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

2020 ◽  
Vol 8 (4) ◽  
pp. 524
Author(s):  
José Luis Hernández Flores ◽  
Diana Salinas Landaverde ◽  
Yonuen Pacheco Huerta ◽  
Vania Lizeth Guerra Castillo ◽  
María de los Ángeles Barrios Sánchez ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Bacillus Cereus ◽  
Single Copy ◽  
Foodborne Illnesses ◽  
Regulatory Requirements ◽  
Bee Pollen ◽  
Enterotoxin Genes ◽  
Genes Encoding ◽  
Commercial Source ◽  
Bacillus Cereus Sensu Lato

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.

scholarly journals Prevalence and distribuion of staphylococcal enterotoxin genes among Staphylococcus aureus isolates from chicken and turkey carcasses in Algeria

2019 ◽  
Vol 69 (4) ◽  
pp. 1297 ◽  
Author(s):  
F. Mebkhout ◽  
L. Mezali ◽  
T. M. Hamdi ◽  
Z. Cantekin ◽  
Y. Ergun ◽  
...  
Keyword(s):  
Public Health ◽  
Staphylococcus Aureus ◽  
Multiplex Pcr ◽  
Staphylococcal Enterotoxin ◽  
Foodborne Illnesses ◽  
Biochemical Tests ◽  
Staphylococcal Enterotoxins ◽  
Enterotoxin Genes ◽  
Real Risk ◽  
Genes Encoding

This study is aimed to determine the prevalence of staphylococcus aureus (S.aureus) by biochemical tests in poultry carcasses. It is also intend to detect the distribution of genes for classical staphylococcal enterotoxins A, B, C, D and E (sea, seb, sec, sed and see) and for gene femA, specific for S.aureus species, using multiplex PCR. A total of 385 samples of neck skins from fresh poultry carcasses were collected during the period 2012-2013 from 16 different slaughterhouses located in the region of Algiers, Algeria. The overall prevalence of S.aureus in freshly slaughtered poultry carcasses was 41.56%, with an individual prevalence of 40.63% and 45.71% for chicken and turkey respectively. From the 95 strains of S.aureus identified by biochemical tests, 82 (86.32%) isolates were femA positive using multiplex PCR. The investigation has also revealed the presence of both enterotoxins B and D, with a predominance of seb (13.33%) followed by sed (1.67%), in the chicken carcasses while in turkey only sed was detected (4.55%) It has been found that strains of S.aureus of poultry origin can be enterotoxigenic with the predominance of genes encoding for enterotoxins seb in chicken and sed in turkey. As enterotoxins can be produced in adequate amounts to induce foodborne illnesses, these potential dangers must be considered in terms of a real risk to public health.

A Study To Assess the Numbers and Prevalence of Bacillus cereus and Its Toxins in Pasteurized Fluid Milk

2017 ◽  
Vol 80 (7) ◽  
pp. 1085-1089 ◽  
Author(s):  
Saleema Saleh-Lakha ◽  
Carlos G. Leon-Velarde ◽  
Shu Chen ◽  
Susan Lee ◽  
Kelly Shannon ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Raw Milk ◽  
Foodborne Illness ◽  
Cold Chain ◽  
Pasteurized Milk ◽  
High Temperature Short Time ◽  
Enterotoxin Genes ◽  
Genes Encoding ◽  
Short Time ◽  
Fluid Milk

ABSTRACT Bacillus cereus is a pathogenic adulterant of raw milk and can persist as spores and grow in pasteurized milk. The objective of this study was to determine the prevalence of B. cereus and its enterotoxins in pasteurized milk at its best-before date when stored at 4, 7, and 10°C. More than 5.5% of moderately temperature-abused products (stored at 7°C) were found to contain >105 CFU/mL B. cereus, and about 4% of them contained enterotoxins at a level that may result in foodborne illness; in addition, more than 31% of the products contained >105 CFU/mL B. cereus and associated enterotoxins when stored at 10°C. Results from a growth kinetic study demonstrated that enterotoxin production by B. cereus in pasteurized milk can occur in as short as 7 to 8 days of storage at 7°C. The higher B. cereus counts were associated with products containing higher butterfat content or with those produced using the conventional high-temperature, short-time pasteurization process. Traditional indicators, aerobic colony counts and psychrotrophic counts, were found to have no correlation with level of B. cereus in milk. The characterization of 17 representative B. cereus isolates from pasteurized milk revealed five toxigenic gene patterns, with all the strains carrying genes encoding for diarrheal toxins but not for an emetic toxin, and with one strain containing all four diarrheal enterotoxin genes (nheA, entFM, hblC, and cytK). The results of this study demonstrate the risks associated even with moderately temperature-abused pasteurized milk and the necessity of a controlled cold chain throughout the shelf life of fluid milk to enhance product safety and minimize foodborne illness.

