scholarly journals Identification and Pathogenic Potential of Bacillus cereus Strains Isolated from a Dairy Processing Plant Producing PDO Taleggio Cheese

2020 ◽  
Vol 8 (6) ◽  
pp. 949
Author(s):  
Erica Tirloni ◽  
Simone Stella ◽  
Cristian Bernardi ◽  
Diletta Mazzantini ◽  
Francesco Celandroni ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Processing Plant ◽  
Pathogenic Potential ◽  
Virulence Potential ◽  
Protected Designation Of Origin ◽  
Food Contact Surfaces ◽  
Low Levels ◽  
Cheese Curd ◽  
Hemolysin Bl ◽  
Encoding Genes

Low levels of contamination by Bacillus cereus at the cheese farm is essential for reducing any opportunity for growth prior consumption. In this study, B. cereus distribution in a plant producing Protected Designation of Origin Taleggio cheese was investigated and the virulence potential of the isolates was evaluated. Seventy-four samples were collected from Food and Non Food Contact Surfaces (FCS, NFCS), saline curd, and Taleggio. The eleven isolates were identified, typified, and clustered. Strains were tested for the production of hemolysins, hemolysin BL (HBL), phosphatidylcholine-specific phospholipase C (PC-PLC), proteases, and biofilm, and for the presence of chromosomal toxin-encoding genes (sph, plcA, cytK, entFM, bcet, entS, nheA, nheB, nheC). B. cereus was detected on NFCS, FCS, and curd, but not in Taleggio. The isolates were grouped into six clusters, and all produced PC-PLC, hemolysins, and proteases, and most of them HBL (66.7%). All the clusters harbored the nheA, sph, plcA, entFM, and cytK genes, and some also nheB (83.3%), nheC (66.7%), bcet (50.0%), and entS (66.7%). All strains showed biofilm-forming ability. Our data reveal possible contamination of production plants and cheese curd by potentially virulent B. cereus, but bacterial absence in Taleggio highlights the efficacy of a proper management of the production phases in assuring consumer’s protection.

Genetic Diversity, Antimicrobial Resistance, and Toxigenic Profiles of Bacillus cereus Strains Isolated from Sunsik

2012 ◽  
Vol 75 (2) ◽  
pp. 225-230 ◽  
Author(s):  
NARI LEE ◽  
JE MIN SUN ◽  
KYUNG YOON KWON ◽  
HYUN JUNG KIM ◽  
MINSEON KOO ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Fruits And Vegetables ◽  
Food Poisoning ◽  
Pcr Analysis ◽  
Contamination Level ◽  
Detection Rates ◽  
Its Gene ◽  
Hemolysin Bl ◽  
Encoding Genes ◽  
Element Sequence

Bacillus cereus can cause emetic and diarrheal types of food poisoning, but little study has been done on the toxins and toxin-encoding genes of B. cereus strains isolated from Sunsik, a Korean ready-to-eat food prepared from grains, fruits, and vegetables. In this study, 39 unique B. cereus strains were isolated and identified from Sunsik samples, with an average contamination level of 10 to 200 CFU/g. The detection rates of the hblACD, cytK, and bceT genes among all the strains were 48.7, 66.7, and 87.1%, respectively. All 39 B. cereus strains carried nheABC and entFM genes, and 36 strains also had the ces gene, which encodes an emetic toxin. Nonhemolytic enterotoxin and hemolysin BL enterotoxin were produced by 39 and 26 strains, respectively. The strains were separated into 13 profiles based on the presence or absence of toxins and their genes, as determined by antibody tests and PCR analysis. Profile 1 was the largest group, comprising 30.7% (12 of 39) of the B. cereus strains tested; these strains harbored all toxins and their genes. The B. cereus strains were susceptible to most of the antibiotics tested but were highly resistant to β-lactam antibiotics. The repetitive element sequence polymorphism PCR fingerprints of the B. cereus strains were not influenced by the presence of toxin genes or antibiotic resistance profiles. Our results suggest that B. cereus strains from Sunsik could cause either the diarrheal or emetic types of food poisoning because all strains isolated contained at least one toxin and its gene, although the level of B. cereus contamination in Sunsik was low.

