Detection and characterization of Bacillus cereus isolated from the dialysis fluid.
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ABSTRACT:
SUBMITTER: Sturmer FCR
PROVIDER: S-EPMC9673119 | biostudies-literature | 2022
REPOSITORIES: biostudies-literature
Publications
Detection and characterization of Bacillus cereus isolated from the dialysis fluid.
Sturmer Fabiana de Cássia Romanha FCR Moreira Paulo Ricardo PR Cargnelutti Juliana Felipetto JF Lopes Leonardo Quintana Soares LQS Lorenzett Ezequiel E Burgo Thiago Augusto de Lima TAL Santos Roberto Christ Vianna RCV
Revista do Instituto de Medicina Tropical de Sao Paulo 20221114
In this study, B. cereus was detected in dialysis fluids within international parameters (ultrapure - maximum limit of 0.1 CFU/mL for heterotrophic bacteria count) by analyzing the pellet obtained through the centrifugation method. We also investigated the ability of the B. cereus isolate to form a biofilm at different temperatures, the production of virulence factors, and the susceptibility to commercial antimicrobial agents. This study demonstrated a high ability of B. cereus to persist in the ...[more]
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Project description:BackgroundBacillus 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.ResultsSix 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.ConclusionsThis 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.
| S-EPMC7557095 | biostudies-literature
Project description:Bacillus cereus, a ubiquitous environmental microorganism known to cause foodborne illness, was isolated from samples taken from imported baby wipes from two different countries. These strains were characterized using a comprehensive molecular approach involving endpoint PCR, whole genome sequencing (WGS), comparative genomics, and biochemical analyses. A multiplex endpoint PCR assay was used to identify the enterotoxins: hemolysin BL, nonhemolytic enterotoxin, cytotoxin K, and enterotoxin FM toxin genes. Phylogenetically, the strains clustered into two major groups according to sequence type (ST) and singleton. We used the Center for Food Safety and Applied Nutrition (CFSAN) GalaxyTrakr BTyper computational tool to characterize the strains further. As an additional means of characterization, we investigated the possible role of carbohydrate transport systems and their role in nutrient uptake by performing a BLAST analysis of the 40 B. cereus genomes recovered from baby wipes. This study outlines a multifaceted workflow that uses the analysis of enterotoxigenic potential, bioinformatics, genomic diversity, genotype, phenotype, and carbohydrate utilization as a comprehensive strategy to characterize these B. cereus strains isolated from baby wipes and further our understanding of the phylogenetic relatedness of strains associated with baby wipe production facilities that could potentially pose an infection risk to a vulnerable infant population.
| S-EPMC9502454 | biostudies-literature
Project description:Processed cheese is a commercial product characterized by high microbiological stability and extended shelf life obtained through the application of severe heat treatment. However, spore-forming bacteria can survive through thermal processes. Among them, microorganisms belonging to Bacillus genus have been reported. In this study, we examined the microbiological population of the first hours' production of processed cheeses in an Italian dairy plant during two seasons, between June and October 2020. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to identify bacteria colonies, allowing the isolation of Bacillus cereus and Bacillussubtilis strains. These results were further confirmed by amplification and sequencing of 16 rRNA bacterial region. A multi-locus sequence type (MLST) analysis was performed to assess the genetic similarity among a selection of isolates. The fourteen B. cereus strains showed two sequence types: ST-32 was observed in only one strain and the ST-371 in the remaining thirteen isolates. On the contrary, all twenty-one B. subtlis strains, included in the study, showed a new allelic profile for the pycA gene, resulting in a new sequence type: ST-249. For B. cereus strains, analysis of toxin genes was performed. All isolates were positive for nheABC, entFM, and cytK, while hblABCD, bceT, and ces were not detected. Moreover, the biofilm-forming ability of B. cereus and B. subtilis strains was assessed, and all selected isolates proved to be biofilm formers (most of them were stronger producers). Considering the genetical similarity between isolates, jointly with the capacity to produce biofilm, the presence of a recurring Bacillus population could be hypothesized.
| S-EPMC8622485 | biostudies-literature
Project description:Bacillus cereus sensu lato (B. cereus sl) is important spoilage bacteria causing milk structure and flavor changes and is ubiquitous in the environment. This study addresses the biodiversity, toxicity, and proteolytic activity of B. cereus sl from 82 environmental samples and 18 raw bovine milk samples from a dairy farm in the region of Tianjin. In sum, 47 B. cereus sl isolates were characterized through biochemical tests, 16S rRNA gene sequencing, and panC gene analysis. Fourteen sequence types (STs) of B. cereus sl were found in raw bovine milk samples, and five new STs (ST2749, ST2750, ST2751, ST2752, and ST2753) were identified in this study. ST1150 was the dominant ST, associated with fecal, air, drinking water, teat skin, teat cup, and teat dip cup. The results of toxin gene analyses showed that 12.77% and 8.51% of isolates carried hblACD and nheABC operons, respectively. In addition, the detection rate of emetic cesB gene was 21.28%. B. cereus sl demonstrated high spoilage potentials even at 7°C, which has the proteolytic activity of 14.32 ± 1.96 μmol of glycine equivalents per ml. Proteolytic activities were significantly (p < 0.05) decreased after the heat treatment. The residual activity of protease produced at 7°C was significantly higher than that produced at 25°C and 37°C after treatment at 121°C for 10 s and 135°C for 5 s (p < 0.01). Together, the results provide insights into the characteristics of B. cereus sl from farm environment and raw bovine milk and revealed that B. cereus sl contamination should also be monitored in raw milk for ultra-high temperature (UHT) products. This knowledge illustrates that strict cleaning management should be implemented to control B. cereus sl and assure high-quality milk products.
