and completely sequenced B. anthracis strains were selected based on average nucleotide identity along with the FHq strain for phylogenomic and pan-genome analysis. The phylogenomic analysis predicted the inter-genomic evolutionary relationship of the strain isolated from Bangladesh, and it was closely related to a strain isolated from China. Pan-genome analysis revealed that the FHq strain possesses 6045 pan genes, 3802 core genes, and 152 unique genes in its genomic content. Hence, the genetic information and comparative analysis of the FHq strain might facilitate identifying the mechanisms conferring high resistance to lead in B. anthracis strains isolated from Bangladesh.