scholarly journals Swarming Behavior of and Hemolysin BL Secretion by Bacillus cereus

2007 ◽  
Vol 73 (12) ◽  
pp. 4089-4093 ◽  
Author(s):  
Emilia Ghelardi ◽  
Francesco Celandroni ◽  
Sara Salvetti ◽  
Mara Ceragioli ◽  
Douglas J. Beecher ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Bacillus Cereus ◽  
Virulence Potential ◽  
Swarming Behavior ◽  
Hemolysin Bl

ABSTRACT An association between swarming and hemolysin BL secretion was observed in a collection of 42 Bacillus cereus isolates (P = 0.029). The highest levels of toxin were detected in swarmers along with swarm cell differentiation (P = 0.021), suggesting that swarming B. cereus strains may have a higher virulence potential than nonswarming strains.

High risk of potential diarrheagenic Bacillus cereus in diverse food products in Egypt

2021 ◽  
Author(s):  
Heba M. Amin ◽  
Mahmoud M. Tawfick
Keyword(s):  
Bacillus Cereus ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Health Management ◽  
Food Products ◽  
Bacterial Count ◽  
Contamination Level ◽  
Genetic Profile ◽  
Pathogenic Potential ◽  
Encoding Genes

Bacillus cereus is one of the important foodborne pathogens that can be found in various foodstuffs; causing diarrheal and/or emetic syndromes. This study aimed to evaluate the prevalence, antimicrobial susceptibility profile, pathogenic potential, and genotypic diversity of B. cereus isolated from diverse food products from markets in Cairo, Egypt. A total of 39 out of 165 food samples were positive for B. cereus (detection rate of 24%) with a contamination level ranged from 2 to 6 log CFU/g and a higher incidence of > 3 log bacterial count. Antimicrobial susceptibility testing showed that B. cereus isolates were fully sensitive to all tested antimicrobial agents except β-lactams. The pathogenic potential of the 39 B. cereus isolates was assessed by detecting and profiling the secreted virulence or toxin encoding genes including the chromosomal-carried genes hblA , bceT , plc , sph , nheA , entFM , cytK associated with the diarrheal syndrome and the plasmid-carried ces gene associated with the emetic syndrome. The most frequently detected  genes were hblA , nheA and entFM . All isolates harbored more than one of the diarrheal enterotoxins encoding genes with the genetic profile hblA-bceT-nheA-entFM-cytK-plc-sph was the most prevalent (in 20/39 isolates). The emetic toxin ces was not detected at all. ERIC-based analysis of the 20 B. cereus isolates harboring the prevalent genetic profile revelated that they were genetically distinct. In conclusion, the findings of this study provide useful information for public health management and serve as a warning of the potential risk of diarrheagenic B. cereus in diverse food products. Therefore, the consideration to extensively study the epidemiology of this food pathogen in Egypt is warranted. Additionally, strict procedures should be applied to monitor, protect, and safely handle food products, particularly ready to eat foodstuffs that are usually consumed without heat treatment.

scholarly journals Genetic Listeria monocytogenes Types in the Pork Processing Plant Environment: From Occasional Introduction to Plausible Persistence in Harborage Sites

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 717
Author(s):  
Niels Demaître ◽  
Geertrui Rasschaert ◽  
Lieven De Zutter ◽  
Annemie Geeraerd ◽  
Koen De Reu
Keyword(s):  
Genetic Diversity ◽  
Environmental Samples ◽  
Genetic Characterization ◽  
Processing Plant ◽  
Pfge Analysis ◽  
Food Contact ◽  
Plant Environment ◽  
Food Contact Surfaces ◽  
Contact Surfaces ◽  
Cleaning And Disinfection

