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Bacillus paranthracis , a Gram-positive conditional pathogen of Bacillus cereus group species, is capable of causing foodborne and waterborne illnesses, leading to intestinal diseases in humans characterized by diarrhoea and vomiting. However, documented cases of B. paranthracis infection outbreaks are rare in the world, and the genomic background of outbreak strains is seldom characterized. This study retrospectively analyzed strains obtained from an outbreak in schools, as well as from water systems in peri-urban areas, China, in 2020. In total, 28 B. cereus group isolates were retrieved, comprising 6 from stool samples and 22 from water samples. Epidemiological and phylogenetic investigations indicated that the B. paranthracis isolate from drinking water as the causative agent of the outbreak. The genomic comparison revealed a high degree of consistency among 8 outbreak-related strains in terms of antimicrobial resistance gene profiles, virulence gene profiles, genomic content, and multilocus sequence typing (MLST). The strains related to the outbreak show highly similar genomic ring diagrams and close phylogenetic relationships. Additionally, this study shed light on the pathogenic potential and complexity of B. cereus group through its diversity in virulence genes and mice infection model. The findings highlight the usefulness of B. paranthracis genomes in understanding genetic diversity within specific environments and in tracing the source of pathogens during outbreak situations, thereby enabling targeted infection control interventions.

Bacillus cereus (B. cereus) is a common cause of foodborne illness. An outbreak of acute gastrointestinal illness occurred at two middle schools in a rural region of Chongqing, China, in 2021. This study aimed to elucidate the outbreak's characteristics, identify risk factors, and determine the source of contamination. A retrospective cohort study and an environmental investigation were conducted. Vomit samples, anal swabs, and food samples were collected and tested by RT-PCR for 18 species of bacteria and viruses, including B. cereus. Positive samples of B. cereus underwent biochemical experiments and bacterial quantification. A total of 198 cases were reported in this outbreak, with an attack rate of 24.63%. The main symptoms were vomiting (100%), bellyache (83.33%), and dizziness (62.63%). The retrospective cohort study showed a significant association between the outbreak and rice noodles provided by a nearby food manufacturer (RR = 39.63, p < 0.001). B. cereus was detected in 20 vomit samples, three anal swabs, and seven rice noodles samples, with a count exceeding 103 CFU/g. These findings strongly suggested that the outbreak was linked to B. cereus-contaminated rice noodles. Enhancing food safety surveillance and promoting health measures among schools and food manufacturers in rural areas is crucial to prevent similar incidents in the future in Chongqing, China., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Emetic Bacillus cereus strains produce a potent cereulide cytotoxin, which can cause acute and fatal cases of food poisoning. We isolated 18 emetic B. cereus strains from a food poisoning event, and from clinical and non-random food surveillance in China and phenotypic characteristics of haemolysis, starch hydrolysis, salicin fermentation, gelatin liquefaction, cytotoxicity, and susceptibility to antibiotics were assessed. All isolates were positive for haemolysis and gelatin liquefaction, and negative for starch hydrolysis and salicin fermentation. Their haemolytic potentials were intermediate to Bacillus anthracis and B. cereus ATCC 14579 (a non-emetic strain). All isolates were cytotoxic to CHO, Hep-2, and Vero cells, and were sensitive to ampicillin. The homogeneous phenotypes of emetic isolates from China are similar to the corresponding traits of European and Japanese isolates that have been characterized, suggesting highly similar phenotypes of emetic B. cereus worldwide., (© 2021 The Society for Applied Microbiology.)

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.

Bacillus cereus is an important food-borne pathogenic bacteria and a putrid microorganism in the dairy industry. Raw and pasteurized buffalo milk play important roles in the dairy market in southwestern China. However, the reports on the prevalence and characterization of B. cereus strains isolated from the above sources are lacking. In this study, 150 raw buffalo milk samples and 300 pasteurized buffalo milk samples were collected from 3 provinces in southwestern China. The genotype, virulence gene distribution, antibiotic resistance, and biofilm-forming ability of isolates were analyzed. Ninety-six B. cereus strains were isolated and identified: 50 isolates (33.3%) from buffalo raw milk and 46 isolates (15.3%) from pasteurized buffalo milk. These strains were classified into 41 sequence types (ST) and 5 groups, of which ST857 was the predominant ST. The detection rates of virulence genes nheABC cluster, hblACD cluster, cytK, bceT, entFM, hlyII, and cesB were 89.6%, 13.5%, 64.6%, 71.9%, 84.4%, 62.5%, and 6.25%, respectively. The antimicrobial susceptibility testing showed that more than 90% of the isolates were susceptible to gentamicin, chloramphenicol, ciprofloxacin, erythromycin, vancomycin, and tetracycline, as well as resistant to ampicillin, cefepime, oxacillin, and rifampin. The results of biomass biofilm evaluation of the isolates on the stainless-steel tube showed that the optical density values at a wavelength of 595 nm of all strains in group I were greater than 1, with the strongest overall biofilm-forming ability among 5 groups, and the overall biofilm-forming ability of group III was the weakest. There was a relationship between the biofilm-forming ability and phylogenetic relationship of B. cereus strains. Taken together, our findings are the first to report the contamination situation and characterization of B. cereus isolated from raw and pasteurized buffalo milk in southwestern China as well as indicate the potential risk posed by this pathogen to dairy industry and public health., (Copyright © 2021 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

