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Mostafa NF, Elkenany RM, Younis G. Characterization of Bacillus cereus isolated from contaminated foods with sequencing of virulence genes in Egypt. BRAZ J BIOL 2024; 84:e257516. [DOI: 10.1590/1519-6984.257516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 03/14/2022] [Indexed: 11/22/2022] Open
Abstract
Abstract The current study describes the presence of Bacillus cereus (B. cereus) in contaminated foods of animal source and ready for human consumption with highlighting on their virulence contributing factors by detection of its virulence genes in addition to identification of their sequencing. Three hundred sixty food samples categorized as (228) meat products and (132) milk products were examined for B. cereus isolation and all of these isolates were confirmed by biochemical tests. Eighteen strains obtained from different food samples were examined for the attendance of a number of virulence genes (nheA, cytK, entFM, bceT and hblC genes) using uniplex PCR method. Furthermore, the B. cereus strains were valued for the sequencing of described genes. Generally 24.44% (88/360) food samples classified as 11.11% (40/360) meat products and 13.33% (48/360) milk products carried B. cereus according to cultural and biochemical properties, with geometric mean (1.5×107±0.15 CFU/g or mL) . The highest counts (above 105 CFU/g or mL) were originated from milk products (with geometric mean 2.2×107±0.22 CFU/g or mL) more than meat products (with geometric mean 1×107±0.19 CFU/g or mL). The results revealed that all of our isolates had one or more virulence (enterotoxin) genes. In our research, the most predominant genes were nheA (100%), followed by cytK (61.11%), entFM (33.33%), bceT (11.11%) then hblC (5.56%). Molecular method detected that overall, 5 strains (27.78%) harbored only 1 gene (nheA), 7 strains (38.88%) harbored 2 genes which classified as 5 strains (27.78%) (nheA and cytK), 2 strains (11.11%) have (nheA and entFM). Moreover, 5 strains (27.78%) have 3 genes classified as 3 strains (16.67%) harbored (nheA, cytK and entFM), 1 strain (5.56%) had (nheA, cytK and hblC), and 1 strain (5.56%) had (nheA, cytK and bceT). Only 1 strain (5.56%) carried 4 tested virulence genes (nheA, cytK, entFM and bceT) genes. The most prevalent gene in meat and dairy foods was nheA (100%). The nucleotide sequences of (bceT, cytK, entFM, hblC and nheA genes) of B. cereus strains were deposited in GenBank under accession no. (MW911824, MW911825, MW911826, MW911827 and MW911828), respectively. Our study was established to indicate the presence of virulent B. cereus in meat and milk products ready for human consumption as a result of deficient hygienic actions. So, a plain for good hygienic measures should be modified to avoid causing serious health problems to human due to ingestion of such products.
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Liu B, Zhong X, Liu Z, Guan X, Wang Q, Qi R, Zhou X, Huang J. Probiotic Potential and Safety Assessment of Lactiplantibacillus plantarum cqf-43 and Whole-Genome Sequence Analysis. Int J Mol Sci 2023; 24:17570. [PMID: 38139398 PMCID: PMC10744225 DOI: 10.3390/ijms242417570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/13/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023] Open
Abstract
This study reports the whole-genome sequence of Lactiplantibacillus plantarum cqf-43 isolated from healthy sow feces. Based on genomic analysis, we performed a comprehensive safety assessment of strain cqf-43, using both in vitro and in vivo experiments, and explored its probiotic potential. The total genome length measures 3,169,201 bp, boasting a GC content of 44.59%. Through phylogenetic analyses, leveraging both 16S rRNA gene and whole-genome sequences, we confidently categorize strain cqf-43 as a member of Lactiplantibacillus. Genome annotation using Prokka unveiled a total of 3141 genes, encompassing 2990 protein-coding sequences, 71 tRNAs, 16 rRNAs, and 1 tmRNA. Functional annotations derived from COG and KEGG databases highlighted a significant abundance of genes related to metabolism, with a notable emphasis on carbohydrate utilization. The genome also revealed the presence of prophage regions and CRISPR-Cas regions while lacking virulence and toxin genes. Screening for antibiotic resistance genes via the CARD database yielded no detectable transferable resistance genes, effectively eliminating the potential for harmful gene transfer. It is worth highlighting that the virulence factors identified via the VFDB database primarily contribute to bolstering pathogen resilience in hostile environments. This characteristic is particularly advantageous for probiotics. Furthermore, the genome is devoid of menacing genes such as hemolysin, gelatinase, and biogenic amine-producing genes. Our investigation also unveiled the presence of three unannotated secondary metabolite biosynthetic gene clusters, as detected by the online tool antiSMASH, suggesting a great deal of unknown potential for this strain. Rigorous in vitro experiments confirmed tolerance of strain cqf-43 in the intestinal environment, its antimicrobial efficacy, sensitivity to antibiotics, absence of hemolysis and gelatinase activity, and its inability to produce biogenic amines. In addition, a 28-day oral toxicity test showed that the strain cqf-43 did not pose a health hazard in mice, further establishing it as a safe strain.
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Affiliation(s)
- Baiheng Liu
- Chongqing Academy of Animal Science, Chongqing 402460, China; (B.L.); (X.Z.); (Z.L.); (X.G.); (Q.W.); (R.Q.); (X.Z.)
- College of Animal Science and Technology, Southwest University, Chongqing 402460, China
| | - Xiaoxia Zhong
- Chongqing Academy of Animal Science, Chongqing 402460, China; (B.L.); (X.Z.); (Z.L.); (X.G.); (Q.W.); (R.Q.); (X.Z.)
- National Pig Technology Innovation Center, Chongqing 402460, China
| | - Zhiyun Liu
- Chongqing Academy of Animal Science, Chongqing 402460, China; (B.L.); (X.Z.); (Z.L.); (X.G.); (Q.W.); (R.Q.); (X.Z.)
- National Pig Technology Innovation Center, Chongqing 402460, China
| | - Xiaofeng Guan
- Chongqing Academy of Animal Science, Chongqing 402460, China; (B.L.); (X.Z.); (Z.L.); (X.G.); (Q.W.); (R.Q.); (X.Z.)
- National Pig Technology Innovation Center, Chongqing 402460, China
| | - Qi Wang
- Chongqing Academy of Animal Science, Chongqing 402460, China; (B.L.); (X.Z.); (Z.L.); (X.G.); (Q.W.); (R.Q.); (X.Z.)
- National Pig Technology Innovation Center, Chongqing 402460, China
| | - Renli Qi
- Chongqing Academy of Animal Science, Chongqing 402460, China; (B.L.); (X.Z.); (Z.L.); (X.G.); (Q.W.); (R.Q.); (X.Z.)
- National Pig Technology Innovation Center, Chongqing 402460, China
| | - Xiaorong Zhou
- Chongqing Academy of Animal Science, Chongqing 402460, China; (B.L.); (X.Z.); (Z.L.); (X.G.); (Q.W.); (R.Q.); (X.Z.)
- National Pig Technology Innovation Center, Chongqing 402460, China
| | - Jinxiu Huang
- Chongqing Academy of Animal Science, Chongqing 402460, China; (B.L.); (X.Z.); (Z.L.); (X.G.); (Q.W.); (R.Q.); (X.Z.)
- National Pig Technology Innovation Center, Chongqing 402460, China
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Çürek S, Geniş B, Özden Tuncer B, Tuncer Y. Prevalence, Toxin Genes, and Antibiotic Resistance Profiles of Bacillus cereus Isolates from Spices in Antalya and Isparta Provinces in Türkiye. Indian J Microbiol 2023; 63:549-561. [PMID: 38031610 PMCID: PMC10682334 DOI: 10.1007/s12088-023-01111-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 10/07/2023] [Indexed: 12/01/2023] Open
Abstract
Bacillus cereus is a pathogenic bacterium commonly found in nature and can produce toxins that cause food poisoning. This study aimed to detect the prevalence of B. cereus group bacteria in 50 unpackaged and 20 packaged spice samples frequently used as flavoring in Turkish cuisine, as well as investigate the presence of toxin genes and antibiotic resistance in the isolates. A total of 48 B. cereus group bacteria were isolated from 27 of 70 (38.57%) spice samples. The prevalence of B. cereus group bacteria in packaged (25%, 5/20) and unpackaged (44%, 22/50) spice samples did not differ significantly (P ˃ 0.05). All B. cereus group isolates were identified as B. cereus sensu stricto (B. cereus) using molecular methods. The hemolytic activity tests revealed that the most strains (44/48, 91.67%) are β-hemolytic. The distributions of toxin genes in isolates were investigated by PCR. It was determined that all isolates were identified to have 2-8 toxin genes, except B. cereus SBC3. The three most common toxin genes were found to be nheA (47/48, 97.92%), nheB (46/48, 95.83%), and entFM (46/48, 95.83%). All B. cereus isolates were susceptible to linezolid and vancomycin, while 35.42% (17/48) showed resistance to erythromycin. Multi-drug resistance (MDR) was detected in 8.3% (4/48) of B. cereus isolates, while 33.33% of the isolates showed multiple antibiotic resistance (MAR) index values higher than 0.2. The findings indicate that B. cereus may pose a health risk in packaged and unpackaged spices if present in high quantities. Therefore, the presence of B. cereus strains in both packaged and unpackaged spices should be monitored regarding consumer health and product safety.
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Affiliation(s)
- Sena Çürek
- Faculty of Engineering, Department of Food Engineering, Süleyman Demirel University, Isparta, Türkiye
| | - Burak Geniş
- Faculty of Engineering, Department of Food Engineering, Süleyman Demirel University, Isparta, Türkiye
| | - Banu Özden Tuncer
- Faculty of Engineering, Department of Food Engineering, Süleyman Demirel University, Isparta, Türkiye
| | - Yasin Tuncer
- Faculty of Engineering, Department of Food Engineering, Süleyman Demirel University, Isparta, Türkiye
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Buchacher T, Digruber A, Kranzler M, Del Favero G, Ehling-Schulz M. Bacillus cereus extracellular vesicles act as shuttles for biologically active multicomponent enterotoxins. Cell Commun Signal 2023; 21:112. [PMID: 37189133 PMCID: PMC10184354 DOI: 10.1186/s12964-023-01132-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 04/19/2023] [Indexed: 05/17/2023] Open
Abstract
BACKGROUND Extracellular vesicles (EVs) from Gram-positive bacteria have gained considerable importance as a novel transport system of virulence factors in host-pathogen interactions. Bacillus cereus is a Gram-positive human pathogen, causing gastrointestinal toxemia as well as local and systemic infections. The pathogenicity of enteropathogenic B. cereus has been linked to a collection of virulence factors and exotoxins. Nevertheless, the exact mechanism of virulence factor secretion and delivery to target cells is poorly understood. RESULTS Here, we investigate the production and characterization of enterotoxin-associated EVs from the enteropathogenic B. cereus strain NVH0075-95 by using a proteomics approach and studied their interaction with human host cells in vitro. For the first time, comprehensive analyses of B. cereus EV proteins revealed virulence-associated factors, such as sphingomyelinase, phospholipase C, and the three-component enterotoxin Nhe. The detection of Nhe subunits was confirmed by immunoblotting, showing that the low abundant subunit NheC was exclusively detected in EVs as compared to vesicle-free supernatant. Cholesterol-dependent fusion and predominantly dynamin-mediated endocytosis of B. cereus EVs with the plasma membrane of intestinal epithelial Caco2 cells represent entry routes for delivery of Nhe components to host cells, which was assessed by confocal microscopy and finally led to delayed cytotoxicity. Furthermore, we could show that B. cereus EVs elicit an inflammatory response in human monocytes and contribute to erythrocyte lysis via a cooperative interaction of enterotoxin Nhe and sphingomyelinase. CONCLUSION Our results provide insights into the interaction of EVs from B. cereus with human host cells and add a new layer of complexity to our understanding of multicomponent enterotoxin assembly, offering new opportunities to decipher molecular processes involved in disease development. Video Abstract.