scholarly journals Enterotoxin Gene Distribution and Genotypes of Bacillus cereus sensu lato Isolated from Cassava Starch

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 131
Author(s):  
Jennifer Sánchez-Chica ◽  
Margarita M. Correa ◽  
Angel E. Aceves-Diez ◽  
Laura M. Castañeda-Sandoval
Keyword(s):  
Bacillus Cereus ◽  
Raw Materials ◽  
Cassava Starch ◽  
Genomic Diversity ◽  
Enterotoxin Gene ◽  
Future Studies ◽  
Toxin Genes ◽  
Human Pathogenic Bacterium ◽  
Enterotoxin Genes ◽  
Bacillus Cereus Sensu Lato

Bacillus cereus is a human pathogenic bacterium found in foods with the potential to cause emesis and diarrhea. This study estimated the presence, toxigenic and genomic diversity of B. cereus s.l. obtained from cassava starch samples collected in bakeries and powdered food companies in Medellín (Colombia). Bacillus cereuss.l. was found in 43 of 75 (57%) cassava starch samples and 98 isolates were obtained. The nheABC, hblCDAB, cytK2, entFM and cesB toxin genes were detected by multiplex PCR and the most frequent operon was nheABC, whereas cesB gene was not found. Twelve toxigenic profiles were determined by the detection of toxin genes, and the most frequent profiles harbored all enterotoxin genes. A broad genomic diversity was detected according to GTG5-PCR fingerprinting results with 76 B. cereus s.l. grouped in sixteen clusters and the 22 isolates clustering separately. No relationship was observed between genomic background and toxigenic profiles. In general, the results showed a high genomic and enterotoxigenic diversity in B. cereus s.l. found in cassava starch. These results should incentive future studies to understand the distribution of B. cereus s.l. isolated on raw materials in comparison with finished products.

Population structure and toxin gene profiles of Bacillus cereus sensu lato isolated from flour products

2019 ◽  
Vol 366 (20) ◽  
Author(s):  
Patrick Kindle ◽  
Danai Etter ◽  
Roger Stephan ◽  
Sophia Johler
Keyword(s):  
Risk Assessment ◽  
Population Structure ◽  
Bacillus Thuringiensis ◽  
Bacillus Cereus ◽  
Toxin Gene ◽  
Type Iii ◽  
Gene Profiles ◽  
Enterotoxin Genes ◽  
Parasporal Crystals ◽  
Bacillus Cereus Sensu Lato

ABSTRACT Data on the occurrence, population structure and toxinogenic potential of Bacillus cereus sensu lato isolated from flour is essential to enable improved risk assessment. We aimed to provide data on the occurrence of B. cereus sensu lato in flour products at retail level. In addition, we screened the isolates for Bacillus thuringiensis and Bacillus cytotoxicus and determined population structure and toxin gene profiles. We screened 89 flour products for presence of B. cereus sensu lato, resulting in 75 positive samples (84%). We were able to show that the population structure of members of the B. cereus group isolated from flour is highly diverse. Isolates were assigned to panC types II (4%), III (21%), IV (39%) and V (36%). Production of parasporal crystals characteristic for Bacillus thuringiensis was detected in seven isolates assigned to panC type III, IV and V. No B. cytotoxicus were detected. Two of the isolates harbored ces encoding cereulide, which causes the emetic syndrome. Various enterotoxin genes were found, with all isolates harboring nhe, 75% of isolates harboring hbl and 51% of the isolates harboring cytK-2. Our findings suggest that toxinogenic B. cereus sensu lato are common in flour products at retail level.

scholarly journals Enigmatic Pilus-like Endospore Appendages of Bacillus cereus Group Species

2021 ◽  
Vol 22 (22) ◽  
pp. 12367
Author(s):  
Ephrem Debebe Zegeye ◽  
Brajabandhu Pradhan ◽  
Ann-Katrin Llarena ◽  
Marina Aspholm
Keyword(s):  
Bacillus Cereus ◽  
Bacillus Cereus Group ◽  
Functional Roles ◽  
Functional Studies ◽  
Cryo Electron Microscopy ◽  
Abiotic Surfaces ◽  
Genes Encoding ◽  
Group Species ◽  
Bacillus Cereus Sensu Lato

