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1.
Epidemiol Health ; 45: e2023047, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37080726

RESUMO

OBJECTIVES: On Monday, September 6, 2021, at a kindergarten in Jeju Province, a large number of children vomited and developed food poisoning symptoms, and this necessitated an epidemiological investigation. METHODS: The team surveyed symptoms and food intake history of kindergarten children, teachers, and workers who ate lunch between September 2 (Thursday) and September 6 (Monday), excluding weekends. In addition to rectal swabs, environmental samples from preserved foods, cooking utensils, drinking water, and refrigerator handles were collected. Pulsed field gel electrophoresis (PFGE) for genetic fingerprint analysis was also performed. RESULTS: There were 19 cases among 176 subjects, which indicated an attack rate of 10.8%. The epidemic curve showed a unimodal shape, and the average incubation period was 2.6 hours. While no food was statistically significant in food intake history, the analysis of 35 rectal smear samples detected Bacillus cereus in 7 children, 4 teachers, and 1 cooking staff. Enterotoxins were also detected in 12 samples. Out of 38 environmental samples, B. cereus and enterotoxins were detected in the morning snack cereal, lunch bean sprouts, and afternoon snack steamed potatoes on Monday, September 6th. The result of the PFGE test on 10 isolates of B. cereus showed that there was no genetic homology. CONCLUSIONS: Our results indicated that this outbreak was simultaneously caused by various strains of B. cereus from the environment.


Assuntos
Bacillus cereus , Doenças Transmitidas por Alimentos , Criança , Humanos , Bacillus cereus/isolamento & purificação , Surtos de Doenças , Enterotoxinas/isolamento & purificação , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/epidemiologia , República da Coreia/epidemiologia
2.
Biosens Bioelectron ; 220: 114885, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36410158

RESUMO

Foodborne pathogens have raised significant concerns in human public health. Rapid, high-sensitive, low-cost, and easy-to-use testing methods for food safety are needed. In this study, we developed a finger-actuated microfluidic biosensor (FA-MB) for multiplexed detection of Bacillus cereus and other six common foodborne pathogens based on one-pot CRISPR/Cas12a combined with recombinase aided amplification (RAA). Wells for RAA and CRISPR/Cas12a were isolated to avoid interference, while finger-actuated one-way control valves were incorporated to fulfill the unidirectional flow of RAA products to the CRISPR/Cas12a reaction wells, realizing one-pot RAA-CRISPR/Cas12a assay. The final fluorescent signal was acquired and processed by a smartphone. Under selected experimental conditions, seven pathogenic bacteria could be tested in about 1 h with the limits of detection (LODs) below 500 CFU/mL. Recoveries ranged from 90% to 116% of the spiked samples were readily achieved. The proposed FA-MB is highly integrated and easy-to-use, and could be used for rapid, high-sensitive point of care (POC) testing without the external driving device, suitable for resource-constrained settings.


Assuntos
Técnicas Biossensoriais , Contaminação de Alimentos , Microfluídica , Sistemas CRISPR-Cas/genética , Hidrolases , Recombinases/genética , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Bacillus cereus/isolamento & purificação
3.
Braz. j. biol ; 83: 1-9, 2023. ilus, tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1468915

RESUMO

Many soil microorganisms' i.e., bacteria and fungi produce secondary metabolites called antibiotics. These are used for the treatment of some of the bacterial, fungal and protozoal diseases of humans. There is a need for isolation of a broad spectrum of antibiotics from microorganisms due to the emergence of antibiotic resistance. In the present study two antibiotic producing bacteria Klebsiella pneumoniae and Bacillus cereus were isolated from pharmaceutical and poultry feed industry of Hattar, Haripur Pakistan. Total 10 waste samples were collected from different industries (Marble, Ghee, Soap, Mineral, Steel, Poultry Feed, Pharmaceutical, Qarshi, Cosmetic and Glass). Thirty-three bacterial strains were isolated from industrial wastes of these ten different industries. Fourteen out of thirty-three bacterial strains exhibited antimicrobial activities against at least one of the test microbes considered in this study including Escherchia coli, Staphylococcus aureus and Salmonella typhi. The bacteria were isolated by standard serial dilution spread plate technique. Morphological characterization of the isolates was done by Gram staining. Nine bacterial isolates out of fourteen were initially identified as B. cereus and five as K. pneumoniae through biochemical characterization. The antibacterial activities were tested by well diffusion method. Maximum number of antibiotic producing bacteria were isolated from pharmaceutical and poultry feed industry based on the results of primary screening, the most potential isolates S9, S19, S20, S22 and S23 were selected for secondary screening. The maximum activity against E. coli and S. aureus was recorded by bacterial isolate S19 i.e zones of inhibition of 6.5mm and 9mm while S20 showed 7.5mm and 6mm zones respectively. Molecular identification was carried out on the basis of 16S rRNA sequence [...].