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Affiliation(s)
- Tanja Buchacher
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Astrid Digruber
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Markus Kranzler
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Giorgia Del Favero
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
- Core Facility Multimodal Imaging, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
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Fraccalvieri R, Bianco A, Difato LM, Capozzi L, Del Sambro L, Simone D, Catanzariti R, Caruso M, Galante D, Normanno G, Palazzo L, Tempesta M, Parisi A. Toxigenic Genes, Pathogenic Potential and Antimicrobial Resistance of Bacillus cereus Group Isolated from Ice Cream and Characterized by Whole Genome Sequencing. Foods 2022; 11:foods11162480. [PMID: 36010481 PMCID: PMC9407285 DOI: 10.3390/foods11162480] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/22/2022] Open
Abstract
Bacillus cereus is isolated from a variety of foods where it may cause food spoilage and/or food poisoning due to its toxigenic and pathogenic nature. In this study, we identified members of B. cereus groups in 65% of the ice cream samples analyzed, which were characterized based on multi locus variable number tandem repeats analysis (MLVA) and whole genome sequencing (WGS). The MLVA revealed that 36 strains showed different allelic profiles. Analyses of WGS data enabled the identification of three members of the B. cereus group: B. cereus sensu stricto, B. mosaicus and B. thuringiensis. Based on the multi locus sequence typing (MLST) scheme, the strains were classified in 27 sequence types (STs), including ST26 that causes food poisoning. Toxin genes’ detection revealed the presence of the genes encoding nonhemolytic enterotoxin (NHE), hemolysin BL (HBL), cytotoxin K (cytK) and cereulide (ces) in 100%, 44%, 42% and 8% of the strains, respectively. The identification of eleven antimicrobial resistance (AMR) genes predicted the resistance to five different antimicrobials, and the resistance to beta-lactam antibiotics was confirmed with a phenotypic antimicrobial test. Taken together, the results showed that the B. cereus strains isolated from ice cream were a potential hazard for consumer safety.
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Affiliation(s)
- Rosa Fraccalvieri
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
| | - Angelica Bianco
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
- Experimental Zooprophylactic Institute of Apulia and Basilicata, 71121 Foggia, Italy
- Correspondence: ; Tel.: +39-080-4057858; Fax: +39-080-4057753
| | - Laura Maria Difato
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
| | - Loredana Capozzi
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
| | - Laura Del Sambro
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
| | - Domenico Simone
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
| | - Roberta Catanzariti
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
| | - Marta Caruso
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
| | - Domenico Galante
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
| | - Giovanni Normanno
- Department of Science of Agriculture, Food and the Environment (SAFE), University of Foggia, 71121 Foggia, Italy
| | - Lucia Palazzo
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
| | - Maria Tempesta
- Department of Veterinary Medicine, University Aldo Moro of Bari, Strada per Casamassima Km 3, 70010 Valenzano, Italy
| | - Antonio Parisi
- Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB), Via Manfredonia 20, 71121 Foggia, Italy
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Pereira da Silva M, Fernandes PÉ, de Jesus Pimentel-Filho N, José de Andrade N, Teodoro Alves RB, Eller MR, Luera Peña WE. Modelling adhesion and biofilm formation by Bacillus cereus isolated from dairy products as a function of pH, temperature and time. Int Dairy J 2022. [DOI: 10.1016/j.idairyj.2022.105472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Moteshareie H, Hassen WM, Dirieh Y, Groulx E, Dubowski JJ, Tayabali AF. Rapid, Sensitive, and Selective Quantification of Bacillus cereus Spores Using xMAP Technology. Microorganisms 2022; 10:microorganisms10071408. [PMID: 35889128 PMCID: PMC9319878 DOI: 10.3390/microorganisms10071408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 12/04/2022] Open
Abstract
Bacillus cereus is a spore-forming ubiquitous bacterium notable as a food poisoning agent. Detection of B. cereus spores using selective media is laborious and non-specific. Herein, the quantitative detection of B. cereus spores was investigated with commercial antibodies and published aptamer sequences. Several detection reagents were screened for affinity to Bacillus collagen-like protein A (BclA), an abundant exosporium glycoprotein. Sensitivity and selectivity toward B. cereus spores were tested using immunoassays and multi-analyte profiling (xMAP). A recombinant antibody developed in llama against BclA protein showed B. cereus spore selectivity and sensitivity between 102 and 105 spores/mL using xMAP. DNA aptamer sequences demonstrated sensitivity from 103 to 107 spores/mL and no cross-reaction to B. megaterium and B. subtilis. Selectivity for B. cereus spores was also demonstrated in a mixture of several diverse microorganisms and within a food sample with no compromise of sensitivity. As proof of concept for multiplexed measurement of human pathogens, B. cereus and three other microorganisms, E. coli, P. aeruginosa, and S. cerevisiae, were simultaneously detected using xMAP. These data support the development of a rapid, sensitive, and selective system for quantitation of B. cereus spores and multiplexed monitoring of human pathogens in complex matrices.
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Affiliation(s)
- Houman Moteshareie
- Department of Electrical and Computer Engineering, Interdisciplinary Institute for Technological Innovation (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (H.M.); (W.M.H.); (J.J.D.)
| | - Walid M. Hassen
- Department of Electrical and Computer Engineering, Interdisciplinary Institute for Technological Innovation (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (H.M.); (W.M.H.); (J.J.D.)
| | - Yasmine Dirieh
- Biotechnology Laboratory, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Environmental Health Centre, Health Canada, Ottawa, ON K1A 0K9, Canada; (Y.D.); (E.G.)
| | - Emma Groulx
- Biotechnology Laboratory, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Environmental Health Centre, Health Canada, Ottawa, ON K1A 0K9, Canada; (Y.D.); (E.G.)
| | - Jan J. Dubowski
- Department of Electrical and Computer Engineering, Interdisciplinary Institute for Technological Innovation (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (H.M.); (W.M.H.); (J.J.D.)
| | - Azam F. Tayabali
- Biotechnology Laboratory, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Environmental Health Centre, Health Canada, Ottawa, ON K1A 0K9, Canada; (Y.D.); (E.G.)
- Correspondence:
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Regulation of Enterotoxins Associated with Bacillus cereus Sensu Lato Toxicoinfection. Appl Environ Microbiol 2022; 88:e0040522. [PMID: 35730937 PMCID: PMC9275247 DOI: 10.1128/aem.00405-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Bacillus cereus sensu lato (s.l.) includes foodborne pathogens, as well as beneficial microorganisms, such as bioinsecticides. Some of the beneficial and commercially used B. cereus s.l. strains have been shown to carry enterotoxin genes, the products of which can cause toxicoinfection in humans. Furthermore, recent epidemiological reports indicated that some bioinsecticidal strains have been linked with foodborne illness outbreaks. This demonstrates the need for improved surveillance of B. cereus s.l., which includes characterization of isolates' virulence capacity. However, the prediction of virulence capacity of B. cereus s.l. strains is challenging. Genetic screening for enterotoxin gene presence has proven to be insufficient for accurate discrimination between virulent and avirulent strains, given that nearly all B. cereus s.l. strains carry at least one enterotoxin gene. Furthermore, complex regulatory networks governing the expression of enterotoxins, and potential synergistic interactions between enterotoxins and other virulence factors make the prediction of toxicoinfection based on isolates' genome sequences challenging. In this review, we summarize and synthesize the current understanding of the regulation of enterotoxins associated with the B. cereus s.l. toxicoinfection and identify gaps in the knowledge that need to be addressed to facilitate identification of genetic markers predictive of cytotoxicity and toxicoinfection.
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Esmkhani M, Shams S. Cutaneous infection due to Bacillus cereus: a case report. BMC Infect Dis 2022; 22:393. [PMID: 35448975 PMCID: PMC9022346 DOI: 10.1186/s12879-022-07372-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 04/11/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacillus cereus is a Gram-positive bacterium that can be found in various natural and human-made environments. It is often involved in gastrointestinal infections and food poisoning; yet, it can rarely cause serious non-gastrointestinal tract infections. CASE PRESENTATION Here we describe a case of B. cereus cutaneous infection of a wound on the hand of a young woman from a rural area in Iran. On admission, she had no systemic symptoms other than a cutaneous lesion. The identification of the causative agent was performed using sequencing of the 16S rRNA gene of the bacteria isolated from the wound. The isolated microorganism was identified as B. cereus. Targeted antibiotic therapy with ciprofloxacin was successful. DISCUSSION AND CONCLUSION Although non-intestinal infections caused by B. cereus are rare, it should be taken into consideration that this organism might also cause infections in other parts of the body.
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Affiliation(s)
| | - Saeed Shams
- Cellular and Molecular Research Center, Qom University of Medical Sciences, Qom, Iran.
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10
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Jessberger N, Diedrich R, Janowski R, Niessing D, Märtlbauer E. Presence and function of Hbl B', the fourth protein component encoded by the hbl operon in Bacillus cereus. Virulence 2022; 13:483-501. [PMID: 35291913 PMCID: PMC8932913 DOI: 10.1080/21505594.2022.2046951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The genes hblC, hblD and hblA encode the components Hbl L2, L1 and B of the pore forming enterotoxin haemolysin BL of Bacillus cereus. Two variants of the operon existand the more common one additionally contains hblB downstream of hblCDA. Up to now, it was completely unclear whether the corresponding protein, Hbl B', is widely expressed among B. cereus strains and if it has a distinct function. In the present study, it was shown that the hblB gene is indeed expressed and the Hbl B' protein is secreted by nearly all analysed B. cereus strains. For the latter, a detection system was developed based on monoclonal antibody 11A5. Further, a distinct reduction of cytotoxic and haemolytic activity was observed when recombinant (r)Hbl B' was applied simultaneously with L2, L1 and B. This effect was due to direct interaction of rHbl B' with L1. D-6B. cereusAltogether, we present the first simple tool for the detection of Hbl B' in B. cereus culture supernatants. Moreover, an important regulatory function of Hbl B' in the mechanism of Hbl was determined, which is best described as an additional control of complex formation, balancing the amounts of Hbl B-L1 complexes and the corresponding free subunits.