The endospores (spores) of many Bacillus cereus sensu lato species are decorated with multiple hair/pilus-like appendages. Although they have been observed for more than 50 years, all efforts to characterize these fibers in detail have failed until now, largely due to their extraordinary resilience to proteolytic digestion and chemical solubilization. A recent structural analysis of B. cereus endospore appendages (Enas) using cryo-electron microscopy has revealed the structure of two distinct fiber morphologies: the longer and more abundant “Staggered-type” (S-Ena) and the shorter “Ladder-like” type (L-Ena), which further enabled the identification of the genes encoding the S-Ena. Ena homologs are widely and uniquely distributed among B. cereus sensu lato species, suggesting that appendages play important functional roles in these species. The discovery of ena genes is expected to facilitate functional studies involving Ena-depleted mutant spores to explore the role of Enas in the interaction between spores and their environment. Given the importance of B. cereus spores for the food industry and in medicine, there is a need for a better understanding of their biological functions and physicochemical properties. In this review, we discuss the current understanding of the Ena structure and the potential roles these remarkable fibers may play in the adhesion of spores to biotic and abiotic surfaces, aggregation, and biofilm formation.

scholarly journals The genomic characterisation and comparison of Bacillus cereus strains isolated from indoor air

Gut Pathogens ◽  
2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Balakrishnan N. V. Premkrishnan ◽  
Cassie E. Heinle ◽  
Akira Uchida ◽  
Rikky W. Purbojati ◽  
Kavita K. Kushwaha ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Indoor Air ◽  
Nosocomial Infections ◽  
Food Poisoning ◽  
Foodborne Illnesses ◽  
Human Gut ◽  
Virulence Potential ◽  
Enterotoxin Genes ◽  
Genome Assemblies

Abstract Background Bacillus cereus is ubiquitous in nature, found in environments such as soil, plants, air, and part of the insect and human gut microbiome. The ability to produce endospores and biofilms contribute to their pathogenicity, classified in two types of food poisoning: diarrheal and emetic syndromes. Here we report gap-free, whole-genome sequences of two B. cereus strains isolated from air samples and analyse their emetic and diarrheal potential. Results Genome assemblies of the B. cereus strains consist of one chromosome and seven plasmids each. The genome size of strain SGAir0260 is 6.30-Mb with 6590 predicted coding sequences (CDS) and strain SGAir0263 is 6.47-Mb with 6811 predicted CDS. Macrosynteny analysis showed 99% collinearity between the strains isolated from air and 90.2% with the reference genome. Comparative genomics with 57 complete B. cereus genomes suggests these strains from air are closely associated with strains isolated from foodborne illnesses outbreaks. Due to virulence potential of B. cereus and its reported involvement in nosocomial infections, antibiotic resistance analyses were performed and confirmed resistance to ampicillin and fosfomycin, with susceptibility to ciprofloxacin, tetracycline and vancomycin in both strains. Conclusion Phylogenetic analysis combined with detection of haemolytic (hblA, hblC, and hblD) and non-haemolytic (nheA, nheB, and nheC) enterotoxin genes in both air-isolated strains point to the diarrheic potential of the air isolates, though not emetic. Characterization of these airborne strains and investigation of their potential disease-causing genes could facilitate identification of environmental sources of contamination leading to foodborne illnesses and nosocomial infections transported by air.

scholarly journals The assembled and annotated genome of the pigeon louse Columbicola columbae, a model ectoparasite

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
James G Baldwin-Brown ◽  
Scott M Villa ◽  
Anna I Vickrey ◽  
Kevin P Johnson ◽  
Sarah E Bush ◽  
...  
Keyword(s):  
Low Cost ◽  
Single Copy ◽  
Odorant Receptors ◽  
Rna Seq ◽  
Pediculus Humanus ◽  
Final Assembly ◽  
Oxford Nanopore ◽  
Genes Encoding ◽  
Host Parasite ◽  
G Protein Coupled