Muitos microrganismos do solo, ou seja, bactérias e fungos produzem metabólitos secundários chamados antibióticos. Eles são usados para tratamento de algumas doenças bacterianas, fúngicas e protozoárias em humanos. Há necessidade de isolamento de um amplo espectro de antibióticos de microrganismos devido ao surgimento de resistência aos antibióticos. No presente estudo, duas bactérias produtoras de antibióticos, Klebsiella pneumoniae e Bacillus cereus, foram isoladas da indústria farmacêutica e de ração avícola de Hattar, Haripur, Paquistão. Um total de 10 amostras de resíduos foi coletado de diferentes indústrias (mármore, ghee, sabão, mineral, aço, ração para aves, farmacêutica, Qarshi, cosmética e vidro). Trinta e três cepas bacterianas foram isoladas de resíduos industriais dessas dez diferentes indústrias. Quatorze das 33 cepas bacterianas exibiram atividades antimicrobianas contra pelo menos um dos micróbios de teste considerados neste estudo, incluindo Escherchia coli, Staphylococcus aureus e Salmonella typhi. As bactérias foram isoladas pela técnica de placa de diluição em série padrão. A caracterização morfológica dos isolados foi feita por coloração de gram. Nove isolados bacterianos de 14 foram inicialmente identificados como B. cereus e cinco como K. pneumoniae por meio de caracterização bioquímica. As atividades antibacterianas foram testadas pelo método de difusão em poço. O número máximo de bactérias produtoras de antibióticos foi isolado da indústria farmacêutica e de ração avícola com base nos resultados da triagem primária, os isolados mais potenciais S9, S19, S20, S22 e S23 foram selecionados para a triagem secundária. A atividade máxima contra E. coli e S. aureus foi registrada pelo isolado bacteriano S19, ou seja, zonas de inibição de 6,5 mm e 9 mm, enquanto S20 mostrou zonas de 7,5 mm e 6 mm, respectivamente. A identificação molecular foi realizada com base na análise da sequência 16S [...].


Assuntos
Antibacterianos/síntese química , Bacillus cereus/isolamento & purificação , Klebsiella/isolamento & purificação , Ração Animal/análise , Resíduos Industriais/análise
4.
Clin Microbiol Infect ; 28(1): 137.e1-137.e8, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34111580

RESUMO

OBJECTIVES: Bacillus cereus is responsible for food poisoning and rare but severe clinical infections. The pathogenicity of strains varies from harmless to lethal strains. However, there are currently no markers, either alone or in combination, to differentiate pathogenic from non-pathogenic strains. The objective of the study was to identify new genetic biomarkers to differentiate non-pathogenic from clinically relevant B. cereus strains. METHODS: A first set of 15 B. cereus strains were compared by RNAseq. A logistic regression model with lasso penalty was applied to define combination of genes whose expression was associated with strain pathogenicity. The identified markers were checked for their presence/absence in a collection of 95 B. cereus strains with varying pathogenic potential (food-borne outbreaks, clinical and non-pathogenic). Receiver operating characteristic area under the curve (AUC) analysis was used to determine the combination of biomarkers, which best differentiate between the "disease" versus "non-disease" groups. RESULTS: Seven genes were identified during the RNAseq analysis with a prediction to differentiate between pathogenic and non-pathogenic strains. The validation of the presence/absence of these genes in a larger collection of strains coupled with AUC prediction showed that a combination of four biomarkers was sufficient to accurately discern clinical strains from harmless strains, with an AUC of 0.955, sensitivity of 0.9 and specificity of 0.86. CONCLUSIONS: These new findings help in the understanding of B. cereus pathogenic potential and complexity and may provide tools for a better assessment of the risks associated with B. cereus contamination to improve patient health and food safety.