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Affiliation(s)
- Nadja Jessberger
- Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Richard Diedrich
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Oberschleißheim, Germany
| | - Robert Janowski
- Institute of Structural Biology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Dierk Niessing
- Institute of Structural Biology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany.,Institute of Pharmaceutical Biotechnology, Ulm University, Ulm, Germany
| | - Erwin Märtlbauer
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Oberschleißheim, Germany
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Jang YJ, Gwon HM, Jeong WS, Yeo SH, Kim SY. Safety Evaluation of Weissella cibaria JW15 by Phenotypic and Genotypic Property Analysis. Microorganisms 2021; 9:microorganisms9122450. [PMID: 34946052 PMCID: PMC8704421 DOI: 10.3390/microorganisms9122450] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 12/02/2022] Open
Abstract
Weissella cibaria is one of the bacteria in charge of the initial fermentation of kimchi and has beneficial effects such as immune-modulating, antagonistic, and antioxidant activities. In our study, we aimed to estimate the safety of W. cibaria JW15 for the use of probiotics according to international standards based on phenotypic (antibiotic resistance, hemolysis, and toxic metabolite production) and genotypic analysis (virulence genes including antibiotic resistance genes). The results of the safety assessment on W. cibaria JW15 were as follows; (1) antibiotic resistance genes (ARGs) (kanamycin and vancomycin etc.) were intrinsic characteristics; (2) There were no acquired virulence genes including Cytolysin (cylA), aggregation substance (asa1), Hyaluronidase (hyl), and Gelatinase (gelE); (3) this strain also lacked β-hemolysis and the production of toxic metabolites (D-lactate and bile salt deconjugation). Consequently, W. cibaria JW15 is expected to be applied as a functional food ingredient in the food market.
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Ramm F, Stech M, Zemella A, Frentzel H, Kubick S. The Pore-Forming Hemolysin BL Enterotoxin from Bacillus cereus: Subunit Interactions in Cell-Free Systems. Toxins (Basel) 2021; 13:toxins13110807. [PMID: 34822591 PMCID: PMC8623112 DOI: 10.3390/toxins13110807] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/05/2021] [Accepted: 11/12/2021] [Indexed: 11/16/2022] Open
Abstract
The tripartite enterotoxin Hemolysin BL (Hbl) has been widely characterized as a hemolytic and cytotoxic virulence factor involved in foodborne diarrheal illness caused by Bacillus cereus. Previous studies have described the formation of the Hbl complex and aimed to identify the toxin’s mode of action. In this study, we analyzed the assembly of Hbl out of its three individual subunits L1, L2 and B in a soluble as well as a putative membrane bound composition using a Chinese hamster ovary (CHO) cell-free system. Subunits were either coexpressed or synthesized individually in separate cell-free reactions and mixed together afterwards. Hemolytic activity of cell-free synthesized subunits was demonstrated on 5% sheep blood agar and identified both synthesis procedures, coexpression as well as individual synthesis of each subunit, as functional for the synthesis of an active Hbl complex. Hbl’s ability to perforate cell membranes was evaluated using a propidium iodide uptake assay. These data suggested that coexpressed Hbl subunits augmented cytotoxic activity with increasing concentrations. Further, a pre-pore-complex of L1-L2 showed cytotoxic effects suggesting the possibility of an interaction between the cell membrane and the pre-pore-complex. Overall, this study shows that cell-free protein synthesis is a fast and efficient way to study the assembly of multiple protein subunits in soluble as well as vesicular fractions.
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Affiliation(s)
- Franziska Ramm
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany; (F.R.); (M.S.); (A.Z.)
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Marlitt Stech
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany; (F.R.); (M.S.); (A.Z.)
| | - Anne Zemella
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany; (F.R.); (M.S.); (A.Z.)
| | - Hendrik Frentzel
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany;
| | - Stefan Kubick
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany; (F.R.); (M.S.); (A.Z.)
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
- Faculty of Health Sciences, Joint Faculty of the Brandenburg University of Technology Cottbus–Senftenberg, Brandenburg Medical School Theodor Fontane and the University of Potsdam, 14476 Potsdam, Germany
- Correspondence: ; Tel.: +49-331-58-187-306; Fax: +49-331-58-187-199
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13
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Gamage NW, Bamforth J, Ashfaq T, Bernard K, Gräfenhan T, Walkowiak S. Profiling of Bacillus cereus on Canadian grain. PLoS One 2021; 16:e0259209. [PMID: 34735500 PMCID: PMC8568128 DOI: 10.1371/journal.pone.0259209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 10/14/2021] [Indexed: 11/18/2022] Open
Abstract
Microorganisms that cause foodborne illnesses challenge the food industry; however, environmental studies of these microorganisms on raw grain, prior to food processing, are uncommon. Bacillus cereus sensu lato is a diverse group of bacteria that is common in our everyday environment and occupy a wide array of niches. While some of these bacteria are beneficial to agriculture due to their entomopathogenic properties, others can cause foodborne illness; therefore, characterization of these bacteria is important from both agricultural and food safety standpoints. We performed a survey of wheat and flax grain samples in 2018 (n = 508) and 2017 (n = 636) and discovered that B. cereus was present in the majority of grain samples, as 56.3% and 85.2%, in two years respectively. Whole genome sequencing and comparative genomics of 109 presumptive B. cereus isolates indicates that most of the isolates were closely related and formed two genetically distinct groups. Comparisons to the available genomes of reference strains suggested that the members of these two groups are not closely related to strains previously reported to cause foodborne illness. From the same data set, another, genetically more diverse group of B. cereus was inferred, which had varying levels of similarity to previously reported strains that caused disease. Genomic analysis and PCR amplification of genes linked to toxin production indicated that most of the isolates carry the genes nheA and hbID, while other toxin genes and gene clusters, such as ces, were infrequent. This report of B. cereus on grain from Canada is the first of its kind and demonstrates the value of surveillance of bacteria naturally associated with raw agricultural commodities such as cereal grain and oilseeds.
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Affiliation(s)
| | - Janice Bamforth
- Canadian Grain Commission, Government of Canada, Winnipeg, Canada
| | - Tehreem Ashfaq
- Canadian Grain Commission, Government of Canada, Winnipeg, Canada
| | - Kathryn Bernard
- Public Health Agency of Canada, National Microbiology Laboratory, Government of Canada, Winnipeg, Canada
| | - Tom Gräfenhan
- Canadian Grain Commission, Government of Canada, Winnipeg, Canada
- Public Health Agency of Canada, National Microbiology Laboratory, Government of Canada, Winnipeg, Canada
- * E-mail: (TG); (SW)
| | - Sean Walkowiak
- Canadian Grain Commission, Government of Canada, Winnipeg, Canada
- * E-mail: (TG); (SW)
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14
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Kwon YJ, Chun BH, Jung HS, Chu J, Joung H, Park SY, Kim BK, Jeon CO. Safety Assessment of Lactiplantibacillus (formerly Lactobacillus) plantarum Q180. J Microbiol Biotechnol 2021; 31:1420-1429. [PMID: 34373437 PMCID: PMC9705903 DOI: 10.4014/jmb.2106.06066] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/03/2021] [Accepted: 08/09/2021] [Indexed: 12/15/2022]
Abstract
The safety of the probiotic strain Q180, which exerts postprandial lipid-lowering effects, was bioinformatically and phenotypically evaluated. The genome of strain Q180 was completely sequenced, and single circular chromosome of 3,197,263 bp without any plasmid was generated. Phylogenetic and related analyses using16S rRNA gene and whole-genome sequences revealed that strain Q180 is a member of Lactiplantibacillus (Lp., formerly Lactobacillus) plantarum. Antimicrobial resistance (AMR) genes were bioinformatically analyzed using all Lp. plantarum genomes available in GenBank, which showed that AMR genes are present differently depending on Lp. plantarum strains. Bioinformatic analysis demonstrated that some mobile genetic elements such as prophages and insertion sequences were identified in the genome of strain Q180, but because they did not contain harmful genes such as AMR genes and virulence factor (VF)- and toxin-related genes, it was suggested that there is no transferability of harmful genes. The minimum inhibition concentrations of seven tested antibiotics suggested by the European Food Safety Authority guidelines were slightly lower than or equal to the microbiological cut-off values for Lp. plantarum. Strain Q180 did not show hemolytic and gelatinase activities and biogenic amine-producing ability. Taken together, this study demonstrated the safety of strain Q180 in terms of absence of AMR genes and VF- and toxin-related genes as a probiotic strain.
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Affiliation(s)
- Yoo Jin Kwon
- Probiotics Research Laboratory, Chong Kun Dang Bio Research Institute (CKDBIO), Gyeonggi 15064, Republic of Korea
| | - Byung Hee Chun
- Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Hye Su Jung
- Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jaeryang Chu
- Probiotics Research Laboratory, Chong Kun Dang Bio Research Institute (CKDBIO), Gyeonggi 15064, Republic of Korea
| | - Hyunchae Joung
- Probiotics Research Laboratory, Chong Kun Dang Bio Research Institute (CKDBIO), Gyeonggi 15064, Republic of Korea
| | - Sung Yurb Park
- Probiotics Research Laboratory, Chong Kun Dang Bio Research Institute (CKDBIO), Gyeonggi 15064, Republic of Korea
| | - Byoung Kook Kim
- Probiotics Research Laboratory, Chong Kun Dang Bio Research Institute (CKDBIO), Gyeonggi 15064, Republic of Korea
| | - Che Ok Jeon
- Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea,Corresponding author Phone: +82-2-820-5864 E-mail:
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15
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Butcher M, Puiu D, Romagnoli M, Carroll KC, Salzberg SL, Nauen DW. Rapidly fatal infection with Bacillus cereus/thuringiensis: genome assembly of the responsible pathogen and consideration of possibly contributing toxins. Diagn Microbiol Infect Dis 2021; 101:115534. [PMID: 34601446 PMCID: PMC9716716 DOI: 10.1016/j.diagmicrobio.2021.115534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 10/20/2022]
Abstract
Bloodstream infection with Bacillus cereus/thuringiensis can be life threatening, particularly in patients who are severely immunocompromised. In this report we describe a case that progressed from asymptomatic to fatal over approximately 5 hours despite extensive resuscitation efforts. We identify the pathogen and assemble its genome, in which we find genes for toxins that may have contributed to the precipitous demise. In the context of this and other cases we discuss the possible indication for rapid appropriate antibiotic administration and potentially antitoxin treatment or toxin removal in fulminant illness in immunocompromised patients.