This study was conducted to reveal the genotyping, antimicrobial susceptibility, and biofilm formation of Bacillus cereus isolated from powdered food products in China. Five hundred powdered food samples were collected from five provinces in China: 100 samples each of powdered infant formula (PIF), soy milk powder (SMP), lotus root powder (LRP), walnut powder (WP), and rice flour (RF). The genotyping of isolates was analyzed using multilocus sequence typing; meanwhile, antimicrobial susceptibility, and ability of biofilms formation on stainless steel tube of isolates were evaluated. Forty-two B. cereus strains were detected with an overall contamination rate of 8.4%, as well as, the highest B. cereus contamination rate was found in SMP (10%), followed by LRP (9%), WP (9%), RF (8%), and PIF (6%). These isolates were divided into 22 sequence types (STs); among them, ST32 (4/42, 9.5%) was the predominant ST. Phylogenetic relationships showed that the 42 strains of B. cereus were divided into three groups (group I, group II, and group III). Antimicrobial susceptibility testing indicated that all isolates were susceptible to tetracycline, gentamicin, erythromycin, and chloramphenicol, while resistant to ampicillin, cefepime, oxacillin, and rifampin. The analysis of ability of biofilm formation on stainless steel tube showed optical density (OD) 595 value of 66.7% of B. cereus isolates was greater than 1. The OD 595 level of isolates belonging to group III was higher compared with the other two groups, and OD 595 values of B. cereus HB1 and HN5 were greater than 2. These findings improved the understanding of the characteristics of B. cereus isolated from powdered food products in China, and provided a theoretical basis for the prevention and control of B. cereus in food industry.

Background: Bacillus cereus is a foodborne pathogen commonly found in nature and food and can cause food spoilage and health issues. Although the prevalence of B. cereus in foods has been reported worldwide, the extent of contamination in edible fungi, which has become increasingly popular as traditional or functional food, is largely unknown. Here we investigated the prevalence, toxin genes' distribution, antibiotic resistance, and genetic diversity of B. cereus isolated from edible fungi in China., Results: Six hundred and ninety-nine edible fungi samples were collected across China, with 198 (28.3%) samples found to be contaminated by B. cereus, with an average contamination level of 55.4 most probable number (MPN)/g. Two hundred and forty-seven B. cereus strains were isolated from the contaminated samples. Seven enterotoxin genes and one cereulide synthetase gene were detected. The detection frequencies of all enterotoxin genes were ≥ 80%, whereas the positive rate of the cesB gene in B. cereus was 3%. Most isolates were resistant to penicillins, β-lactam/β-lactamase inhibitor combinations, cephems, and ansamycins, but were susceptible to penems, aminoglycosides, macrolides, ketolide, glycopeptides, quinolones, phenylpropanol, tetracyclines, lincosamides, streptogramins, and nitrofurans. Meanwhile, 99.6% of all isolates displayed multiple antimicrobial resistance to three or more classes of antimicrobials. Using genetic diversity analysis, all isolates were defined in 171 sequence types (STs), of which 83 isolates were assigned to 78 new STs., Conclusions: This study provides large-scale insight into the prevalence and potential risk of B. cereus in edible fungi in China. Approximately one-third of the samples were contaminated with B. cereus, and almost all isolates showed multiple antimicrobial resistance. Detection frequencies of all seven enterotoxin genes were equal to or more than 80%. These new findings may indicate a need for proper pre-/post-processing of edible fungi to eliminate B. cereus, thereby preventing the potential risk to public health.