The purpose of this study was to investigate the L. monocytogenes occurrence and genetic diversity in three Belgian pork cutting plants. We specifically aim to identify harborage sites and niche locations where this pathogen might occur. A total of 868 samples were taken from a large diversity of food and non-food contact surfaces after cleaning and disinfection (C&D) and during processing. A total of 13% (110/868) of environmental samples tested positive for L. monocytogenes. When looking in more detail, zone 3 non-food contact surfaces were contaminated more often (26%; 72/278) at typical harborage sites, such as floors, drains, and cleaning materials. Food contact surfaces (zone 1) were less frequently contaminated (6%; 25/436), also after C&D. PFGE analysis exhibited low genetic heterogeneity, revealing 11 assigned clonal complexes (CC), four of which (CC8, CC9, CC31, and CC121) were predominant and widespread. Our data suggest (i) the occasional introduction and repeated contamination and/or (ii) the establishment of some persistent meat-adapted clones in all cutting plants. Further, we highlight the importance of well-designed extensive sampling programs combined with genetic characterization to help these facilities take corrective actions to prevent transfer of this pathogen from the environment to the meat.

scholarly journals Investigating the Features of PDO Green Hams during Salting: Insights for New Markers and Genomic Regions in Commercial Hybrid Pigs

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 68
Author(s):  
Martina Zappaterra ◽  
Paolo Zambonelli ◽  
Cristina Schivazappa ◽  
Nicoletta Simoncini ◽  
Roberta Virgili ◽  
...  
Keyword(s):  
Weight Loss ◽  
Salt Content ◽  
Phenotypic Traits ◽  
Processing Plant ◽  
Lean Meat ◽  
New Associations ◽  
Meat Content ◽  
Protected Designation Of Origin ◽  
Genomic Regions

Protected Designation of Origin (PDO) dry-cured hams production is greatly dependent on raw meat quality. This study was performed to identify genetic markers associated with the quality of dry-cured ham. Carcass traits of 229 heavy pigs belonging to three commercial genetic lines were registered (weight, EUROP classification). Phenotypic traits (Semimembranosus muscle ultimate pH, ham weight and lean meat content, adsorbed salt) of the corresponding thighs, undergone PDO ham process in three different plants, were measured, using a fast and non-invasive technology. Green ham weight and lean meat percentage influenced the estimated salt content and the weight loss during salting, even if the processing plant greatly affected the variability of the measured ham traits. The genomic data were obtained with the GeneSeek Genomic Profiler (GGP) 70k HD Porcine Array, using the slaughter day and the sex of the animals in the statistical analyses. The phenotypic traits were associated with the genotypes through GenAbel software. The results showed that 18 SNPs located on nine porcine chromosomes were found to be associated with nine phenotypic traits, mainly related to ham weight loss during salting. New associations were found between markers in the genes Neural Precursor Cell Expressed Developmentally Down-Regulated 9 (NEDD9, SSC7), T-Cell Lymphoma Invasion and Metastasis 2 (TIAM2, SSC1), and the ham quality traits. After validation, these SNPs may be useful to improve the quality of thighs for the production of PDO dry-cured hams.

scholarly journals Multiple-Locus Sequence Typing and Analysis of Toxin Genes in Bacillus cereus Food-Borne Isolates

2007 ◽  
Vol 74 (3) ◽  
pp. 850-860 ◽  
Author(s):  
Barbara Cardazzo ◽  
Enrico Negrisolo ◽  
Lisa Carraro ◽  
Leonardo Alberghini ◽  
Tomaso Patarnello ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Bacillus Cereus ◽  
Reticulate Evolution ◽  
Sequence Information ◽  
Data Set ◽  
Group I ◽  
Food Borne ◽  
Public Data ◽  
Encoding Genes

ABSTRACT In the present study we characterized 47 food-borne isolates of Bacillus cereus using multilocus sequence typing (MLST). Newly determined sequences were combined with sequences available in public data banks in order to produce the largest data set possible. Phylogenetic analysis was performed on a total of 296 strains for which MLST sequence information is available, and three main lineages—I, II, and III—within the B. cereus complex were identified. With few exceptions, all food-borne isolates were in group I. The occurrence of horizontal gene transfer (HGT) among various strains was analyzed by several statistical methods, providing evidence of widespread lateral gene transfer within B. cereus. We also investigated the occurrence of toxin-encoding genes, focusing on their evolutionary history within B. cereus. Several patterns were identified, indicating a pivotal role of HGT in the evolution of toxin-encoding genes. Our results indicate that HGT is an important element in shaping the population structure of the B. cereus complex. The results presented here also provide strong evidence of reticulate evolution within the B. cereus complex.