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Affiliation(s)
- Monica Butcher
- Department of Pathology and Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Daniela Puiu
- Department of Pathology and Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Mark Romagnoli
- Department of Pathology and Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Karen C Carroll
- Department of Pathology and Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Steven L Salzberg
- Department of Pathology and Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
| | - David W Nauen
- Department of Pathology and Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA.
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16
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Cheng LW, Rao S, Poudyal S, Wang PC, Chen SC. Genotype and virulence gene analyses of Bacillus cereus group clinical isolates from the Chinese softshell turtle (Pelodiscus sinensis) in Taiwan. JOURNAL OF FISH DISEASES 2021; 44:1515-1529. [PMID: 34125451 DOI: 10.1111/jfd.13473] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 06/12/2023]
Abstract
Chinese softshell turtles (Pelodiscus sinensis) (CST) are susceptible to infections by bacteria belonging to the Bacillus cereus group (Bcg). Bcg includes several closely related species, two of which, B. cereus and B. thuringiensis, are pathogens of aquatic animals or insects. In the present study, we collected 57 Bcg isolates obtained from diseased CST from 2016 to 2019 in Kaohsiung and Pingtung, the areas with the most CST farms in Taiwan. All isolates were divided into four genotypes with two restriction enzymes, SmaI and NotI, by pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). Representative isolates from each genotype were subjected to phylogenetic tree analysis using 16S rDNA and pyruvate carboxylase genes as phylogenetic markers, and these CST isolates appeared in different clades. PCR was performed targeting six selected virulence genes, four of which were detected in CST isolates, including cytotoxin K (1/57), hblC of the haemolysin BL complex (46/57), nheA of the non-haemolytic enterotoxin complex (52/57) and enterotoxin FM (57/57), whereas cereulide synthetase and cereulide peptide synthase-like genes were not detected in any isolates.
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Affiliation(s)
- Li-Wu Cheng
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- College of Veterinary Medicine, Southern Taiwan Fish Diseases Research Centre, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shreesha Rao
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Sayuj Poudyal
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Pei-Chi Wang
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- College of Veterinary Medicine, Southern Taiwan Fish Diseases Research Centre, National Pingtung University of Science and Technology, Pingtung, Taiwan
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Centre for Fish Vaccine and Diseases, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shih-Chu Chen
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- College of Veterinary Medicine, Southern Taiwan Fish Diseases Research Centre, National Pingtung University of Science and Technology, Pingtung, Taiwan
- International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Centre for Fish Vaccine and Diseases, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Centre for Animal Biologics, National Pingtung University of Science and Technology, Pingtung, Taiwan
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17
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Schmid PJ, Maitz S, Kittinger C. Bacillus cereus in Packaging Material: Molecular and Phenotypical Diversity Revealed. Front Microbiol 2021; 12:698974. [PMID: 34326827 PMCID: PMC8314860 DOI: 10.3389/fmicb.2021.698974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/21/2021] [Indexed: 11/13/2022] Open
Abstract
The Bacillus cereus group has been isolated from soils, water, plants and numerous food products. These species can produce a variety of toxins including several enterotoxins [non-hemolytic enterotoxin (Nhe), hemolysin BL (Hbl), cytotoxin K, and enterotoxin FM], the emetic toxin cereulide and insecticidal Bt toxins. This is the first study evaluating the presence of B. cereus in packaging material. Among 75 different isolates, four phylogenetic groups were detected (II, III, IV, and VI), of which the groups III and IV were the most abundant with 46.7 and 41.3%, respectively. One isolate was affiliated to psychrotolerant group VI. Growth experiments showed a mesophilic predominance. Based on PCR analysis, nhe genes were detectable in 100% of the isolates, while hbl genes were only found in 50.7%. The cereulide encoding gene was found in four out of 75 isolates, no isolate carried a crystal toxin gene. In total, thirteen different toxin gene profiles were identified. We showed that a variety of B. cereus group strains can be found in packaging material. Here, this variety lies in the presence of four phylogenetic groups, thirteen toxin gene profiles, and different growth temperatures. The results suggest that packaging material does not contain significant amounts of highly virulent strains, and the low number of cereulide producing strains is in accordance with other results.
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Affiliation(s)
- Paul Jakob Schmid
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Stephanie Maitz
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Clemens Kittinger
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
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18
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Jovanovic J, Ornelis VFM, Madder A, Rajkovic A. Bacillus cereus food intoxication and toxicoinfection. Compr Rev Food Sci Food Saf 2021; 20:3719-3761. [PMID: 34160120 DOI: 10.1111/1541-4337.12785] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 05/13/2021] [Accepted: 05/15/2021] [Indexed: 12/12/2022]
Abstract
Bacillus cereus is one of the leading etiological agents of toxin-induced foodborne diseases. Its omnipresence in different environments, spore formation, and its ability to adapt to varying conditions and produce harmful toxins make this pathogen a health hazard that should not be underestimated. Food poisoning by B. cereus can manifest itself as an emetic or diarrheal syndrome. The former is caused by the release of the potent peptide toxin cereulide, whereas the latter is the result of proteinaceous enterotoxins (e.g., hemolysin BL, nonhemolytic enterotoxin, and cytotoxin K). The final harmful effect is not only toxin and strain dependent, but is also affected by the stress responses, accessory virulence factors, and phenotypic properties under extrinsic, intrinsic, and explicit food conditions and host-related environment. Infamous portrait of B. cereus as a foodborne pathogen, as well as a causative agent of nongastrointestinal infections and even nosocomial complications, has inspired vast volumes of multidisciplinary research in food and clinical domains. As a result, extensive original data became available asking for a new, both broad and deep, multifaceted look into the current state-of-the art regarding the role of B. cereus in food safety. In this review, we first provide an overview of the latest knowledge on B. cereus toxins and accessory virulence factors. Second, we describe the novel taxonomy and some of the most pertinent phenotypic characteristics of B. cereus related to food safety. We link these aspects to toxin production, overall pathogenesis, and interactions with its human host. Then we reflect on the prevalence of different toxinotypes in foods opening the scene for epidemiological aspects of B. cereus foodborne diseases and methods available to prevent food poisoning including overview of the different available methods to detect B. cereus and its toxins.
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Affiliation(s)
- Jelena Jovanovic
- Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Vincent F M Ornelis
- Department of Organic and Macromolecular Chemistry, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Annemieke Madder
- Department of Organic and Macromolecular Chemistry, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Andreja Rajkovic
- Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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19
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Wan X, Geng P, Sun J, Yuan Z, Hu X. Characterization of two newly isolated bacteriophages PW2 and PW4 and derived endolysins with lysis activity against Bacillus cereus group strains. Virus Res 2021; 302:198489. [PMID: 34146612 DOI: 10.1016/j.virusres.2021.198489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/05/2021] [Accepted: 06/11/2021] [Indexed: 01/31/2023]
Abstract
This study characterized two novel Siphoviridae phages, PW2 and PW4, that can infect 52% and 44% of the tested Bacillus cereus group isolates and display relatively high activity against four cereulide-producing isolates belonging to B. weihenstephanensis and B. paranthracis. The genome sequences of PW2 and PW4 are similar to six known phages infecting B. cereus group isolates, which can be classified into two conserved groups, with the PW2 genome harboring conserved coding sequences (CDSs) from both groups. Two phage-derived endolysins, LysPW2 and LysPW4, which are predicted to encode N-acetylmuramoyl-L-alanine amidase, and their enzymatically active domains (EADs), LysPW2-EAD and LysPW4-EAD, were heterologously expressed. Both LysPW2 and LysPW4, especially the former, show a much wider host range than the phages, albeit still limited to the B. cereus group for the tested bacteria. The optimal temperature and pH for LysPW2 ability is 37 °C and pH 8.0 and for LysPW4 is 50 °C and pH 9.0. Neither LysPW2-EAD nor LysPW4-EAD show any lytic activity against vegetative cells of the tested B. cereus group isolates but can inhibit germination in 66.3% and 65.7% of spores, respectively. In addition, both LysPW2-EAD and LysPW4-EAD exhibit spore-binding capabilities.
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Affiliation(s)
- Xiaofu Wan
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430070, China; University of the Chinese Academy of Sciences, Beijing 100039, China; College of Life Science, South-Central University for Nationalities, Wuhan 430074, China
| | - Peiling Geng
- College of Life Science, South-Central University for Nationalities, Wuhan 430074, China
| | - Jiahui Sun
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430070, China; University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Zhiming Yuan
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430070, China.
| | - Xiaomin Hu
- College of Life Science, South-Central University for Nationalities, Wuhan 430074, China.
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20
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Fulminant Necrotizing Soft-tissue Infection in an Extremely Low Gestational Age Infant. Pediatr Infect Dis J 2021; 40:e189-e190. [PMID: 33480664 DOI: 10.1097/inf.0000000000003064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We report a case of rapidly progressive necrotizing skin and soft-tissue infection caused by Bacillus cereus in an extremely low for gestational age infant. This case reminds clinicians to consider this opportunistic pathogen as the etiologic agent in fulminant necrotizing infections in vulnerable hosts, and to institute appropriate therapy in a timely fashion.
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21
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Phenotypic properties and genotyping analysis of Bacillus cereus group isolates from dairy and potato products. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.110853] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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22
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Worthy HL, Williamson LJ, Auhim HS, Leppla SH, Sastalla I, Jones DD, Rizkallah PJ, Berry C. The Crystal Structure of Bacillus cereus HblL 1. Toxins (Basel) 2021; 13:253. [PMID: 33807365 PMCID: PMC8065917 DOI: 10.3390/toxins13040253] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/26/2021] [Accepted: 03/29/2021] [Indexed: 02/07/2023] Open
Abstract
The Hbl toxin is a three-component haemolytic complex produced by Bacillus cereus sensu lato strains and implicated as a cause of diarrhoea in B. cereus food poisoning. While the structure of the HblB component of this toxin is known, the structures of the other components are unresolved. Here, we describe the expression of the recombinant HblL1 component and the elucidation of its structure to 1.36 Å. Like HblB, it is a member of the alpha-helical pore-forming toxin family. In comparison to other members of this group, it has an extended hydrophobic beta tongue region that may be involved in pore formation. Molecular docking was used to predict possible interactions between HblL1 and HblB, and suggests a head to tail dimer might form, burying the HblL1 beta tongue region.
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Affiliation(s)
- Harley L. Worthy
- School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3AX, UK; (H.L.W.); (L.J.W.); (H.S.A.); (D.D.J.)