This study was conducted to reveal the prevalence, molecular characterization, and antibiotic susceptibility of Bacillus cereus isolated from dairy products including powdered infant formula, raw milk, pasteurized milk, ultra-high-temperature milk, and cheese. Five hundred samples collected from 5 provinces in China were analyzed in overall experiments. Multilocus sequence typing, distribution of toxin genes, and antibiotic susceptibility of the isolates were analyzed. Fifty-four B. cereus strains were detected; of these, 13 isolates (26%) were from raw milk, 12 isolates (12%) from pasteurized milk, 10 isolates (10%) from cheese, 12 isolates (8%) from ultra-high-temperature milk, and 7 isolates (7%) from powdered infant formula. These isolates were divided into 24 sequence types (ST); among them, ST24, ST26, ST82, ST142, ST377, ST857, and ST1046 were the main dominant ST. The results of detection of toxin genes (hblA, hblC, hblD, nheA, nheB, nheC, cytK, entFM, bceT, hlyII, and cesB) showed that 94.4% isolates carried nheABC genes, whereas only 11.1% of the isolates contained the hblACD gene cluster. In addition, detection rates of cytK, bceT, entFM, hlyII, and cesB genes were 75.9, 77.8, 85.2, 53.7, and 11.1%, respectively. The antibiotic susceptibility test indicated that most of B. cereus isolates were resistant to ampicillin, penicillin, cefepime, cephalothin, and oxacillin, and were susceptible to gentamicin, chloramphenicol, imipenem, tetracycline, ciprofloxacin, trimethoprim-sulfamethoxazole, erythromycin, kanamycin, and cefotetan. Therefore, this study revealed the prevalence and characteristics of B. cereus isolated from dairy products in China, indicating the potential risk and contributing to the effective prevention and control of this pathogen., (Copyright © 2020 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Objectives: Bacillus cereus is associated with a variety of human diseases such as haematological malignancies, tetanus, gas gangrene, food poisoning and pseudomembranous colitis. Our team found and isolated a strain, named B. cereus S66, from radiation-contaminated soil in Xinjiang Uygur Autonomous Region. In this study, the drug resistance and toxicity of B. cereus S66 was systematically studied and analysed., Methods: Genomic DNA of B. cereus S66 was sequenced using an Illumina HiSeq 2000 sequencing system. The generated reads were assembled using SOAPdenovo, and GapCloser was used to fill in the gaps. The draft genome was annotated, and virulence genes and drug resistance genes were identified by comparison with multiclass databases., Results: The genome of B. cereus strain S66 is 5 628 370 bp with a GC content of 34.95% and contains various genes related to toxicity and antimicrobial resistance. The number of toxicity genes identified was 496, some of which are associated with gastrointestinal infection, eye infection and neutrophil-activating protein NapA. Antimicrobial resistance-related genes comprised 3.23% of the total genes and conferred resistance to lincomycin, tetracycline, fosfomycin, aminoglycosides, linezolid, chloramphenicol, rifampicin, macrolides, daunorubicin and mupirocin. Three different β-lactamases were also found in isolate S66., Conclusions: The genome sequence of B. cereus S66 provides a valuable reference to further research on multidrug resistance characteristics and pathogenic system analysis of Bacillus sp. in the clinic., (Copyright © 2019 International Society for Antimicrobial Chemotherapy. Published by Elsevier Ltd. All rights reserved.)

Clostridioides (Clostridium) difficile and Bacillus cereus infections are frequently reported in human individually. However, co-infection of both pathogens in human is extremely rare. In the present study, we reported a case of human enteric disease caused by co-infection of C. difficile and B. cereus in Guizhou, China. The 16S rDNA sequencing result showed that C. difficile GMU1 and B. cereus GMU2 were most related to C. difficile ATCC 9689 and B. cereus ATCC 14579. The toxin genotype of C. difficile GMU1 and B. cereus GMU2 were tcdA + tcdB + tcdC + and bceT + nheA + nheB + nheC + , respectively. Cytotoxicity assay demonstrated that C. difficile GMU1 produced significantly higher toxin B compare to C. difficile 630 stain. In contrast, B. cereus GMU2 has comparable NheA toxin productivity compare to previous report. The antimicrobial susceptibility test showed that the combination of ampicillin and vancomycin was most efficient to inhibit both C. difficile GMU1 and B. cereus GMU2., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A new strain SWH-15 was successfully isolated after initial electrokinetic remediation experiment using the same saline soil sampled from Shengli Oilfield, China. Four methods (morphological and biochemical characteristics, whole-cell fatty acid methyl esters (FAMEs) analysis, 16S rRNA sequence analysis and DNA G + C content and DNA-DNA hybridization analysis) were used to identify the taxonomic status of SWH-15 and confirmed that SWH-15 was a novel species of the Bacillus (B.) cereus group. Then, we assessed the degrading ability of the novel strain SWH-15 to crude oil through a microcosm experiment with four treatments, including control (CK), bioremediation using SWH-15 (Bio), electrokinetic remediation (EK), and combined bioremediation and electrokinetic remediation (Bio + EK). The results showed that the Bio + EK combined remediation treatment was more effective than the CK, Bio, and EK treatments in degrading crude oil contaminants. Bioaugmentation, by addition of the strain SWH-15 had synergistic effect with EK in Bio + EK treatment. Bacterial community analysis showed that electrokinetic remediation alone significantly altered the bacterial community of the saline soil. The addition of the strain SWH-15 alone had a weak effect on the bacterial community. However, the strain SWH-15 boosted the growth of other bacterial species in the metabolic network and weakened the impact of electrical field on the whole bacterial community structure in the Bio + EK treatment.

