The worldwide distribution of genetically and phylogenetically diverse Bacillus cereus isolates harbouring Bacillus anthracis‐like plasmids

Abstract

Bacillus cereus is a close relative of B. anthracis, the causative agent of anthrax whose pathogenic determinants are located on pXO1 and pXO2 plasmids. Bacillus anthracis-like plasmids have been also noted among B. cereus, however, genetic features of B. cereus harbouring these elements remain largely undescribed, especially from the global perspective. Herein, we present the genetic polymorphism, population structure and phylogeny of B. cereus with pXO1-/pXO2-like plasmids originating from Argentina, Kazakhstan, Kenya and Poland. The plasmids were found in about 17% of the isolates, but their frequencies and expression of replicons differed within and between populations. In the multi-locus sequence typing, the bacteria exhibited high genetic polymorphism reflected by 116 sequencing types, including 84 singletons and 10 clonal complexes, which mainly consisted of isolates of the same origin. The phylogenetic analysis of pXO1-/pXO2-like positive B. cereus isolates revealed six independent clades; in certain clades individual populations predominated. Generally, B. cereus with pXO1-/pXO2-like plasmids did not indicate the genetic relationship with B. anthracis, and cannot be classified into an evolutionary independent anthrax line within the B. cereus group. Our report is of a crucial importance for discovering the genetic specificity and evolution of B. cereus bacilli.

Potential Enterotoxicity of Phylogenetically Diverse Bacillus cereus Sensu Lato Soil Isolates from Different Geographical Locations

“…Kenyan part of the collection was isolated during a previous study by Kaminska and co-workers [41], whereas the Polish isolates were isolated by Drewnowska and Swiecicka [22]. cytotoxicus NVH883-00 and B. cytotoxicus NVH391-98 were used as reference strains.…”

Assembly and Function of the Bacillus anthracis S-Layer

“…isolates, including B. cereus biovar anthracis CI and B. cereus G9241, have acquired pXO1-like plasmids and with them the ability to secrete anthrax toxins (54, 55, 57, 67, 149) (Figure 1). B. cereus G9241 and B. cereus biovar anthracis CI, along with B. anthracis , belong to clade 1 of B. cereus s.l.…”

Bacterial species – from theory to practice

“…HGT includes three different mechanisms: (a) transformation (obtaining DNA from the environment), (b) transduc-tion (when a bacteriophage is a vector that transmits DNA), and finally (c) conjugation (parasexual process, in which two bacteria of different types join altogether and a donor provides, while recipient receives genetic information). Especially the last one appears to be quite common among B. cereus and related bacilli, as showed by Clonal Frame statistical analyzes of homologues recombination to mutation ratio (Vos, Didelot, 2009;Kaminska et al, 2015).…”

“…First of them is linked to complex genetic structure of these bacteria. Initial studies using different molecular techniques for the genetic fingerprinting including RAPD (random amplification of polymorphic DNA) or PFGE (pulse-field gel electrophoresis) gave evidences on high level of genetic polymorphism, but they failed in case of establishing species-specific markers (Kaminska et al, 2015). A protein-depended approach called multi-locus enzyme electrophoresis (MLEE) also did not bring new insight into the taxonomy, however all these techniques rather suggested that we deal with one complex species (Helgason et al, 2000).…”