- The Henry Wellcome Building for Biocatalysis, Exeter University, Stocker Road, Exeter EX4 4QD, UK
| | - Lainey J. Williamson
- School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3AX, UK; (H.L.W.); (L.J.W.); (H.S.A.); (D.D.J.)
| | - Husam Sabah Auhim
- School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3AX, UK; (H.L.W.); (L.J.W.); (H.S.A.); (D.D.J.)
- Department of Biology, College of Science, University of Baghdad, Baghdad, Iraq
| | - Stephen H. Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (S.H.L.); (I.S.)
| | - Inka Sastalla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (S.H.L.); (I.S.)
- Scientific Review Program, Division of Extramural Activities, NIAID, NIH, Rockville, MD 20892, USA
| | - D. Dafydd Jones
- School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3AX, UK; (H.L.W.); (L.J.W.); (H.S.A.); (D.D.J.)
| | | | - Colin Berry
- School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3AX, UK; (H.L.W.); (L.J.W.); (H.S.A.); (D.D.J.)
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23
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Churchill-Angus AM, Schofield THB, Marlow TR, Sedelnikova SE, Wilson JS, Rafferty JB, Baker PJ. Characterisation of a tripartite α-pore forming toxin from Serratia marcescens. Sci Rep 2021; 11:6447. [PMID: 33742033 PMCID: PMC7979752 DOI: 10.1038/s41598-021-85726-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 03/03/2021] [Indexed: 01/31/2023] Open
Abstract
Tripartite members of the ClyA family of α-PFTs have recently been identified in a number of pathogenic Gram-negative bacteria, including the human pathogen Serratia marcescens. Structures of a Gram-negative A component and a tripartite α-PFT complete pore are unknown and a mechanism for pore formation is still uncertain. Here we characterise the tripartite SmhABC toxin from S. marcescens and propose a mechanism of pore assembly. We present the structure of soluble SmhA, as well as the soluble and pore forms of SmhB. We show that the β-tongue soluble structure is well conserved in the family and propose two conserved latches between the head and tail domains that are broken on the soluble to pore conformational change. Using the structures of individual components, sequence analysis and docking predictions we illustrate how the A, B and C protomers would assemble on the membrane to produce a complete tripartite α-PFT pore.
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Affiliation(s)
- Alicia M Churchill-Angus
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, South Yorkshire, UK
| | - Thomas H B Schofield
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, South Yorkshire, UK
- Current address: Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Thomas R Marlow
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, South Yorkshire, UK
| | - Svetlana E Sedelnikova
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, South Yorkshire, UK
| | - Jason S Wilson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, South Yorkshire, UK
| | - John B Rafferty
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, South Yorkshire, UK
| | - Patrick J Baker
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, South Yorkshire, UK.
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Bacillus cereus Induces Severe Infections in Preterm Neonates: Implication at the Hospital and Human Milk Bank Level. Toxins (Basel) 2021; 13:toxins13020123. [PMID: 33562185 PMCID: PMC7915446 DOI: 10.3390/toxins13020123] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/18/2021] [Accepted: 02/02/2021] [Indexed: 12/15/2022] Open
Abstract
Human breast milk (HBM) is a source of essential nutrients for infants and is particularly recommended for preterm neonates when their own mother’s milk is not available. It provides protection against infections and decreases necrotizing enterocolitis and cardiovascular diseases. Nevertheless, HBM spoilage can occur due to contamination by pathogens, and the risk of a shortage of HBM is very often present. B. cereus is the most frequent ubiquitous bacteria responsible for HBM being discarded. It can contaminate HBM at all stages, from its collect point to the storage and delivery. B. cereus can induce severe infection in newborns with very low birth weight, with sometimes fatal outcomes. Although the source of contamination is rarely identified, in some cases, HBM was suspected as a potential source. Even if the risk is low, as infection due to B. cereus in preterm infants should not be overlooked, human milk banks follow strict procedures to avoid contamination, to accurately identify remaining bacteria following pasteurization and to discard non-compliant milk samples. In this review, we present a literature overview of B. cereus infections reported in neonates and the suspected sources of contamination. We highlight the procedures followed by the human milk banks from the collection of the milk to its microbiological characterization in Europe. We also present improved detection and decontamination methods that might help to decrease the risk and to preserve the public’s confidence in this vital biological product for infants whose mothers cannot breastfeed.
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The Food Poisoning Toxins of Bacillus cereus. Toxins (Basel) 2021; 13:toxins13020098. [PMID: 33525722 PMCID: PMC7911051 DOI: 10.3390/toxins13020098] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/14/2021] [Accepted: 01/25/2021] [Indexed: 12/13/2022] Open
Abstract
Bacillus cereus is a ubiquitous soil bacterium responsible for two types of food-associated gastrointestinal diseases. While the emetic type, a food intoxication, manifests in nausea and vomiting, food infections with enteropathogenic strains cause diarrhea and abdominal pain. Causative toxins are the cyclic dodecadepsipeptide cereulide, and the proteinaceous enterotoxins hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe) and cytotoxin K (CytK), respectively. This review covers the current knowledge on distribution and genetic organization of the toxin genes, as well as mechanisms of enterotoxin gene regulation and toxin secretion. In this context, the exceptionally high variability of toxin production between single strains is highlighted. In addition, the mode of action of the pore-forming enterotoxins and their effect on target cells is described in detail. The main focus of this review are the two tripartite enterotoxin complexes Hbl and Nhe, but the latest findings on cereulide and CytK are also presented, as well as methods for toxin detection, and the contribution of further putative virulence factors to the diarrheal disease.
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Churchill-Angus AM, Sedelnikova SE, Schofield THB, Baker PJ. The A component (SmhA) of a tripartite pore-forming toxin from Serratia marcescens: expression, purification and crystallographic analysis. Acta Crystallogr F Struct Biol Commun 2020; 76:577-582. [PMID: 33263568 PMCID: PMC7716259 DOI: 10.1107/s2053230x20013862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/17/2020] [Indexed: 01/17/2023] Open
Abstract
Tripartite α-pore-forming toxins are constructed of three proteins (A, B and C) and are found in many bacterial pathogens. While structures of the B and C components from Gram-negative bacteria have been described, the structure of the A component of a Gram-negative α-pore-forming toxin has so far proved elusive. SmhA, the A component from the opportunistic human pathogen Serratia marcescens, has been cloned, overexpressed and purified. Crystals were grown of selenomethionine-derivatized protein and anomalous data were collected. Phases were calculated and an initial electron-density map was produced.
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Affiliation(s)
- Alicia M. Churchill-Angus
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Svetlana E. Sedelnikova
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Thomas H. B. Schofield
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Patrick J. Baker
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
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27
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Characteristics of the Protein Complexes and Pores Formed by Bacillus cereus Hemolysin BL. Toxins (Basel) 2020; 12:toxins12110672. [PMID: 33114414 PMCID: PMC7694065 DOI: 10.3390/toxins12110672] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/13/2020] [Accepted: 10/21/2020] [Indexed: 11/25/2022] Open
Abstract
Bacillus cereus Hemolysin BL is a tripartite toxin responsible for a diarrheal type of food poisoning. Open questions remain regarding its mode of action, including the extent to which complex formation prior to cell binding contributes to pore-forming activity, how these complexes are composed, and the properties of the pores formed in the target cell membrane. Distinct complexes of up to 600 kDa were found on native gels, whose structure and size were primarily defined by Hbl B. Hbl L1 and L2 were also identified in these complexes using Western blotting and an LC-MS approach. LC-MS also revealed that many other proteins secreted by B. cereus exist in complexes. Further, a decrease of toxic activity at temperatures ≥60 °C was shown, which was unexpectedly restored at higher temperatures. This could be attributed to a release of Hbl B monomers from tight complexation, resulting in enhanced cell binding. In contrast, Hbl L1 was rather susceptible to heat, while heat treatment of Hbl L2 seemed not to be crucial. Furthermore, Hbl-induced pores had a rather small single-channel conductance of around 200 pS and a probable channel diameter of at least 1 nm on planar lipid bilayers. These were highly instable and had a limited lifetime, and were also slightly cation-selective. Altogether, this study provides astonishing new insights into the complex mechanism of Hbl pore formation, as well as the properties of the pores.
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28
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Schwenk V, Riegg J, Lacroix M, Märtlbauer E, Jessberger N. Enteropathogenic Potential of Bacillus thuringiensis Isolates from Soil, Animals, Food and Biopesticides. Foods 2020; 9:foods9101484. [PMID: 33080854 PMCID: PMC7603059 DOI: 10.3390/foods9101484] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/14/2022] Open
Abstract
Despite its benefits as biological insecticide, Bacillus thuringiensis bears enterotoxins, which can be responsible for a diarrhoeal type of food poisoning. Thus, all 24 isolates from foodstuffs, animals, soil and commercially used biopesticides tested in this study showed the genetic prerequisites necessary to provoke the disease. Moreover, though highly strain-specific, various isolates were able to germinate and also to actively move, which are further requirements for the onset of the disease. Most importantly, all isolates could grow under simulated intestinal conditions and produce significant amounts of enterotoxins. Cytotoxicity assays classified 14 isolates as highly, eight as medium and only two as low toxic. Additionally, growth inhibition by essential oils (EOs) was investigated as preventive measure against putatively enteropathogenic B. thuringiensis. Cinnamon Chinese cassia showed the highest antimicrobial activity, followed by citral, oregano and winter savory. In all tests, high strain-specific variations appeared and must be taken into account when evaluating the hazardous potential of B. thuringiensis and using EOs as antimicrobials. Altogether, the present study shows a non-negligible pathogenic potential of B. thuringiensis, independently from the origin of isolation. Generally, biopesticide strains were indistinguishable from other isolates. Thus, the use of these pesticides might indeed increase the risk for consumers’ health. Until complete information about the safety of the applied strains and formulations is available, consumers or manufacturers might benefit from the antimicrobial activity of EOs to reduce the level of contamination.
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Affiliation(s)
- Valerie Schwenk
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (V.S.); (J.R.); (E.M.)
| | - Janina Riegg
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (V.S.); (J.R.); (E.M.)
| | - Monique Lacroix
- Centre Armand-Frappier Santé Biotechnologie, 531, boul. des Prairies, Laval, QC H7V 1B7, Canada;
| | - Erwin Märtlbauer
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (V.S.); (J.R.); (E.M.)
| | - Nadja Jessberger
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany; (V.S.); (J.R.); (E.M.)
