Evolutionary processes and environmental factors underlying the genetic diversity and lifestyles of Bacillus cereus group bacteria

Patiño-Navarrete, Rafael; Sanchis, Vincent

doi:10.1016/j.resmic.2016.07.002

Cited by 43 publications

(32 citation statements)

References 90 publications

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“…It must be noted that the existing literature suggests a high degree of genetic diversity between the various species examined here, and questions related to the taxonomy of B. anthracis, B. cereus, and B. thuringiensis continue to be argued among researchers in this field [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Additional insight into these taxonomic questions will no doubt be provided by comparative genomics, as well as by molecular discrimination analyses using prominent biomarkers such as the chaperonin protein (GroEL) and the topoisomerase (gyrB) [50].…”

Section: Discussionmentioning

confidence: 90%

Phylogenetic Analysis of Bacillus cereus sensu lato Isolates from Commercial Bee Pollen Using tRNACys-PCR

et al. 2020

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Endospore-forming bacteria related to the Bacillus cereus group produce toxins that cause illnesses in organisms from invertebrates to mammals, including foodborne illnesses in humans. As commercial bee pollen can be contaminated with these bacteria, a comprehensive microbiological risk assessment of commercial bee pollen must be incorporated into the relevant regulatory requirements, including those that apply in Mexico. To facilitate detection of members of this group of bacteria, we have developed a PCR strategy that is based on the amplification of the single-copy tRNACys gene and specific genes associated with tRNACys to detect Bacillus cereus sensu lato (B. cereus s.l.). This tRNACys-PCR-based approach was used to examine commercial bee pollen for endospore-forming bacteria. Our analysis revealed that 3% of the endospore-forming colonies isolated from a commercial source of bee pollen were related to B. cereus s.l., and this result was corroborated by phylogenetic analysis, bacterial identification via MALDI-TOF MS, and detection of enterotoxin genes encoding the HBL and NHE complexes. The results show that the isolated colonies are closely related phylogenetically to B. cereus, B. thuringiensis, and B. bombysepticus. Our results indicate that the tRNACys-PCR, combined with other molecular tools, will be a useful approach for identifying B. cereus s.l. and will assist in controlling the spread of potential pathogens.

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Section: Discussionmentioning

confidence: 90%

Phylogenetic Analysis of Bacillus cereus sensu lato Isolates from Commercial Bee Pollen Using tRNACys-PCR

et al. 2020

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“…Because RBP reporter binding is dependent on the presence of the cognate receptors (Sap or GamR, respectively) on the bacterial host cell surface, recognition is not dependent on the presence or absence of B. anthracis virulence plasmids (pXO1 and pXO2). Thus, B. cereus strains harboring such plasmids [ 1 ] cannot per se be expected to be labeled by the RBP reporters. Conversely, the rather weak binding of RBP reporters to cells of rare B. anthracis C-branch strain A1074 may be linked to the overall poor growth of this strain in our hands on both solidified and liquid media.…”

Section: Discussionmentioning

confidence: 99%

“…Bacillus anthracis causing the zoonotic infectious disease anthrax in mammals and humans phylogenetically belongs to the Bacillus cereus sensu lato group of very closely related Firmicutes bacteria. The group comprises several familiar species, including Bacillus cereus sensu stricto , Bacillus thuringiensis , Bacillus weihenstephanensis , Bacillus mycoides and a variety of lesser characterized members [ 1 ]. Classical, culture-based techniques and classification upon phenotypic traits such as susceptibility against penicillin or lack of hemolysis are ambiguous and often fail to reliably differentiate B. anthracis from its close relatives.…”

Section: Introductionmentioning

confidence: 99%

“…group. In fact, most species of this group should be regarded as a single species [ 1 ]. However, some species carry characteristic virulence plasmids on which the genetic information for certain toxins is encoded.…”

Section: Introductionmentioning

confidence: 99%

“…These phenotypic characteristics facilitate clinical differentiation, but do not always constitute reliable criteria for rapid identification of individual species. For example, virulence plasmids typical for B. anthracis (pXO1 and pXO2) can also be found in certain B. cereus isolates [ 1 ].…”