A microcystin-LR (MC-LR)-degrading bacterium was isolated from Lake Chaohu, a eutrophic freshwater lake containing toxic cyanobacterial blooms. Based on the analysis of 16S rDNA gene sequence and physiobiochemical characteristics, the isolated strain, most likely belongs to the genus Bacillus with the highest sequence similarity value with Bacillus nanhaiencis strain K-W39 (JQ799091.1), was named B. nanhaiencis strain JZ-2013. The strain JZ-2013 could grow on mineral salt medium supplied with MC-LR as sole carbon and nitrogen sources. The optimal temperature and pH for strain JZ-2013 growth and MC-LR biodegradation were 30°C and 8.0, respectively. The MC-LR with the initial concentration of 15 mg/L could be consumed 80 % by strain JZ-2013 within 9 days. The existence of exogenous carbon and nitrogen sources could significantly increase the removal efficiency of MC-LR. The strain JZ-2013 can efficiently removed MC-LR of low concentration in real water sample.

Identification of compositions of the biofilm in a Beijing simulator water distribution system pipe networks by PCR and single strand conformation polymorphism (PCR-SSCP) technique and analysis of its heterotrophic bacterial by heterotrophic plate count (HPC) were performed. Results showed that when the water velocities were same, the count of heterotrophic bacterial on the zinficated steel wall was about five times of the PVC. On the other hand, when the pipe materials were zinficated steel, the count of heterotrophic bacterial in the deadwater pipe wall was about 1/5 of the 0.6 m/s region. The difference of the bacterial count maybe related to the smooth of the water pipe surface and the velocity of flow which affected the attachment of the microorganisms and the quantity of O2 and nourishment, respectively. Same SSCP electrophoresis profiles were observed between samples from different material pipes and water velocities. After sequencing and contrasting with the GenBank, the identity of three bands from the SSCP gel with Bacillus cereus (GenBank AB190077), Peudomonas sp. yged143 (GenBank EF419342) and a unclassified bacteria, Bacterium UASWS0134 (GenBank DQ190347) were 100%, 99% and 94%, respectively. The sameness of the microbial community structure may be induced by the samples which were from the same simulator system and the sampling regions were near and the microorganisms could transform in these regions easily. The observed potential pathogens of Bacillus cereus and Peudomonas sp. should lead to a consideration of the microbiology safety of drinking water.

Aims: To isolate and identify nitrogen-fixing bacilli from the plant rhizospheres in Beijing region of China., Methods and Results: A total of 29 isolates were selectively obtained from the rhizospheres of wheat, maize, ryegrass and willow based on their growth on nitrogen-free medium and their resistance to 100 degrees C for 10 min. Of the 29 isolates, seven had nifH gene determined by PCR amplification. The seven isolates were found to belong to the genera Bacillus and Paenibacillus based on phenotypic characterization, 16S rDNA sequence, G+C content and DNA-DNA hybridization. Isolates T1 and W5 were identified as Bacillus cereus and Bacillus marisflavi respectively. Isolates G1, C4 and C5 were identified as Bacillus megaterium. Isolate G2 was identified as Paenibacillus polymyxa and isolate T7 as Paenibacillus massiliensis., Conclusions: This study suggests that nifH gene could be detected in the both genera Bacillus and Paenibacillus. These degenerate primers for nifH gene fragment used in this study were shown to be useful for identifying nitrogen-fixing bacilli., Significance and Impact of the Study: It is the first demonstration that nitrogen fixation exists in B. marisflavi and P. massiliensis and the first report of the sequences of the nifH gene from B. megaterium and B. cereus. The nitrogen-fixing bacilli obtained in this study will be used in our future research for investigating the mechanisms of nitrogen fixation in bacilli.