Assuntos
Bacillus cereus , Microbiologia de Alimentos , Marcadores Genéticos , Bacillus cereus/genética , Bacillus cereus/isolamento & purificação , Filogenia , RNA-Seq , Virulência
5.
Sci Rep ; 11(1): 22695, 2021 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-34811424

RESUMO

Animal hosts infected and killed by parasitoid fungi become nutrient-rich cadavers for saprophytes. Bacteria adapted to colonization of parasitoid fungi can be selected and can predominate in the cadavers, actions that consequently impact the fitness of the parasitoid fungi. In Taiwan, the zombie fungus, Ophiocordyceps unilateralis sensu lato (Clavicipitaceae: Hypocreales), was found to parasitize eight ant species, with preference for a principal host, Polyrhachis moesta. In this study, ant cadavers grew a fungal stroma that was predominated by Bacillus cereus/thuringiensis. The bacterial diversity in the principal ant host was found to be lower than the bacterial diversity in alternative hosts, a situation that might enhance the impact of B. cereus/thuringiensis on the sympatric fungus. The B. cereus/thuringiensis isolates from fungal stroma displayed higher resistance to a specific naphthoquinone (plumbagin) than sympatric bacteria from the environment. Naphthoquinones are known to be produced by O. unilateralis s. l., and hence the resistance displayed by B. cereus/thuringiensis isolates to these compounds suggests an advantage to B. cereus/thuringiensis to grow in the ant cadaver. Bacteria proliferating in the ant cadaver inevitably compete for resources with the fungus. However, the B. cereus/thuringiensis isolates displayed in vitro capabilities of hemolysis, production of hydrolytic enzymes, and antagonistic effects to co-cultured nematodes and entomopathogenic fungi. Thus, co-infection with B. cereus/thuringiensis offers potential benefits to the zombie fungus in killing the host under favorable conditions for reproduction, digesting the host tissue, and protecting the cadaver from being taken over by other consumers. With these potential benefits, the synergistic effect of B. cereus/thuringiensis on O. unilateralis infection is noteworthy given the competitive relationship of these two organisms sharing the same resource.


Assuntos
Formigas/microbiologia , Bacillus cereus/genética , Bacillus cereus/metabolismo , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Cadáver , Hypocreales/metabolismo , Animais , Formigas/classificação , Bacillus cereus/isolamento & purificação , Bacillus thuringiensis/isolamento & purificação , Biodiversidade , Caenorhabditis elegans/microbiologia , Técnicas de Cocultura , Coinfecção , DNA Bacteriano/genética , Florestas , Especificidade de Hospedeiro , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Filogenia , Especificidade da Espécie , Simpatria , Taiwan
6.
Invest Ophthalmol Vis Sci ; 62(14): 14, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34784411

RESUMO

Purpose: The purpose of this study was to explore the C-X-C chemokines CXCL2 and CXCL10 as potential anti-inflammatory targets for Bacillus endophthalmitis. Methods: Bacillus endophthalmitis was induced in C57BL/6J, CXCL2-/-, and CXCL10-/- mice. At specific times postinfection, eyes were analyzed for Bacillus, retinal function, and inflammation. The efficacies of intravitreal anti-CXCL2 and anti-CXCL10 with or without gatifloxacin in B. cereus endophthalmitis were also assessed using the same techniques. Results: Despite similar Bacillus growth in eyes of C57BL/6J, CXCL2-/-, and CXCL10-/- mice, retinal function retention was greater in eyes of CXCL2-/- and CXCL10-/- mice compared to that of C57BL/6J mice. Neutrophil migration into eyes of CXCL2-/- and CXCL10-/- mice was reduced to a greater degree compared to that of eyes of C57BL/6J mice. Infected CXCL2-/- and CXCL10-/- mouse eyes had significantly less inflammation compared to that of C57BL/6J eyes. Retinal structures in infected eyes of CXCL2-/- mice were preserved for a longer time than in CXCL10-/- eyes. Compared to untreated eyes, there was less inflammation and significant retention of retinal function in eyes treated with anti-CXCL2 and anti-CXCL10 with or without gatifloxacin. Conclusions: For Bacillus endophthalmitis, the absence of CXCL2 or CXCL10 in mice resulted in retained retinal function and less inflammation. The absence of CXCL2 led to a better clinical outcome than the absence of CXCL10. The use of anti-CXCL2 and anti-CXCL10 limited inflammation during B. cereus endophthalmitis. These results highlight the utility of CXCL2 and CXCL10 as potential targets for anti-inflammatory therapy that can be tested in conjunction with antibiotics for improving treating Bacillus endophthalmitis.