- Correspondence:
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Huang Y, Flint SH, Palmer JS. Bacillus cereus spores and toxins – The potential role of biofilms. Food Microbiol 2020; 90:103493. [DOI: 10.1016/j.fm.2020.103493] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 03/18/2020] [Accepted: 03/20/2020] [Indexed: 01/19/2023]
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30
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Characterization of Bacillus cereus sensu lato isolates from milk for consumption; phylogenetic identity, potential for spoilage and disease. Food Microbiol 2020; 93:103604. [PMID: 32912579 DOI: 10.1016/j.fm.2020.103604] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 06/29/2020] [Accepted: 07/24/2020] [Indexed: 11/21/2022]
Abstract
This study addresses the biodiversity of Bacillus cereus group population present along the value chain of milk for consumption. The B. cereus population did not grow and remained mainly unaltered during storage of milk at 4 °C while storage at a suboptimal temperature at 8 °C (representative of a broken cold chain) caused a major shift in its composition. Mesophilic strains dominated the B. cereus population in raw milk and after storage at 4 °C, while psycrotrophic strains dominated after storage at 8 °C. All psycrotrophic and mesophilic isolates (n = 368) demonstrated high spoilage potentials of the milk components. Fifteen out of 20 mesophilic isolates but only two out of 40 psychrotrophic isolates, exhibited vero cell toxicity. No genes encoding the emetic toxin cereulide were detected in the genomes of 100 milk isolates while 14 of them harbored the enterotoxin genes cytK1/cytK2. Both psycrotrophic and mesophilic isolates carried the enterotoxin genes nheA and hblA. Together, the results provide insight into the composition and properties, of the B. cereus population present in milk along the value chain and during storage at optimal refrigerated temperature and at suboptimal temperature. This knowledge is useful in the dairy industry's work to assure high quality products and for risk assessment.
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Rajkovic A, Jovanovic J, Monteiro S, Decleer M, Andjelkovic M, Foubert A, Beloglazova N, Tsilla V, Sas B, Madder A, De Saeger S, Uyttendaele M. Detection of toxins involved in foodborne diseases caused by Gram‐positive bacteria. Compr Rev Food Sci Food Saf 2020; 19:1605-1657. [DOI: 10.1111/1541-4337.12571] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 04/10/2020] [Accepted: 04/14/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Andreja Rajkovic
- Laboratory of Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience EngineeringGhent University Ghent Belgium
| | - Jelena Jovanovic
- Laboratory of Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience EngineeringGhent University Ghent Belgium
| | - Silvia Monteiro
- Laboratorio Analises, Instituto Superior TecnicoUniversidade de Lisboa Lisbon Portugal
| | - Marlies Decleer
- Laboratory of Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience EngineeringGhent University Ghent Belgium
- Laboratory of Food Analysis, Department of Bioanalysis, Faculty of Pharmaceutical SciencesGhent University Ghent Belgium
| | - Mirjana Andjelkovic
- Operational Directorate Food, Medicines and Consumer SafetyService for Chemical Residues and Contaminants Brussels Belgium
| | - Astrid Foubert
- Laboratory of Food Analysis, Department of Bioanalysis, Faculty of Pharmaceutical SciencesGhent University Ghent Belgium
| | - Natalia Beloglazova
- Laboratory of Food Analysis, Department of Bioanalysis, Faculty of Pharmaceutical SciencesGhent University Ghent Belgium
- Nanotechnology Education and Research CenterSouth Ural State University Chelyabinsk Russia
| | - Varvara Tsilla
- Laboratory of Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience EngineeringGhent University Ghent Belgium
| | - Benedikt Sas
- Laboratory of Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience EngineeringGhent University Ghent Belgium
| | - Annemieke Madder
- Laboratorium for Organic and Biomimetic Chemistry, Department of Organic and Macromolecular ChemistryGhent University Ghent Belgium
| | - Sarah De Saeger
- Laboratory of Food Analysis, Department of Bioanalysis, Faculty of Pharmaceutical SciencesGhent University Ghent Belgium
| | - Mieke Uyttendaele
- Laboratory of Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty of Bioscience EngineeringGhent University Ghent Belgium
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Ramarao N, Tran SL, Marin M, Vidic J. Advanced Methods for Detection of Bacillus cereus and Its Pathogenic Factors. SENSORS (BASEL, SWITZERLAND) 2020; 20:E2667. [PMID: 32392794 PMCID: PMC7273213 DOI: 10.3390/s20092667] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/02/2020] [Accepted: 05/05/2020] [Indexed: 12/21/2022]
Abstract
Bacillus cereus is an opportunistic foodborne pathogen causing food intoxication and infectious diseases. Different toxins and pathogenic factors are responsible for diarrheal syndrome, like nonhemolytic enterotoxin Nhe, hemolytic enterotoxin Hbl, enterotoxin FM and cytotoxin K, while emetic syndrome is caused by the depsipeptide cereulide toxin. The traditional method of B. cereus detection is based on the bacterial culturing onto selective agars and cells enumeration. In addition, molecular and chemical methods are proposed for toxin gene profiling, toxin quantification and strain screening for defined virulence factors. Finally, some advanced biosensors such as phage-based, cell-based, immunosensors and DNA biosensors have been elaborated to enable affordable, sensitive, user-friendly and rapid detection of specific B. cereus strains. This review intends to both illustrate the state of the B. cereus diagnostic field and to highlight additional research that is still at the development level.
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Affiliation(s)
- Nalini Ramarao
- INRAE, AgroParisTech, Micalis Institute, Université Paris-Saclay, 78350 Jouy-en-Josas, France; (S.-L.T.); (M.M.)
| | | | | | - Jasmina Vidic
- INRAE, AgroParisTech, Micalis Institute, Université Paris-Saclay, 78350 Jouy-en-Josas, France; (S.-L.T.); (M.M.)
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33
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Mazzantini D, Fonnesu R, Celandroni F, Calvigioni M, Vecchione A, Mrusek D, Bange G, Ghelardi E. GTP-Dependent FlhF Homodimer Supports Secretion of a Hemolysin in Bacillus cereus. Front Microbiol 2020; 11:879. [PMID: 32435240 PMCID: PMC7218170 DOI: 10.3389/fmicb.2020.00879] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/15/2020] [Indexed: 01/09/2023] Open
Abstract
The multidomain (B-NG) protein FlhF, a flagellar biogenesis regulator in several bacteria, is the third paralog of the signal recognition particle (SRP)-GTPases Ffh and FtsY, which are known to drive protein-delivery to the plasma membrane. Previously, we showed that FlhF is required for Bacillus cereus pathogenicity in an insect model of infection, being essential for physiological peritrichous flagellation, for motility, and for the secretion of virulence proteins. Among these proteins, we found that the L2 component of hemolysin BL, one of the most powerful toxins B. cereus produces, was drastically reduced by the FlhF depletion. Herein, we demonstrate that B. cereus FlhF forms GTP-dependent homodimers in vivo since the replacement of residues critical for their GTP-dependent homodimerization alters this ability. The protein directly or indirectly controls flagellation by affecting flagellin-gene transcription and its overproduction leads to a hyperflagellated phenotype. On the other hand, FlhF does not affect the expression of the L2-encoding gene (hblC), but physically binds L2 when in its homodimeric form, recruiting the protein to the plasma membrane for secretion. We additionally show that FlhF overproduction increases L2 secretion and that the FlhF/L2 interaction requires the NG domain of FlhF. Our findings demonstrate the peculiar behavior of B. cereus FlhF, which is required for the correct flagellar pattern and acts as SRP-GTPase in the secretion of a bacterial toxin subunit.
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Affiliation(s)
- Diletta Mazzantini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Rossella Fonnesu
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Francesco Celandroni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Marco Calvigioni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Alessandra Vecchione
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Devid Mrusek
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Philipps University, Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Philipps University, Marburg, Germany
| | - Emilia Ghelardi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
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Abstract
The Bacillus cereus group includes several Bacillus species with closely related phylogeny. The most well-studied members of the group, B. anthracis, B. cereus, and B. thuringiensis, are known for their pathogenic potential. Here, we present the historical rationale for speciation and discuss shared and unique features of these bacteria. Aspects of cell morphology and physiology, and genome sequence similarity and gene synteny support close evolutionary relationships for these three species. For many strains, distinct differences in virulence factor synthesis provide facile means for species assignment. B. anthracis is the causative agent of anthrax. Some B. cereus strains are commonly recognized as food poisoning agents, but strains can also cause localized wound and eye infections as well as systemic disease. Certain B. thuringiensis strains are entomopathogens and have been commercialized for use as biopesticides, while some strains have been reported to cause infection in immunocompromised individuals. In this article we compare and contrast B. anthracis, B. cereus, and B. thuringiensis, including ecology, cell structure and development, virulence attributes, gene regulation and genetic exchange systems, and experimental models of disease.
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35
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Rana N, Panda AK, Pathak N, Gupta T, Thakur SD. Bacillus cereus: public health burden associated with ready-to-eat foods in Himachal Pradesh, India. Journal of Food Science and Technology 2020; 57:2293-2302. [PMID: 32431355 DOI: 10.1007/s13197-020-04267-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 12/16/2019] [Accepted: 01/21/2020] [Indexed: 11/24/2022]
Abstract
The study determined incidence, enterotoxigenecity and antimicrobial susceptibility profiles of Bacillus cereus isolated from ready-to-eat (RTE) milk products (n = 80), RTE meat products (n = 40), beverages (n = 40) and water samples (n = 60, from food preparing and serving outlets/restaurants) collected from eight different tourist places of Himachal Pradesh. 11.4% (25/220) samples were contaminated with Bacillus and isolates were identified as B. cereus (76.0%, n = 19), B. alvei (12.0%, n = 3), B. polymyxa (8.0%, n = 2) and B. firmus (4.0%, n = 1) by conventional and molecular methods. B. cereus incidence was highest in cheese based foods (25.0%) followed by vegetable soups (16.7%), khoa based foods (14.0%), milk based beverages (10.5%), paneer based foods (8.6%), cream based foods (8.3%) and water (8.3%) samples. Multiplex polymerase chain reaction detected enterotoxigenic genes only in B. cereus isolates. nhe complex (encoding non-haemolytic enterotoxins, ABC) genes were detected only in B. cereus isolates. 57.6% (11/19), 36.8% (7/19) and 5.3% (1/19) harboured all three (nheA, nheB, nheC), two (nheB, nheC) and one (nheC) nhe gene, respectively. Among hbl complex genes (encoding haemolytic enterotoxins CAD), only hblC (36.8%, 7/19) was detected. Incidence B. cereus cytK (encoding cytotoxin enterotoxin) was 52.6% (10/19). Each B. cereus isolate harboured two or more enterotoxigenic genes. Seven isolates had at least one gene from haemolytic and non-haemolytic complexes along with cytK. High levels (> 50%) of antimicrobial resistance were recorded for penicillin, amoxicillin, ampicillin cefixime and ceftazidine in tested B. cereus isolates. Two isolates were identified as multidrug resistant isolates with resistance to ≥ 3 antibiotic classes.
