Cereus Isolates Research Articles

Prevalence and antimicrobial-resistant characterization of Bacillus cereus isolated from ready-to-eat rice products in Eastern China.

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.

Genetic diversity of enterotoxigenic Bacillus cereus strains in coriander in southwestern Mexico.

BackgroundCoriander, like other leafy green vegetables, is available all year round and is commonly consumed raw in Mexico as in other countries in the preparation of street or homemade food. Bacillus cereus (B. cereus) is a microorganism that can reach coriander because it is usually found in the soil and in some regions the vegetables are irrigated with polluted water. Therefore, the aim of this study was to determinate the presence of B. cereus in coriander used for human consumption in southwestern Mexico and determine the toxigenic profile, biofilm production, genes associated with the production of biofilms, sporulation rates, enzymatic profile, psychotropic properties, and genetic diversity of B. cereus.MethodsFresh coriander samples were collected from several vegetable retailers in different markets, microbiological analysis was performed. Molecular identification, genes related to the production of biofilm, and toxin gene profiling of B. cereus isolates were determined by PCR. The biofilm formation was measured by performing a crystal violet assay. The genetic diversity of B. cereus strains was determined by PCR of repetitive elements using oligonucleotide (GTG) 5.ResultsWe found a frequency of B. cereus in vegetables was 20% (13/65). In this study, no strains with genes for the HBL toxin were found. In the case of genes related to biofilms, the frequency was low for sipW [5.8%, (1/17)] and tasA [11.7%, (2/17)]. B. cereus strains produce a low amount of biofilm with sporulation rates around 80%. As for genetic diversity, we observed that strains isolated from the same market, but different vegetable retailers are grouped into clusters. In the coriander marketed in southwestern Mexico, were found B. cereus strains with genes associated with the production of diarrheal toxins. Together, these results show actual information about the state of art of B. cereus strains circulating in the southwestern of Mexico.

Characterization of the pathogenicity of a Bacillus cereus isolate from the Mariana Trench

ABSTRACT Bacillus cereus is an important opportunistic pathogen widely distributed in the environment. In this study, we reported the isolation and characterization of a B. cereus isolate, MB1, from the Challenger Deep of the Mariana Trench. MB1 is aerobic, motile, and able to form endospores. It possesses 5966 genes distributed on a circular chromosome and two plasmids. The MB1 genome contains 14 sets of 23S, 5S, and 16S ribosomal RNA operons, 106 tRNA genes, 4 sRNA genes, 12 genomic islands, 13 prophages, and 302 putative virulence genes, including enterotoxins and cytolysins. Infection studies showed that MB1 was able to cause acute and lethal infection in fish and mice, and was highly toxic to mammalian cells. MB1 induced, in a dose-dependent manner, pyroptotic cell death, characterized by activation of caspase-1, cleavage of gasdermin D, and release of IL-1β and IL-18. MB1 spores exhibited swimming and haemolytic capacity, but were severely attenuated in pathogenicity, which, however, was regained to the full extent when the spores germinated under suitable conditions. Taken together, these results provide new insights into the biological and pathogenic mechanism of deep sea B. cereus.

Toxigenic Potential of Mesophilic and Psychrotolerant Bacillus cereus Isolates from Chilled Tofu.

The prevalence, toxin gene profile, antibiogram, and biofilm formation to determine the virulence potential of mesophilic and psychrotolerant Bacillus cereus (B. cereus) isolated from chilled tofu were investigated. Among 58 isolates, 21 isolates were capable of growth at 7 °C, and these isolates shared a potential hazard for food poisoning with mesophilic isolates. B. cereus harboring enterotoxin genes was more frequently found in psychrotolerant isolates than in mesophilic isolates. Thirty-seven (62.2%) mesophilic isolates and all psychrotolerant isolates carried four or more enterotoxin genes. The hemolysin BL (42.9%) and nonhemolytic enterotoxin complexes (90.5%) were found at a higher frequency in psychrotolerant isolates than in mesophilic isolates. Some B. cereus isolates showed resistance to rifampicin or clindamycin, regardless of mesophilic and psychrotolerant isolates. A total of 56% and 40% mesophilic isolates displayed the strongest biofilm formation at 40 and 42 °C, respectively. However, the biofilm formation of psychrotolerant isolates was not significantly affected by temperature. The results of this study provide new strategies for the development of bacterial control, which allows us to optimize technologies to inhibit B. cereus, including psychrotolerant isolates, in the food industry.

Investigation of a cluster of Bacillus cereus bacteremia in neonatal care units.