Assuntos
Bacillus cereus/crescimento & desenvolvimento , Quimiocina CXCL10/fisiologia , Quimiocina CXCL2/fisiologia , Endoftalmite/fisiopatologia , Infecções Oculares Bacterianas/fisiopatologia , Infecções por Bactérias Gram-Positivas/fisiopatologia , Inflamação/fisiopatologia , Animais , Antibacterianos/uso terapêutico , Anticorpos Monoclonais/farmacologia , Bacillus cereus/isolamento & purificação , Quimiocinas CXC/fisiologia , Contagem de Colônia Microbiana , Modelos Animais de Doenças , Eletrorretinografia , Endoftalmite/tratamento farmacológico , Endoftalmite/microbiologia , Infecções Oculares Bacterianas/tratamento farmacológico , Infecções Oculares Bacterianas/microbiologia , Feminino , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Inflamação/tratamento farmacológico , Inflamação/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/imunologia , Retina/fisiopatologia
7.
PLoS One ; 16(11): e0259209, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34735500

RESUMO

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.


Assuntos
Bacillus cereus/classificação , Linho/microbiologia , Triticum/microbiologia , Sequenciamento Completo do Genoma/métodos , Bacillus cereus/genética , Bacillus cereus/isolamento & purificação , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Canadá , Grão Comestível/microbiologia , Genoma Bacteriano , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia
8.
Diagn Microbiol Infect Dis ; 101(4): 115534, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34601446

RESUMO

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.


Assuntos
Bacillus cereus/patogenicidade , Bacillus thuringiensis/patogenicidade , Bacillus cereus/genética , Bacillus cereus/isolamento & purificação , Bacillus thuringiensis/genética , Bacillus thuringiensis/isolamento & purificação , Toxinas Bacterianas/genética , Pré-Escolar , Evolução Fatal , Feminino , Genoma Bacteriano/genética , Infecções por Bactérias Gram-Positivas/imunologia , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/patologia , Humanos , Hospedeiro Imunocomprometido , Sepse/imunologia , Sepse/microbiologia , Sepse/patologia
9.
Artigo em Inglês | MEDLINE | ID: mdl-34494947

RESUMO

Three Gram-positive bacterial strains, BML-BC004, BML-BC017 and BML-BC059, isolated from blood samples from three inpatients in Japan, were identified as members of Bacillus cereus using matrix-assisted laser desorption ionization time-of-flight MS. The 16S rRNA gene sequences of these three strains were more than 97.1 % similar to 18 type strains belonging to the B. cereus group. Whole-genome comparisons, using average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH), confirmed that the three strains represented three individual distinct species belonging to the B. cereus group. A phylogenetic tree showed that BML-BC004, BML-BC017 and BML-BC059 were located close to B. luti, B. mobilis and B. paramycoides, respectively. Based on these phylogenetic and phenotypic data, including values below the threshold for ANI and dDDH, the three strains should be classified as representing three different novel species of the B. cereus group: Bacillus sanguinis sp. nov., with type strain BML-BC004T (=DSM 111102T=JCM 34122T), Bacillus paramobilis sp. nov., with type strain BML-BC017T (=DSM 111100T=JCM 34124T) and Bacillus hominis sp. nov., with type strain BML-BC059T (=DSM 111101T=JCM 34125T).


Assuntos
Bacillus cereus/classificação , Sangue/microbiologia , Filogenia , Bacillus cereus/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Humanos , Japão , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
10.
Arch Virol ; 166(11): 3183-3188, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34505918

RESUMO

A new Bacillus cereus phage, SWEP1, was isolated from black soil. The host lysis activity of phage SWEP1 has a relatively short latent time (20 min) and a small burst size of 83 PFU. The genome of SWEP1 consists of 162,461 bp with 37.77% G+C content. The phage encodes 278 predicted proteins, 103 of which were assigned functionally. No tRNA genes were found. Comparative genomics analysis indicated that SWEP1 is related to Bacillus phage B4 (86.91% identity, 90% query coverage). Phenotypic and genotypic characterization suggested that SWEP1 is a new member of a new species in the genus Bequatrovirus, family Herelleviridae.