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Affiliation(s)
- Neha Rana
- 1Department of Veterinary Public Health and Epidemiology, Dr. GC Negi College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh 176062 India
| | - Ashok Kumar Panda
- 1Department of Veterinary Public Health and Epidemiology, Dr. GC Negi College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh 176062 India
| | - Nina Pathak
- 1Department of Veterinary Public Health and Epidemiology, Dr. GC Negi College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh 176062 India
| | - Tania Gupta
- 2Department of Veterinary Microbiology, Dr. GC Negi College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh 176062 India
| | - Sidharath Dev Thakur
- 1Department of Veterinary Public Health and Epidemiology, Dr. GC Negi College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh 176062 India
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Yu S, Yu P, Wang J, Li C, Guo H, Liu C, Kong L, Yu L, Wu S, Lei T, Chen M, Zeng H, Pang R, Zhang Y, Wei X, Zhang J, Wu Q, Ding Y. A Study on Prevalence and Characterization of Bacillus cereus in Ready-to-Eat Foods in China. Front Microbiol 2020; 10:3043. [PMID: 32010099 PMCID: PMC6974471 DOI: 10.3389/fmicb.2019.03043] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/17/2019] [Indexed: 12/24/2022] Open
Abstract
Bacillus cereus is widely distributed in different food products and can cause a variety of symptoms associated with food poisoning. Since ready-to-eat (RTE) foods are not commonly sterilized by heat treatment before consumption, B. cereus contamination may cause severe food safety problems. In this study, we investigated the prevalence of B. cereus in RTE food samples from different regions of China and evaluated the levels of bacterial contamination, antibiotic resistance, virulence gene distribution, and genetic polymorphisms of these isolates. Of the tested retail RTE foods, 35% were positive for B. cereus, with 39 and 83% of the isolated strains harboring the enterotoxin-encoding hblACD and nheABC gene clusters, respectively. The entFM gene was detected in all B. cereus strains. The cytK gene was present in 68% of isolates, but only 7% harbored the emetic toxin-encoding gene cesB. Antimicrobial susceptibility testing revealed that the majority of the isolates were resistant not only to most β-lactam antibiotics, but also to rifamycin. Multilocus sequence typing (MLST) revealed that the 368 isolates belonged to 192 different sequence types (STs) including 93 new STs, the most prevalent of which was ST26. Collectively, our study indicates the prevalence, bacterial contamination levels, and biological characteristics of B. cereus isolated from RTE foods in China and demonstrates the potential hazards of B. cereus in RTE foods.
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Affiliation(s)
- Shubo Yu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Pengfei Yu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,Department of Food Science and Technology, Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
| | - Juan Wang
- College of Food Science, South China Agricultural University, Guangzhou, China
| | - Chun Li
- Department of Food Science and Technology, Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
| | - Hui Guo
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,Department of Food Science and Technology, Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
| | - Chengcheng Liu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,Department of Food Science and Technology, Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
| | - Li Kong
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,Department of Food Science and Technology, Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
| | - Leyi Yu
- Department of Food Science and Technology, Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
| | - Shi Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Tao Lei
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Moutong Chen
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Haiyan Zeng
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Rui Pang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Youxiong Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Xianhu Wei
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Jumei Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yu Ding
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,Department of Food Science and Technology, Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
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Goat Colostrum—Source of Toxigenic Bacillus Cereus. FOLIA VETERINARIA 2019. [DOI: 10.2478/fv-2019-0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
The aim of this study was to evaluate the toxigenic potential of Bacillus cereus strains isolated from frozen goat colostrum. Of the 50 phenotypically suspected B. cereus isolates, 39 (78.0 %) were confirmed as B. cereus by the polymerase chain reaction (PCR) method based on the gyrB gene detection. In these isolates, genes encoding the production of haemolysin BL (Hbl), a complex of non-haemolytic enterotoxins (Nhe) and emetic toxin were detected by the PCR method. In 36 (92.3 %) confirmed B. cereus isolates, genes encoding at least one type of toxins of interest were detected. In all toxigenic isolates, we found the presence of genes for Nhe production, and in 16 (41.0 %) of the isolates, genes encoding both Nhe and haemolysin BL were shown. Eight (20.5 %) of the emetic strains of B. cereus were identified. The emetic toxin production gene was always detected simultaneously with genes encoding non-haemolytic enterotoxin production. The ability to produce BL haemolysin and non-haemolytic enterotoxins were confirmed by the immunochromatographic method. In summary, goat colostrum can be a significant source of toxigenic strains of B. cereus.
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Jessberger N, Kranzler M, Da Riol C, Schwenk V, Buchacher T, Dietrich R, Ehling-Schulz M, Märtlbauer E. Assessing the toxic potential of enteropathogenic Bacillus cereus. Food Microbiol 2019; 84:103276. [PMID: 31421762 DOI: 10.1016/j.fm.2019.103276] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/18/2019] [Accepted: 07/20/2019] [Indexed: 12/17/2022]
Abstract
The diarrheal type of food poisoning caused by enteropathogenic Bacillus cereus has been linked to various exotoxins. Best described are the non-hemolytic enterotoxin (Nhe), hemolysin BL (Hbl), and cytotoxin K (CytK). Due to the ubiquitous prevalence of B. cereus in soil and crops and its ability to form highly resistant endospores, contaminations during food production and processing cannot be completely avoided. Although phylogenetically closely related, enteropathogenic B. cereus strains show a high versatility of their toxic potential. Thus, functional tools for evaluating the pathogenic potential are urgently needed in order to predict hazardous food contaminations. As the diarrheal syndrome is the result of a toxico-infection with enterotoxin production in the intestine, the entire passage of the bacteria within the host, from spore survival in the stomach, spore germination, host cell adherence, and motility, to enterotoxin production under simulated intestinal conditions was compared in a panel of 20 strains, including high pathogenic as well as apathogenic ones. This approach resulted in an overarching virulence analysis scheme. In parallel, we searched for potential toxico-specific secreted markers to discriminate low and high pathogenic strains. To this end, we targeted known exotoxins using an easy to implement immunoblotting approach as well as a caseinolytic exoprotease activity assay. Overall, Nhe component B, sphingomyelinase, and exoproteases showed good correlation with the complex virulence analysis scheme and can serve as a template for future fast and easy risk assessment tools to be implemented in routine diagnostic procedures and HACCP studies.
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Affiliation(s)
- Nadja Jessberger
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany.
| | - Markus Kranzler
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210, Vienna, Austria
| | - Claudia Da Riol
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany
| | - Valerie Schwenk
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany
| | - Tanja Buchacher
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210, Vienna, Austria
| | - Richard Dietrich
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210, Vienna, Austria
| | - Erwin Märtlbauer
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany
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39
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Wilson JS, Churchill-Angus AM, Davies SP, Sedelnikova SE, Tzokov SB, Rafferty JB, Bullough PA, Bisson C, Baker PJ. Identification and structural analysis of the tripartite α-pore forming toxin of Aeromonas hydrophila. Nat Commun 2019; 10:2900. [PMID: 31263098 PMCID: PMC6602965 DOI: 10.1038/s41467-019-10777-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 05/29/2019] [Indexed: 02/07/2023] Open
Abstract
The alpha helical CytolysinA family of pore forming toxins (α-PFT) contains single, two, and three component members. Structures of the single component Eschericia coli ClyA and the two component Yersinia enterolytica YaxAB show both undergo conformational changes from soluble to pore forms, and oligomerization to produce the active pore. Here we identify tripartite α-PFTs in pathogenic Gram negative bacteria, including Aeromonas hydrophila (AhlABC). We show that the AhlABC toxin requires all three components for maximal cell lysis. We present structures of pore components which describe a bi-fold hinge mechanism for soluble to pore transition in AhlB and a contrasting tetrameric assembly employed by soluble AhlC to hide their hydrophobic membrane associated residues. We propose a model of pore assembly where the AhlC tetramer dissociates, binds a single membrane leaflet, recruits AhlB promoting soluble to pore transition, prior to AhlA binding to form the active hydrophilic lined pore. Pore forming toxins (PFTs) form the major group of virulence factors in many pathogenic bacteria. Here the authors identify tripartite α-helical PFTs in pathogenic Gram negative bacteria and structurally characterize AhlABC from Aeromonas hydrophila and propose a model for its pore assembly.
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Affiliation(s)
- Jason S Wilson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK
| | - Alicia M Churchill-Angus
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK
| | - Simon P Davies
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK.,School of Biomedical Sciences, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Svetlana E Sedelnikova
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK
| | - Svetomir B Tzokov
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK
| | - John B Rafferty
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK
| | - Per A Bullough
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK
| | - Claudine Bisson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK.,ISMB, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, WC1E 7HX, UK
| | - Patrick J Baker
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, South Yorkshire, S10 2TN, UK.
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Binding to The Target Cell Surface Is The Crucial Step in Pore Formation of Hemolysin BL from Bacillus cereus. Toxins (Basel) 2019; 11:toxins11050281. [PMID: 31137585 PMCID: PMC6563250 DOI: 10.3390/toxins11050281] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/13/2019] [Accepted: 05/16/2019] [Indexed: 12/19/2022] Open
Abstract
A major virulence factor involved in Bacillus cereus food poisoning is the three-component enterotoxin hemolysin BL. It consists of the binding component B and the two lytic components L1 and L2. Studying its mode of action has been challenging, as natural culture supernatants additionally contain Nhe, the second three-component enterotoxin, and purification of recombinant (r) Hbl components has been difficult. In this study, we report on pore-forming, cytotoxic, cell binding and hemolytic activity of recently generated rHbl components expressed in E. coli. It is known that all three Hbl components are necessary for cytotoxicity and pore formation. Here we show that an excess of rHbl B enhances, while an excess of rHbl L1 hinders, the velocity of pore formation. Most rapid pore formation was observed with ratios L2:L1:B = 1:1:10 and 10:1:10. It was further verified that Hbl activity is due to sequential binding of the components B - L1 - L2. Accordingly, all bioassays proved that binding of Hbl B to the cell surface is the crucial step for pore formation and cytotoxic activity. Binding of Hbl B took place within minutes, while apposition of the following L1 and L2 occurred immediately. Further on, applying toxin components simultaneously, it seemed that Hbl L1 enhanced binding of B to the target cell surface. Overall, these data contribute significantly to the elucidation of the mode of action of Hbl, and suggest that its mechanism of pore formation differs substantially from that of Nhe, although both enterotoxin complexes are sequentially highly related.