scholarly journals Novel Effective Bacillus cereus Group Species “Bacillus clarus” Is Represented by Antibiotic-Producing Strain ATCC 21929 Isolated from Soil

mSphere ◽  
2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Marysabel Méndez Acevedo ◽  
Laura M. Carroll ◽  
Manjari Mukherjee ◽  
Emma Mills ◽  
Lingzi Xiaoli ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Hela Cells ◽  
Species Complex ◽  
Taxonomic Classification ◽  
Phenotypic Characterization ◽  
Pathogenic Potential ◽  
Cytotoxic Effects ◽  
Content Type ◽  
Group Species

ABSTRACT Gram-positive, spore-forming members of the Bacillus cereus group species complex are widespread in natural environments and display various degrees of pathogenicity. Recently, B. cereus group strain Bacillus mycoides Flugge ATCC 21929 was found to represent a novel lineage within the species complex, sharing a relatively low degree of genomic similarity with all B. cereus group genomes (average nucleotide identity [ANI] < 88). ATCC 21929 has been previously associated with the production of a patented antibiotic, antibiotic 60-6 (i.e., cerexin A); however, the virulence potential and growth characteristics of this lineage have never been assessed. Here, we provide an extensive genomic and phenotypic characterization of ATCC 21929, and we assess its pathogenic potential in vitro. ATCC 21929 most closely resembles Bacillus paramycoides NH24A2T (ANI and in silico DNA-DNA hybridization values of 86.70 and 34.10%, respectively). Phenotypically, ATCC 21929 does not possess cytochrome c oxidase activity and is able to grow at a range of temperatures between 15 and 43°C and a range of pH between 6 and 9. At 32°C, ATCC 21929 shows weak production of diarrheal enterotoxin hemolysin BL (Hbl) but no production of nonhemolytic enterotoxin (Nhe); at 37°C, neither Hbl nor Nhe is produced. Additionally, at 37°C, ATCC 21929 does not exhibit cytotoxic effects toward HeLa cells. With regard to fatty acid composition, ATCC 21929 has iso-C17:0 present in highest abundance. Based on the characterization provided here, ATCC 21929T (= PS00077AT = PS00077BT = PSU-0922T = BHPT) represents a novel effective B. cereus group species, which we propose as effective species “Bacillus clarus.” IMPORTANCE The B. cereus group comprises numerous closely related lineages with various degrees of pathogenic potential and industrial relevance. Species-level taxonomic classification of B. cereus group strains is important for risk evaluation and communication but remains challenging. Biochemical and phenotypic assays are often used to assign B. cereus group strains to species but are insufficient for accurate taxonomic classification on a genomic scale. Here, we show that antibiotic-producing ATCC 21929 represents a novel lineage within the B. cereus group that, by all metrics used to delineate prokaryotic species, exemplifies a novel effective species. Furthermore, we show that ATCC 21929 is incapable of producing enterotoxins Hbl and Nhe or exhibiting cytotoxic effects on HeLa cells at human body temperature in vitro. These results provide greater insight into the genomic and phenotypic diversity of the B. cereus group and may be leveraged to inform future public health and food safety efforts.