| S-EPMC9514233 | biostudies-literature
Project description:Many strains of Bacillus cereus cause gastrointestinal diseases, and the closely related insect pathogen B. thuringiensis has also been involved in outbreaks of diarrhea. The diarrheal types of diseases are attributed to enterotoxins. Two different enterotoxic protein complexes, hemolysin BL (HBL) and nonhemolytic enterotoxin (NHE), and an enterotoxic protein, enterotoxin T, have been characterized, and the genes have been sequenced. PCR primers for the detection of these genes were deduced and used to detect the genes in 22 B. cereus and 41 B. thuringiensis strains. At least one gene of each of the two protein complexes HBL and NHE was detected in all of the B. thuringiensis strains, while six B. cereus strains were devoid of all three HBL genes, three lacked at least two of the three NHE genes, and one lacked all three. Five different sets of primers were used for detection of the gene (bceT) encoding enterotoxin T. The results obtained with these primer sets indicate that bceT is widely distributed among B. cereus and B. thuringiensis strains and that the gene varies in sequence among different strains. PCR with the two primer sets BCET1-BCET3 and BCET1-BCET4 unambiguously detected the bceT gene, as confirmed by Southern analysis. The occurrence of the genes within the two complexes is significantly associated, while neither the occurrence of the two complexes nor the occurrence of the bceT gene is significantly associated in the 63 strains. We suggest an approach for detection of enterotoxin-encoding genes in B. cereus and B. thuringiensis based on PCR analysis with the six primer sets for the detection of genes in the HBL and NHE operons and with the BCET1, BCET3, and BCET4 primers for the detection of bceT. PCR analysis of the 16S-23S rRNA gene internal transcribed spacer region revealed identical patterns for all strains studied.
| S-EPMC92543 | biostudies-literature
Project description:Anthrax is a worldwide zoonotic disease caused by the spore-forming bacterium Bacillus anthracis. Primarily a disease of herbivores, human infections often result from direct contact with contaminated animal products (cutaneous and inhalational anthrax) or through consumption of infected meat (gastrointestinal anthrax). The genetic near neighbor, Bacillus cereus biovar anthracis (Bcbva), causes an anthrax-like illness in the wildlife and livestock of west and central Africa due to the presence and expression of B. anthracis-specific virulence factors in this background. While Bcbva infections have not been reported in humans, a recent seroprevalence study detected Bcbva antibodies in the rural population around Taï National Park. This work describes the development of new TaqMan multiplex PCRs for the simultaneous detection of B. anthracis and Bcbva. The assays are designed to amplify Ba-1, capB, and lef markers in B. anthracis and genomic island IV (GI4), capB, and lef in Bcbva. Our assays allow for the rapid discrimination of B. anthracis and Bcbva and will provide insights into the molecular epidemiology of these two important pathogens that share an overlapping geographical range in west and central Africa.
| S-EPMC7767396 | biostudies-literature
Project description:IntroductionBacillus cereus is a ubiquitous opportunistic human pathogen that causes food intoxications worldwide. However, the genomic characteristics and pathogenic mechanisms of B. cereus are still unclear.MethodsHere, we isolated and purified nine strains of B. cereus (LY01-LY09) that caused vomiting, diarrhea and other symptoms from four foodborne outbreaks happened in Guizhou Province in southwest China from June to September 2021. After colony observation, Gram staining, microscopic examination and biochemical test, they were identified as B. cereus. The genomic characteristics, phylogenetic relationships and virulence factors of the isolated strains were analyzed at the genome level. Genome sequencing, comparative genomic analysis, secondary metabolite analysis and quantitative PCR were utilized to give a thorough exploration of the strains.ResultsWe obtained the genome maps of LY01-LY09 and found that LY01-LY09 had a complex interspecific relationship with B. anthracis and B. thuringiensis. We also observed a contraction of gene families in LY01-LY09, and the contracted families were mainly associated with prophage, which contributed to the species diversity of B. cereus. The Hsp20 gene family underwent a rapid evolution in LY01-LY09, which facilitated the adaptation of the strains to adverse environmental conditions. Moreover, the LY01-LY09 strains exhibited a higher copy number in the non-ribosomal polypeptide synthetase (NRPS) genes and carried the complete cereulide synthetase (ces) gene cluster sequences. Considering that the NRPS system is a classical regulatory mechanism for emetic toxin synthesis, we hypothesized that LY01-LY09 could synthesize emetic toxins through the regulation of ces gene clusters by the NRPS system.DiscussionThese findings are important for further investigation into the evolutionary relationship between B. cereus and their related species, as well as the underlying mechanisms governing the synthesis and secretion of bacterial toxins.