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42
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Abdulmawjood A, Herrmann J, Riede S, Jimenez G, Becker A, Breves G. Evaluation of enterotoxin gene expression and enterotoxin production capacity of the probiotic strain Bacillus toyonensis BCT-7112T. PLoS One 2019; 14:e0214536. [PMID: 31022208 PMCID: PMC6483178 DOI: 10.1371/journal.pone.0214536] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 03/14/2019] [Indexed: 12/20/2022] Open
Abstract
The aim of the present study was to evaluate the safety of the probiotic strain Bacillus toyonensis BCT-7112T (active ingredient of Toyocerin) in relation to the enterotoxins haemolysin BL (Hbl) and the non-haemolytic enterotoxin (Nhe) by performing a quantitative reverse transcription (RT) real-time polymerase chain reaction (PCR) and a Western blot assay. The expression levels of the enterotoxin genes hblA, hblD, nheA, nheB and nheC, determined by means of RT real-time PCR in B. toyonensis, were lower than those in B. cereus reference strains. No expression of hblC was detected. The Western blot assays of native and 25-fold concentrated supernatants from B. toyonensis, using monoclonal antibodies directed against the Hbl component L1 and the Nhe component NheB, showed weak bands. The NheC component was not detected in the native supernatant, but weakly in the 25-fold concentrated supernatant. According to the results of the present study, the enterotoxin expression and protein levels of B. toyonensis BCT-7112T were absent or clearly lower compared to the B. cereus reference strains. Thus, their ability to form functional enterotoxins can also be considered to be lower or unlikely compared to the B. cereus reference strains. This experimental approach can be implemented when studying the health and safety as well as harmlessness of probiotic microorganisms.
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Affiliation(s)
- Amir Abdulmawjood
- Institute of Food Quality and Food Safety, Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Jens Herrmann
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Susanne Riede
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | | | - Andre Becker
- Institute of Food Quality and Food Safety, Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Gerhard Breves
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
- * E-mail:
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43
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Nguyen AT, Tallent SM. Screening food for Bacillus cereus toxins using whole genome sequencing. Food Microbiol 2019; 78:164-170. [DOI: 10.1016/j.fm.2018.10.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 08/24/2018] [Accepted: 10/21/2018] [Indexed: 11/24/2022]
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44
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Porcine Gastric Mucin Triggers Toxin Production of Enteropathogenic Bacillus cereus. Infect Immun 2019; 87:IAI.00765-18. [PMID: 30745328 DOI: 10.1128/iai.00765-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/21/2019] [Indexed: 02/01/2023] Open
Abstract
Enteropathogenic Bacillus cereus causes foodborne infections due to the production of pore-forming enterotoxins in the intestine. Before that, spores have to be ingested, survive the stomach passage, and germinate. Thus, before reaching epithelial cells, B. cereus comes in contact with the intestinal mucus layer. In the present study, different aspects of this interaction were analyzed. Total RNA sequencing revealed major transcriptional changes of B. cereus strain F837/76 upon incubation with porcine gastric mucin (PGM), comprising genes encoding enterotoxins and further putative virulence factors, as well as proteins involved in adhesion to and degradation of mucin. Indeed, PGM was partially degraded by B. cereus via secreted, EDTA-sensitive proteases. The amount of enterotoxins detectable in culture media supplemented with PGM was also clearly increased. Tests of further strains revealed that enhancement of enterotoxin production upon contact with PGM is broadly distributed among B. cereus strains. Interestingly, evidence was found that PGM can also strain-specifically trigger germination of B. cereus spores and that vegetative cells actively move toward mucin. Overall, our data suggest that B. cereus is well adapted to the host environment due to massive transcriptome changes upon contact with PGM, attributing mucin an important and, thus far, neglected role in pathogenesis.
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45
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Bräuning B, Groll M. Structural and Mechanistic Features of ClyA-Like α-Pore-Forming Toxins. Toxins (Basel) 2018; 10:toxins10090343. [PMID: 30142951 PMCID: PMC6162564 DOI: 10.3390/toxins10090343] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 08/16/2018] [Accepted: 08/22/2018] [Indexed: 11/24/2022] Open
Abstract
Recent technological advances have seen increasing numbers of complex structures from diverse pore-forming toxins (PFT). The ClyA family of α-PFTs comprises a broad variety of assemblies including single-, two- and three-component toxin systems. With crystal structures available for soluble subunits of all major groups in this extended protein family, efforts now focus on obtaining molecular insights into physiological pore formation. This review provides an up-to-date discussion on common and divergent structural and functional traits that distinguish the various ClyA family PFTs. Open questions of this research topic are outlined and discussed.
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Affiliation(s)
- Bastian Bräuning
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
| | - Michael Groll
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
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46
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Riol CD, Dietrich R, Märtlbauer E, Jessberger N. Consumed Foodstuffs Have a Crucial Impact on the Toxic Activity of Enteropathogenic Bacillus cereus. Front Microbiol 2018; 9:1946. [PMID: 30174669 PMCID: PMC6107707 DOI: 10.3389/fmicb.2018.01946] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 07/31/2018] [Indexed: 11/13/2022] Open
Abstract
Enteropathogenic Bacillus cereus cause diarrhea due to the production of enterotoxins in the intestine. To start this process, spores have to be ingested together with contaminated food and survive the stomach passage. In this study, the influence of consumed foodstuffs on spore survival as well as on cytotoxicity toward colon epithelial cells was investigated. Spore survival of 20 enteropathogenic and apathogenic B. cereus strains during simulated stomach passage was highly strain-specific and did not correlate with the toxic potential. Survival of three tested strains was strain-specifically altered by milk products. Whereas milk, a follow-on formula and rice pudding had only little influence, spores seemed to be protected by milk products with high fat content such as whipped cream and mascarpone. Furthermore, tested milk products decreased the toxic activity of three B. cereus strains toward CaCo-2 cells. Investigating the individual components, lactoferrin, a skim milk powder and vitamins C, B5 and A showed the most inhibiting effects. On the other hand, biotin, vitamin B3 and another skim milk powder even enhanced cytotoxicity. Further studies suggested that these inhibiting effects result only partially from inhibiting cell binding, but rather from blocking the interaction between the single enterotoxin components.
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Affiliation(s)
- Claudia Da Riol
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Richard Dietrich
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Erwin Märtlbauer
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Nadja Jessberger
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
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47
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Carter L, Chase HR, Gieseker CM, Hasbrouck NR, Stine CB, Khan A, Ewing-Peeples LJ, Tall BD, Gopinath GR. Analysis of enterotoxigenic Bacillus cereus strains from dried foods using whole genome sequencing, multi-locus sequence analysis and toxin gene prevalence and distribution using endpoint PCR analysis. Int J Food Microbiol 2018; 284:31-39. [PMID: 29990637 DOI: 10.1016/j.ijfoodmicro.2018.06.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 06/08/2018] [Accepted: 06/21/2018] [Indexed: 10/28/2022]
Abstract
Bacillus cereus strains were isolated from dried foods, which included international brands of spices from South East Asia, Mexico and India purchased from several retail stores, samples of powdered infant formula (PIF), medicated fish feed and dietary supplements. The genetic diversity of 64 strains from spices and PIF was determined using a multiplex endpoint PCR assay designed to identify hemolysin BL, nonhemolytic enterotoxin, cytotoxin K, and enterotoxin FM toxin genes. Thirteen different B. cereus toxigenic gene patterns or profiles were identified among the strains. Randomly selected B. cereus strains were sequenced and compared with reference Genomic Groups from National Center Biotechnology Information using bioinformatics tools. A comprehensive multi-loci sequence analysis (MLSA) was designed using alleles from 25 known MLST genes specifically tailored for use with whole genome assemblies. A cohort of representative genomes of strains from a few FDA regulated commodities like dry foods and medicated fish feed was used to demonstrate the utility of the 25-MLSA approach for rapid clustering and identification of Genome Groups. The analysis clustered the strains from medicated fish feed, dry foods, and dietary supplements into phylogenetically-related groups. 25-MLSA also pointed to a greater diversity of B. cereus strains from foods and feed than previously recognized. Our integrated approach of toxin gene PCR, and to our knowledge, whole genome sequencing (WGS) based sequence analysis, may be the first of its kind that demonstrates enterotoxigenic potential and genomic diversity in parallel.
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Affiliation(s)
- Laurenda Carter
- U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Applied Research and Safety Assessment, Laurel, MD 20708 USA.
| | - Hannah R Chase
- U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Applied Research and Safety Assessment, Laurel, MD 20708 USA
| | - Charles M Gieseker
- U. S. Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, MD 20708, USA
| | - Nicholas R Hasbrouck
- U. S. Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, MD 20708, USA
| | - Cynthia B Stine
- U. S. Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, MD 20708, USA
| | - Ashraf Khan
- Division of Microbiology, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Laura J Ewing-Peeples
- U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Applied Research and Safety Assessment, Laurel, MD 20708 USA
| | - Ben D Tall
- U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Applied Research and Safety Assessment, Laurel, MD 20708 USA
| | - Gopal R Gopinath
- U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Applied Research and Safety Assessment, Laurel, MD 20708 USA
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48
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Investigation of the diversity and safety of the predominant Bacillus pumilus sensu lato and other Bacillus species involved in the alkaline fermentation of cassava leaves for the production of Ntoba Mbodi. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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49
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Evidence for Complex Formation of the Bacillus cereus Haemolysin BL Components in Solution. Toxins (Basel) 2017; 9:toxins9090288. [PMID: 28926954 PMCID: PMC5618221 DOI: 10.3390/toxins9090288] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/11/2017] [Accepted: 09/12/2017] [Indexed: 02/08/2023] Open
Abstract
Haemolysin BL is an important virulence factor regarding the diarrheal type of food poisoning caused by Bacillus cereus. However, the pathogenic importance of this three-component enterotoxin is difficult to access, as nearly all natural B. cereus culture supernatants additionally contain the highly cytotoxic Nhe, the second three-component toxin involved in the aetiology of B. cereus-induced food-borne diseases. To better address the toxic properties of the Hbl complex, a system for overexpression and purification of functional, cytotoxic, recombinant (r)Hbl components L2, L1 and B from E. coli was established and an nheABC deletion mutant was constructed from B. cereus reference strain F837/76. Furthermore, 35 hybridoma cell lines producing monoclonal antibodies (mAbs) against Hbl L2, L1 and B were generated. While mAbs 1H9 and 1D8 neutralized Hbl toxicity and thus, represent important tools for future investigations of the mode-of-action of Hbl on the target cell surface, mAb 1D7, in contrast, even enhanced Hbl toxicity by supporting the binding of Hbl B to the cell surface. By using the specific mAbs in Dot blots, indirect and hybrid sandwich enzyme immuno assays (EIAs), complex formation between Hbl L1 and B, as well as L1 and L2 in solution could be shown for the first time. Surface plasmon resonance experiments with the rHbl components confirmed these results with KD values of 4.7 × 10−7 M and 1.5 × 10−7 M, respectively. These findings together with the newly created tools lay the foundation for the detailed elucidation of the molecular mode-of-action of the highly complex three-component Hbl toxin.
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50
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Tirloni E, Ghelardi E, Celandroni F, Bernardi C, Casati R, Rosshaug PS, Stella S. Bacillus cereus in fresh ricotta: Comparison of growth and Haemolysin BL production after artificial contamination during production or post processing. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.04.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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