Section: Introductionmentioning

confidence: 99%

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Rapid Microscopic Detection of Bacillus anthracis by Fluorescent Receptor Binding Proteins of Bacteriophages

Braun¹,

Wolfschläger²,

Reetz³

et al. 2020

Microorganisms

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Bacillus anthracis, the etiological agent of anthrax disease, is typically diagnosed by immunological and molecular methods such as polymerase chain reaction (PCR). Alternatively, mass spectrometry techniques may aid in confirming the presence of the pathogen or its toxins. However, because of the close genetic relationship between B. anthracis and other members of the Bacillus cereus sensu lato group (such as Bacillus cereus or Bacillus thuringiensis) mis- or questionable identification occurs frequently. Also, bacteriophages such as phage gamma (which is highly specific for B. anthracis) have been in use for anthrax diagnostics for many decades. Here we employed host cell-specific receptor binding proteins (RBP) of (pro)-phages, also known as tail or head fibers, to develop a microscopy-based approach for the facile, rapid and unambiguous detection of B. anthracis cells. For this, the genes of (putative) RBP from Bacillus phages gamma, Wip1, AP50c and from lambdoid prophage 03 located on the chromosome of B. anthracis were selected. Respective phage genes were heterologously expressed in Escherichia coli and purified as fusions with fluorescent proteins. B. anthracis cells incubated with either of the reporter fusion proteins were successfully surface-labeled. Binding specificity was confirmed as RBP fusion proteins did not bind to most isolates of a panel of other B. cereus s.l. species or to more distantly related bacteria. Remarkably, RBP fusions detected encapsulated B. anthracis cells, thus RBP were able to penetrate the poly-γ-d-glutamate capsule of B. anthracis. From these results we anticipate this RBP-reporter assay may be useful for rapid confirmative identification of B. anthracis.

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Genetic diversity and the presence of circular plasmids in Bacillus cereus isolates of clinical and environmental origin

2021

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The diversity of 61 Bacillus cereus strains isolated from different clinical specimens, food including raw milk and milk products, and water was evaluated. PFGE analysis could discriminate 61 distinct pulsotypes with similarity levels from 25 to 82%, which were divided into 13 clonal complexes. The similarity between clonal complexes was at least 40%. Clinical strains were divided into 10 clonal complexes, while the strains, isolated from milk, food and water were included in 9, 6 and 6 clonal complexes, respectively. Three clonal complexes were dominated by clinical isolates, while they were absent in two complexes. Bacterial isolates from foods, being a probable source of alimentary toxoinfection, showed low similarity to isolates from stool specimens. The isolates from both sources were classi ed together in only 4 out of 13 clonal complexes. The large circular and linear plasmids with the sizes between 50 and 200 kb were detected in 24 (39.3%) and 14 (23%) B. cereus strains, respectively. Thirteen (21.3%) strains contained only one plasmid, two plasmids were found in 6 (9.8%) of strains, and three or more plasmids were obtained in 5 (8.2%) of tested strains. The plasmids were con rmed in 30.8% and 40% of isolates from clinical specimens and food and milk samples, respectively. No clear correlation between the PFGE pro les, the source as well as plasmid content among all tested strains was observed.

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Evolutionary processes and environmental factors underlying the genetic diversity and lifestyles of Bacillus cereus group bacteria

Cited by 43 publications

References 90 publications

Phylogenetic Analysis of Bacillus cereus sensu lato Isolates from Commercial Bee Pollen Using tRNACys-PCR

Phylogenetic Analysis of Bacillus cereus sensu lato Isolates from Commercial Bee Pollen Using tRNACys-PCR

Rapid Microscopic Detection of Bacillus anthracis by Fluorescent Receptor Binding Proteins of Bacteriophages

Genetic diversity and the presence of circular plasmids in Bacillus cereus isolates of clinical and environmental origin

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