Bacillus cereus is a well-known pathogen for self-limited foodborne illness, and rarely an opportunistic pathogen associated with invasive infections among immunocompromised patients. Nosocomial outbreaks have been rarely reported. Between August and November 2019, four preterm neonates in neonatal care units of a medical center developed late-onset B. cereus bacteremia. An investigation was carried out. Forty-eight environmental specimens were obtained from these neonatal units, skin surface and environmental objects of Patient 4 for the detection of this organism 19 days after the onset of illness of Patient 4. B. cereus isolates from Patient 4, five unrelated patients and environmental objects if identified were further characterized by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). All four infants survived after vancomycin-containing treatment. Patient 4 developed diffuse cerebritis, brain abscess with severe neurologic sequelae. Of the 48 environmental samplings, 26 specimens showed positive for B. cereus, with one major clone (sequence type 365) accounting for 73%. The isolate from Patient 4 (ST427) was identical to one isolate collected from environmental objects in the same unit. After extensive cleaning of the environment and re-institution of the sterilization procedure of hospital linens, which was ceased since two months before the outbreak, no more cases was identified in these units for at least one year. We documented a cluster of B. cereus bacteremia involving four preterm infants, which might be associated with cessation of the procedure for linen sterilization and was successfully controlled by re-institution of this procedure.

Prevalence of Bacillus cereus in dairy powders focusing on its toxigenic genes and antimicrobial resistance

Bacillus cereus is a common environmental foodborne microorganism that is mainly found to harbor toxigenic genes with multiple antibiotic resistances and is linked to threatening the safety of dried milk in concern to powdered infant milk formula. In the current investigation, the mean value of B. cereus in 140 samples of powdered milk was 0.57 × 102 ± 0.182 × 102, 0.15 × 102 ± 0.027 × 102, 0.21 × 102 ± 0.035 × 102, and 0.32 × 102 ± 0.072 × 102 CFU/g in a percentage of 64.0 samples of whole milk powder, 43.3 of skim milk powder, 26.7 of powdered infant milk formula and 36.7 milk–cereal-based infant formula, respectively. The results revealed that B. cereus isolates were found to harbor toxigenic genes in the following percentages: 77.8, 2.0, 72.7, 16.2, and 67.7 for nhe, hbl, cytK, ces, and bceT, respectively. Despite all evaluated B. cereus strains were originated from dairy powders, they showed a significant difference (P < 0.05) in their harbored toxigenic cytK gene between whole and skim milk powders with powdered infant formula and milk–cereal-based infant formula, as well as between powdered infant formula and milk–cereal-based infant formula. All isolated B. cereus strains were resistant to cefoxitin, colistin sulfate, neomycin, trimethoprim–sulfamethoxazole, oxacillin, and penicillin. Based on the antimicrobial resistance of B. cereus strains to cephalothin, chloramphenicol, nalidixic acid, and tetracycline, there was a significant difference (P < 0.05) between powdered infant milk formula and whole milk powder strains. This survey is one of few studies proceeded in Egypt to determine the prevalence of toxigenic B. cereus strains in milk–cereal-based infant formula and powdered infant formula as well as skim milk powder.

OPTIMIZATION OF THE GROWTH MEDIA OF Bacillus cereus BACTERIA WITH THE ADDITION OF SKIM MILK AND DIFFERENT CARBON SOURCES

The goal of this research was to find the optimal media for growing B. cereus bacteria with various carbon sources. This study used an experimental method with two Bacillus cereus bacterium isolates, namely B. cereus strain SN7 (isolate N) and a consortium of bacteria isolates (a combination of several B. cereus isolates with different strains). The two isolates were grown in sago liquid waste media, tofu liquid waste media, and molasses liquid waste media supplemented with a protein source, skim milk, with three replications in each treatment. Bacterial culture growth was measured every 6 hours for 24 hours using two methods: the TPC method and bacterial cell biomass measurement. According to the results of this study's measurements, molasses waste media was the best modified medium for B.cereus growth. The difference in growth between the B. cereus strain SN7 bacterial isolates and the consortium cultured on molasses media was not significant. The isolates with the largest number of cell growth were B. cereus consortium isolates, with 2,023 x108 CFU/mL in the TPC method and 1,011 g/mL in the biomass measurement method at 24 hours

Determination of In Vitro Synergy of Ampicilin and Chloramphenicol against Multidrug Resistant Bacillus cereus Species

Nowadays, combination therapy has become one of the most effective clinical practices in treating infections due to the emergence of multi-resistant microorganisms. In this study, minimum inhibitory concentrations (MICs) of six selected antibiotics; ampicillin, gentamicin, tetracycline, rifampicin, chloramphenicol, and ciprofloxacin were screened towards five Bacillus cereus isolates; KS2, E2, F2, F6, and K2W2 isolated from aquaculture sources and river in Kukup, Johor, Malaysia. Determination of MICs on tested antibiotics showed that all B. cereus isolates were resistant towards ampicillin and rifampicin but most sensitive to chloramphenicol, ciprofloxacin, and gentamicin. Apart from that, this investigation also provides the synergistic effect of ampicillin and chloramphenicol against the B. cereus isolates. On contrary, K2W2 resulted as an antagonism while F6 resulted as indifference. In particular, synergy or double therapy of antibiotics may be required to treat multi-resistant organisms. Furthermore, the observed synergy between ampicillin and chloramphenicol opens a new window of using bacteriocins and antibiotics in combination therapy of infections.