Molecular Identification and Virulence Potential of the Genus Aeromonas Isolated from Wild Rainbow Trout (Oncorhynchus mykiss) in Mexico

2019 ◽  
Vol 82 (10) ◽  
pp. 1706-1713 ◽  
Author(s):  
NYDIA E. REYES-RODRÍGUEZ ◽  
CELENE SALGADO-MIRANDA ◽  
IZANAMI T. FLORES-VALLE ◽  
MARICRUZ GONZÁLEZ-GÓMEZ ◽  
EDGARDO SORIANO-VARGAS ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Foodborne Pathogens ◽  
Sequence Similarity ◽  
Aeromonas Species ◽  
Pathogenic Potential ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Worldwide Distribution ◽  
Virulence Potential ◽  
Rpod Gene ◽  
Potential Pathogenicity

ABSTRACT The members of the Aeromonas genus are important foodborne pathogens, with a worldwide distribution. Wild rainbow trout, from the national protected area Santuario del Agua State Park, Corral de Piedra, were analyzed. Species of Aeromonas were isolated from the trout, and their pathogenic potential was analyzed based on different pathogenicity and virulence factors. The isolates were identified as A. allosaccharophila (n = 15), A. sobria (n = 8), A. veronii (n = 3), A. rivipollensis (n = 2), A. piscicola (n = 2), and A. popoffii (n = 1), by RNA polymerase sigma factor (rpoD) gene sequencing. Sequence similarity with the type strain was 92.2 to 99.6% for A. sobria isolates, 97.8 to 98.0% for A. allosaccharophila isolates, 99.2% for the A. popoffii isolate, 99.2 to 100% for A. piscicola isolates, and 98.2 to 99.2% for A. veronii isolates. Notably, isolates A30T2–gills and A30T2–spleen showed sequence similarity of 98.0% with strain A. media CECT 4232T and 99.0% with strain A. rivipollensis P2G1T. Virulence genes were detected by PCR at the following frequencies: fla and serine protease, 96.77%; aerA, 93.54%; aexT, 87.09%; lipases, 74.19%; ascV and ahyB, 67.74%; exu, 61.29%; act, 41.93%; ascF-G, 38.70%; lafA, 32.26%; alt, 6.46%; aopP, 9.67%; and ast, 3.23%. These results indicate that several Aeromonas species had the potential pathogenicity to infect wild rainbow trout in the waterway created by the Corral de Piedra dam, suggesting they could be an emerging zoonotic pathogen.

scholarly journals Expression of Bacillus cereus Virulence-Related Genes in an Ocular Infection-Related Environment

2020 ◽  
Vol 8 (4) ◽  
pp. 607 ◽  
Author(s):  
Phillip S. Coburn ◽  
Frederick C. Miller ◽  
Morgan A. Enty ◽  
Craig Land ◽  
Austin L. LaGrow ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Virulence Genes ◽  
Ex Vivo ◽  
Brain Heart Infusion ◽  
Luria Bertani ◽  
Ocular Infection ◽  
Rna Seq ◽  
Specific Factors ◽  
Low Levels

Bacillus cereus produces many factors linked to pathogenesis and is recognized for causing gastrointestinal toxemia and infections. B. cereus also causes a fulminant and often blinding intraocular infection called endophthalmitis. We reported that the PlcR/PapR system regulates intraocular virulence, but the specific factors that contribute to B. cereus virulence in the eye remain elusive. Here, we compared gene expression in ex vivo vitreous humor with expression in Luria Bertani (LB) and Brain Heart Infusion (BHI) broth by RNA-Seq. The expression of several cytolytic toxins in vitreous was less than or similar to levels observed in BHI or LB. Regulators of virulence genes, including PlcR/PapR, were expressed in vitreous. PlcR/PapR was expressed at low levels, though we reported that PlcR-deficient B. cereus was attenuated in the eye. Chemotaxis and motility genes were expressed at similar levels in LB and BHI, but at low to undetectable levels in vitreous, although motility is an important phenotype for B. cereus in the eye. Superoxide dismutase, a potential inhibitor of neutrophil activity in the eye during infection, was the most highly expressed gene in vitreous. Genes previously reported to be important to intraocular virulence were expressed at low levels in vitreous under these conditions, possibly because in vivo cues are required for higher level expression. Genes expressed in vitreous may contribute to the unique virulence of B. cereus endophthalmitis, and future analysis of the B. cereus virulome in the eye will identify those expressed in vivo, which could potentially be targeted to arrest virulence.

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