Abstract The pigeon louse Columbicola columbae is a longstanding and important model for studies of ectoparasitism and host-parasite coevolution. However, a deeper understanding of its evolution and capacity for rapid adaptation is limited by a lack of genomic resources. Here, we present a high-quality draft assembly of the C. columbae genome, produced using a combination of Oxford Nanopore, Illumina, and Hi-C technologies. The final assembly is 208 Mb in length, with 12 chromosome-size scaffolds representing 98.1% of the assembly. For gene model prediction, we used a novel clustering method (wavy_choose) for Oxford Nanopore RNA-seq reads to feed into the MAKER annotation pipeline. High recovery of conserved single-copy orthologs (BUSCOs) suggests that our assembly and annotation are both highly complete and highly accurate. Consistent with the results of the only other assembled louse genome, Pediculus humanus, we find that C. columbae has a relatively low density of repetitive elements, the majority of which are DNA transposons. Also similar to P. humanus, we find a reduced number of genes encoding opsins, G protein-coupled receptors, odorant receptors, insulin signaling pathway components, and detoxification proteins in the C. columbae genome, relative to other insects. We propose that such losses might characterize the genomes of obligate, permanent ectoparasites with predictable habitats, limited foraging complexity, and simple dietary regimes. The sequencing and analysis for this genome were relatively low cost, and took advantage of a new clustering technique for Oxford Nanopore RNAseq reads that will be useful to future genome projects.

A Family of Genes Clustered at the Triplo-lethal Locus of Drosophila melanogaster Has an Unusual Evolutionary History and Significant Synteny With Anopheles gambiae

Genetics ◽  
2003 ◽  
Vol 165 (2) ◽  
pp. 613-621 ◽  
Author(s):  
Douglas R Dorer ◽  
Jamie A Rudnick ◽  
Etsuko N Moriyama ◽  
Alan C Christensen
Keyword(s):  
Phylogenetic Analysis ◽  
Drosophila Melanogaster ◽  
Anopheles Gambiae ◽  
Evolutionary History ◽  
Codon Bias ◽  
Good Target ◽  
The Family ◽  
Genes Encoding ◽  
And Function ◽  
Gambiae Genome

Abstract Within the unique Triplo-lethal region (Tpl) of the Drosophila melanogaster genome we have found a cluster of 20 genes encoding a novel family of proteins. This family is also present in the Anopheles gambiae genome and displays remarkable synteny and sequence conservation with the Drosophila cluster. The family is also present in the sequenced genome of D. pseudoobscura, and homologs have been found in Aedes aegypti mosquitoes and in four other insect orders, but it is not present in the sequenced genome of any noninsect species. Phylogenetic analysis suggests that the cluster evolved prior to the divergence of Drosophila and Anopheles (250 MYA) and has been highly conserved since. The ratio of synonymous to nonsynonymous substitutions and the high codon bias suggest that there has been selection on this family both for expression level and function. We hypothesize that this gene family is Tpl, name it the Osiris family, and consider possible functions. We also predict that this family of proteins, due to the unique dosage sensitivity and the lack of homologs in noninsect species, would be a good target for genetic engineering or novel insecticides.

scholarly journals The Complete Chloroplast Genome of the Vulnerable Oreocharis esquirolii (Gesneriaceae): Structural Features, Comparative and Phylogenetic Analysis

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1692
Author(s):  
Li Gu ◽  
Ting Su ◽  
Ming-Tai An ◽  
Guo-Xiong Hu
Keyword(s):  
Phylogenetic Analysis ◽  
Sequence Similarity ◽  
Single Copy ◽  
Structural Features ◽  
Rrna Genes ◽  
Trna Genes ◽  
Sequencing Data ◽  
High Sequence Similarity ◽  
Plastid Genomes ◽  
Cp Genome

Oreocharis esquirolii, a member of Gesneriaceae, is known as Thamnocharis esquirolii, which has been regarded a synonym of the former. The species is endemic to Guizhou, southwestern China, and is evaluated as vulnerable (VU) under the International Union for Conservation of Nature (IUCN) criteria. Until now, the sequence and genome information of O. esquirolii remains unknown. In this study, we assembled and characterized the complete chloroplast (cp) genome of O. esquirolii using Illumina sequencing data for the first time. The total length of the cp genome was 154,069 bp with a typical quadripartite structure consisting of a pair of inverted repeats (IRs) of 25,392 bp separated by a large single copy region (LSC) of 85,156 bp and a small single copy region (SSC) of18,129 bp. The genome comprised 114 unique genes with 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. Thirty-one repeat sequences and 74 simple sequence repeats (SSRs) were identified. Genome alignment across five plastid genomes of Gesneriaceae indicated a high sequence similarity. Four highly variable sites (rps16-trnQ, trnS-trnG, ndhF-rpl32, and ycf 1) were identified. Phylogenetic analysis indicated that O. esquirolii grouped together with O. mileensis, supporting resurrection of the name Oreocharis esquirolii from Thamnocharisesquirolii. The complete cp genome sequence will contribute to further studies in molecular identification, genetic diversity, and phylogeny.

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