Assuntos
Fagos Bacilares/fisiologia , Bacillus cereus/virologia , Genoma Viral , Fagos Bacilares/genética , Fagos Bacilares/isolamento & purificação , Bacillus cereus/isolamento & purificação , Composição de Bases , Replicação do DNA/genética , Genômica , Genótipo , Microscopia Eletrônica de Transmissão , Filogenia , RNA de Transferência/genética , Microbiologia do Solo , Temperatura
11.
Anal Bioanal Chem ; 413(26): 6661-6669, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34476520

RESUMO

Bacillus cereus is one of the most common foodborne pathogens found in various kinds of staple foods such as rice and wheat. A rapid and accurate detection method for this pathogen is highly desirable for the sustainable production of relevant food products. While several classical and molecular-based detection methods are available for the identification of B. cereus, they suffered one or more limitations such as the requirement for a tedious and time-consuming process, less than ideal specificity, and the lack of portability. Herein, we developed the first paper-based sensing device that exhibits high species specificity with sufficiently low limit of detection for the visual detection of specific DNA sequences of B. cereus. The success is attributed to the strategic planning of fabrication in various dimensions including thorough bioinformatics search for highly specific genes, the use of the pyrrolidinyl peptide nucleic acid (PNA) probe whose selectivity advantage is well documented, and an effective PNA immobilization and DNA-binding visualization method with an internal cross-checking system for validating the results. Testing in rice matrices indicates that the sensor is capable of detecting and distinguishing B. cereus from other bacterial species. Hence, this paper-based sensor has potential to be adopted as a practical means to detect B. cereus in food industries.


Assuntos
Bacillus cereus/isolamento & purificação , Técnicas Biossensoriais/métodos , Microbiologia de Alimentos , Ácidos Nucleicos Peptídicos/química , Pirrolidinas/química , Oryza/microbiologia , Papel
12.
Sci Rep ; 11(1): 12007, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099743

RESUMO

Microbial secondary metabolites from extreme environments like hydrothermal vents are a promising source for industrial applications. In our study the protease gene from Bacillus cereus obtained from shallow marine hydrothermal vents in the East China Sea was cloned, expressed and purified. The protein sequence of 38 kDa protease SLSP-k was retrieved from mass spectrometry and identified as a subtilisin serine proteinase. The novel SLSP-k is a monomeric protein with 38 amino acid signal peptides being active over wide pH (7-11) and temperature (40-80 °C) ranges, with maximal hydrolytic activities at pH 10 and at 50 °C temperature. The hydrolytic activity is stimulated by Ca2+, Co2+, Mn2+, and DTT. It is inhibited by Fe2+, Cd2+, Cu2+, EDTA, and PMSF. The SLSP-k is stable in anionic, non-anionic detergents, and solvents. The ability to degrade keratin in chicken feather and hair indicates that this enzyme is suitable for the degradation of poultry waste without the loss of nutritionally essential amino acids which otherwise are lost in hydrothermal processing. Therefore, the proteinase is efficient in environmental friendly bioconversion of animal waste into fertilizers or value added products such as secondary animal feedstuffs.


Assuntos
Bacillus cereus/enzimologia , Proteínas de Bactérias/metabolismo , Queratinas/metabolismo , Serina Proteases/metabolismo , Subtilisinas/metabolismo , Animais , Organismos Aquáticos , Bacillus cereus/química , Bacillus cereus/isolamento & purificação , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Braquiúros/microbiologia , Galinhas , Clonagem Molecular , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Plumas/química , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Temperatura Alta , Concentração de Íons de Hidrogênio , Fontes Hidrotermais/microbiologia , Modelos Moleculares , Oceano Pacífico , Conformação Proteica , Proteólise , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Serina Proteases/química , Serina Proteases/genética , Serina Proteases/isolamento & purificação , Especificidade por Substrato , Subtilisinas/química , Subtilisinas/genética , Subtilisinas/isolamento & purificação
13.
Food Microbiol ; 98: 103759, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33875199

RESUMO

B. cereus is a human pathogen associated with food poisoning leading to gastrointestinal disorders, as well as local and severe systemic infections. The pathogenic spectrum of B. cereus ranges from strains used as probiotics in humans to lethal highly toxic strains. In this study, we gathered a collection of 100 strains representative of the pathological diversity of B. cereus in humans, and characterized these strains for their cytotoxic potential towards human cells. We analyzed the correlation between cytotoxicity to epithelial and macrophage cells and the combination of 10 genes suspected to play a role during B. cereus virulence. We highlight genetic differences among isolates and studied correlations between genetic signature, cytotoxicity and strain pathological status. We hope that our findings will improve our understanding of the pathogenicity of B. cereus, thereby making it possible to improve both clinical diagnosis and food safety.