| S-EPMC10822677 | biostudies-literature
Project description:Bacillus cereus is a major food-borne bacterial pathogen in the world, which can cause diarrhea and emetic syndrome. This study aimed to reveal the quantitative prevalence of B. cereus in ready-to-eat (RTE) rice products in Eastern China and to gain essential information on the characteristics of B. cereus isolates. A total of 91 out of the 1071 samples were positive for B. cereus. The contamination level of B. cereus in 0.5 % of RTE rice product samples outnumbered 103 CFU/g. The number of B. cereus attained 105−106 CFU/g in one sample. The distribution patterns of virulence genes in B. cereus isolates were identified. 84.6% of the B. cereus isolates had at least one enterotoxin or emetic toxin gene. The predominant pattern was XXV. 9.9% of isolates belonged to it and possessed one enterotoxin gene entFM. The occurrence rate of hblACD and nheABC was 36.3% and 47.3%, respectively. Antimicrobial susceptibility tests revealed a high resistance rate toward penicillin, and 23.1% of the isolates were multi-drug resistant. B. cereus isolates were genotyped by using ERIC-PCR. 89 genotypes were determined. The Hunter Gaston Discriminatory Index (HGDI) attained 0.9995. Relationships analysis revealed that Group A B. cereus isolates tended to carry hblA, hblC, hblD, nheA, nheB, and show resistance to penicillin/trimethoprim/sulfamethoxazole. This study was useful for updating the knowledge of the contamination status of B. cereus in RTE rice products in China.
| S-EPMC9344136 | biostudies-literature
Project description:Bacillus cereus isolates have been described harboring Bacillus anthracis toxin genes, most notably B. cereus G9241, and capable of causing severe and fatal pneumonias. This report describes the characterization of a B. cereus isolate, BcFL2013, associated with a naturally occurring cutaneous lesion resembling an anthrax eschar. Similar to G9241, BcFL2013 is positive for the B. anthracis pXO1 toxin genes, has a multi-locus sequence type of 78, and a pagA sequence type of 9. Whole genome sequencing confirms the similarity to G9241. In addition to the chromosome having an average nucleotide identity of 99.98% when compared to G9241, BcFL2013 harbors three plasmids with varying homology to the G9241 plasmids (pBCXO1, pBC210 and pBFH_1). This is also the first report to include serologic testing of patient specimens associated with this type of B. cereus infection which resulted in the detection of anthrax lethal factor toxemia, a quantifiable serum antibody response to protective antigen (PA), and lethal toxin neutralization activity.
| S-EPMC4892579 | biostudies-literature
Project description:Specific amino acids, purine ribonucleosides, or a combination of the two is required for efficient germination of endospores of Bacillus cereus ATCC 14579. A survey including 20 different amino acids showed that l-alanine, l-cysteine, l-threonine, and l-glutamine are capable of initiating the germination of endospores of B. cereus ATCC 14579. In addition, the purine ribonucleosides inosine and adenosine can trigger germination of the spores. Advanced annotation of the B. cereus ATCC 14579 genome revealed the presence of seven putative germination (ger) operons, termed gerG, gerI, gerK, gerL, gerQ, gerR, and gerS. To determine the role of the encoded putative receptors in nutrient-induced germination, disruption mutants were constructed by the insertion of pMUTIN4 into each of the seven operons. Four of the seven mutants were affected in the germination response to amino acids or purine ribonucleosides, whereas no phenotype could be attributed to the mutants with disrupted gerK, gerL, and gerS loci. The strain with a disrupted gerR operon was severely hampered in the ability to germinate: germination occurred in response to l-glutamine but not in the presence of any of the other amino acids tested. The gerG mutant showed significantly reduced l-glutamine-induced germination, which points to a role of this receptor in the l-glutamine germination signaling pathway. gerR, gerI, and gerQ mutants showed reduced germination rates in the presence of inosine, suggesting a role for these operons in ribonucleoside signaling. Efficient germination by the combination of l-glutamine and inosine was shown to involve the gerG and gerI operons, since the germination of mutants lacking either one of these receptors was significantly reduced. Germination triggered by the combination of l-phenylalanine and inosine was lost in the gerI mutant, indicating that both molecules are effective at the GerI receptor.
| S-EPMC1352193 | biostudies-literature