Assuntos
Bacillus cereus/patogenicidade , Doenças Transmitidas por Alimentos/microbiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Animais , Bacillus cereus/classificação , Bacillus cereus/genética , Bacillus cereus/isolamento & purificação , Linhagem Celular , Células Epiteliais/microbiologia , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Humanos , Macrófagos/microbiologia , Filogenia , Virulência
14.
Arch Microbiol ; 203(6): 3209-3217, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33830284

RESUMO

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


Assuntos
Bacillus cereus , Variação Genética , Plasmídeos , Animais , Bacillus cereus/genética , Bacillus cereus/isolamento & purificação , Meio Ambiente , Fezes/microbiologia , Microbiologia de Alimentos , Trato Gastrointestinal/microbiologia , Leite/microbiologia , Plasmídeos/genética , Microbiologia da Água
15.
Foodborne Pathog Dis ; 18(5): 306-314, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33769083

RESUMO

Bacillus cereus is a common foodborne pathogen that can cause both gastrointestinal and nongastrointestinal diseases. In this study, we collected 603 meat and meat products from 39 major cities in China. The positive contamination rate of B. cereus in the collected samples was 26.37% (159/603), and the contamination level in 5.03% (8/159) positive samples exceeded 1100 most probable number/g. The detection rates of virulence genes were 89.7% for the nheABC gene group, 37.1% for the hblACD gene cluster, 82.3% for cytK-2, and 2.9% for cesB. Notably, all isolates presented with multiple antibiotic resistance, and 99.43% of isolates were resistant to five classes of antibiotics. In addition, the multilocus sequence typing results indicated that all isolates were rich in genetic diversity. Collectively, we conducted a systematic investigation on the prevalence and characterization of B. cereus in meat and meat products in China, providing crucial information for assessing the risk of B. cereus occurrence in meat and meat products.


Assuntos
Bacillus cereus/isolamento & purificação , Farmacorresistência Bacteriana Múltipla/genética , Microbiologia de Alimentos/estatística & dados numéricos , Produtos da Carne/microbiologia , Carne/microbiologia , Animais , Antibacterianos/farmacologia , Bacillus cereus/genética , China/epidemiologia , Tipagem de Sequências Multilocus , Prevalência , Fatores de Virulência/genética , Fatores de Virulência/isolamento & purificação
16.
Biotechnol Lett ; 43(7): 1349-1355, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33694018

RESUMO

BACKGROUND: All RecJ proteins are known to date only perform exonuclease activity. The present study reports that a novel RecJ protein obtained from Bacillus cereus isolated from marine sediments has both endonuclease and exonuclease activities. METHODS: Analysis of the BcRecJ expression induction in E. coli BL21 revealed that the BcRecJ protein cleaved plasmids and genomic DNA in the host cell, and led to cell death and decreased the DNA content. Further, the BcRecJ protein had the ability to degrade supercoiled plasmid DNA into circular or linear forms in vitro. Meanwhile, the BcRecJ protein loaded with an S-modified guide facilitated plasmid linearization and reduced smear formation. RESULTS: The results suggested that this novel BcRecJ protein was different from any reported RecJs and had a longer C-terminus. Testing the BcRecJ mutants indicated that the endonuclease activity was affected by two residues of BcRecJ (D561, E637) after testing the BcRecJ mutants. CONCLUSION: The discovery of the type of protein is a new breakthrough for the RecJ proteins, which has both endonuclease and exonuclease activities.


Assuntos
Bacillus cereus/enzimologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Escherichia coli/crescimento & desenvolvimento , Exodesoxirribonucleases/genética , Exodesoxirribonucleases/metabolismo , Bacillus cereus/isolamento & purificação , Cromossomos Bacterianos/metabolismo , Clonagem Molecular , Endonucleases/genética , Endonucleases/metabolismo , Escherichia coli/genética , Exonucleases/genética , Exonucleases/metabolismo , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Sedimentos Geológicos/microbiologia , Viabilidade Microbiana , Plasmídeos/metabolismo , Transformação Bacteriana
17.
Pediatr Dev Pathol ; 24(4): 361-365, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33729850

RESUMO

Bacillus cereus is a gram-positive, rod-shaped bacterium that is commonly implicated in foodborne illness but has also become increasingly recognized as a source of serious non-gastrointestinal infections, including sepsis, meningitis, and pneumonia. Non-gastrointestinal B. cereus infections have been identified in children, especially in neonates; however, there are no previously described cases of fetal demise associated with B. cereus placental infection. We present a case of acute chorioamnionitis-related intrauterine fetal demise of twin A at 17 weeks gestation, noted two days after selective termination of twin B. Histological examination revealed numerous gram-positive bacilli in placental tissue, as well as fetal vasculature, in the setting of severe acute necrotizing chorioamnionitis and subchorionitis, intervillous abscesses, acute villitis, and peripheral acute funisitis. Cultures of maternal blood and placental tissue both yielded growth of B. cereus. This case underscores the importance of B. cereus as a human pathogen, and specifically demonstrates its potential as an agent of severe intraamniotic and placental infection with poor outcomes for the fetus.


Assuntos
Bacillus cereus/isolamento & purificação , Corioamnionite/diagnóstico , Morte Fetal/etiologia , Infecções por Bactérias Gram-Positivas/diagnóstico , Placenta/microbiologia , Complicações Infecciosas na Gravidez/diagnóstico , Adulto , Corioamnionite/microbiologia , Corioamnionite/patologia , Feminino , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/patologia , Humanos , Masculino , Placenta/patologia , Gravidez , Complicações Infecciosas na Gravidez/microbiologia , Complicações Infecciosas na Gravidez/patologia , Gravidez de Gêmeos
18.
Toxins (Basel) ; 13(2)2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33578634

RESUMO

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


Assuntos
Bacillus cereus/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Enterotoxinas/genética , Microbiologia de Alimentos , Proteínas Hemolisinas/genética , Manihot/microbiologia , Amido/análise , Bacillus cereus/isolamento & purificação , Bacillus cereus/metabolismo , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Enterotoxinas/metabolismo , Manipulação de Alimentos , Regulação Bacteriana da Expressão Gênica , Genótipo , Proteínas Hemolisinas/metabolismo
19.
Braz J Microbiol ; 52(2): 561-573, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33462720

RESUMO

Polyhydroxyalkanoates (PHAs) are polymers with biodegradable and biocompatible properties accumulated in a wide variety of bacterial strains. In the present study, active sludge, wheat starch wastewater (WSW), and oil wastewater were used for the isolation and screening of PHA-accumulating bacteria. WSW was then implemented as a cheap and economical culture medium for the production of PHAs by the selected isolate. The extracted PHA was characterized, and the capability of produced biopolymer for preparing nanoparticles was evaluated. Based on the results, 96 different bacterial isolates were obtained, of which the strains isolated from WSW demonstrated the highest PHA-accumulation capability. The maximum PHA content of 3.07 g/l (59.50% of dry cell weight) was obtained by strain N6 in 21 h. The selected strain was identified by molecular approaches as Bacillus cereus. Afterward, the physicochemical characterization of an accumulated biopolymer was specified as a PHBV copolymer. Finally, spherical homogenous PHBV nanoparticles with a size of 137 nm were achieved. The PHBV nanoparticles showed a suitable small size and good zeta potential for medical applications. Hence, it can be concluded that isolated wild strain (B. cereus) has the potential exploitation capability for cost-effective PHBV production using the WSW.


Assuntos
Bacillus cereus/metabolismo , Nanopartículas/química , Poliésteres/metabolismo , Triticum/microbiologia , Águas Residuárias/microbiologia , Bacillus cereus/química , Bacillus cereus/genética , Bacillus cereus/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Resíduos Industriais/análise , Poliésteres/química , Poli-Hidroxialcanoatos/biossíntese , Amido/química , Triticum/química , Águas Residuárias/química
20.
Pediatr Infect Dis J ; 40(5): e189-e190, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33480664

RESUMO

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.


Assuntos
Infecções por Bacillaceae/complicações , Bacillus cereus/isolamento & purificação , Fasciite Necrosante/etiologia , Lactente Extremamente Prematuro , Infecções dos Tecidos Moles/etiologia , Evolução Fatal , Humanos , Recém-Nascido , Terapia Intensiva Neonatal , Masculino , Cuidados Paliativos
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