Newly Emerging MDR B. cereus in Mugil seheli as the First Report Commonly Harbor nhe, hbl, cytK, and pc-plc Virulence Genes and bla1, bla2, tetA, and ermA Resistance Genes.

BackgroundBacillus cereus is a common food poisoning pathogen in humans. This study aimed to investigate the prevalence, molecular typing, antibiogram profile, pathogenicity, dissemination of virulence and antibiotic resistance genes associated with natural B. cereus infection among Mugil seheli.MethodsConsequently, 120 M. seheli (40 healthy and 80 diseased) were obtained from private fish farms in Port-said Governorate, Egypt. Afterward, samples were processed for clinical, post-mortem, and bacteriological examinations. The recovered isolates were tested for antimicrobial susceptibility, phenotypic assessment of virulence factors, pathogeneicity, and PCR-based detection of virulence and antibiotic resistance genes.ResultsB. cereus was isolated from 30 (25%) examined fish; the highest prevalence was noticed in the liver (50%). The phylogenetic and sequence analyses of the gyrB gene revealed that the tested B. cereus isolate displayed a high genetic similarity with other B. cereus strains from different origins. All the recovered B. cereus isolates (n =60, 100%) exhibited β-hemolytic and lecithinase activities, while 90% (54/60) of the tested isolates were biofilm producers. Using PCR, the tested B. cereus isolates harbor nhe, hbl, cytK, pc-plc, and ces virulence genes with prevalence rates of 91.6%, 86.6%, 83.4%, 50%, and 33.4%, respectively. Moreover, 40% (24/60) of the tested B. cereus isolates were multidrug-resistant (MDR) to six antimicrobial classes and carried the bla1, bla2, tetA, and ermA genes. The experimentally infected fish with B. cereus showed variable mortality in direct proportion to the inoculated doses.ConclusionAs far as we know, this is the first report that emphasized the existence of MDR B. cereus in M. seheli that reflects a threat to the public health and the aquaculture sector. Newly emerging MDR B. cereus in M. seheli commonly carried virulence genes nhe, hbl, cytK, and pc-plc, as well as resistance genes bla1, bla2, tetA, and ermA.

Profiling of Bacillus cereus enterotoxigenic genes from retailed foods and detection of the nhe and hbl toxins with immunological assay

Bacillus cereus produces pore-forming toxins responsible for diarrhoea; therefore, rapidly detecting these toxins in food retailed for consumption is needed. The genomic DNA of 100 B. cereus isolates recovered from some retailed foods was extracted and used as a template for enterotoxin detection. The detection of genes of non-haemolyticnonhemolytic enterotoxin (nheA, nheB, nheC), hemolysin BL (hblA, hblC, hblD), entFM, cytK and bceT by the isolates was carried out with PCR using primers specific for the targeted genes, while the production of Nhe and Hbl enterotoxins in fifty of the randomly chosen isolates was detected with a Duopath Cereus Enterotoxin kit. Ninety-five percent of the isolates carried one or more components of the NHE complex, while 56% had one or more components of HBL. Sixteen out of the 100 isolates carried all the genes for NHE and HBL complex genes. The entFM, cytK and bceT genes were detected in 85%, 74% and 60% of B. cereus isolates, respectively. Starchy foods had the highest incidence of the HBL complex, while nheA and nheC occurred mostly in protein foods with 90% and 87% incidence, respectively. The immunological kit was able to detect the production of nonhemolytic enterotoxin (Nhe) in all the B. cereus isolates, while 28 B. cereus isolates produced hemolysin (hbl). Nineteen isolates that carried one or more genes encoding hbl did not produce the toxin. This study clearly showed that retailed foods sold in Ogun State, Nigeria, harbor B. cereus enterotoxigenic genes responsible for diarrhoea. These toxins can be rapidly detected in foods using both molecular and immunological methods.

Aerobic spore-forming bacteria in powdered infant formula: Enumeration, identification by MALDI-TOF mass spectrometry (MS), presence of toxin genes and rpoB gene typing

This study aimed to assess the counts and biodiversity characterization of aerobic sporeforming bacteria (ASB) in powdered infant formula (PIF). Fifty-four (n = 54) samples of PIF of three brands were analyzed for mesophilic aerobic bacteria, and ASB counts. ASB isolated from PIF were assessed for their ability to produce spoilage enzymes and hemolytic activity and further identified by MALDI-TOF mass spectrometry. Then, the isolates were subjected to rpoB gene typing and assessment of bceT, entFM, nhe (A, B, C), and hbl (A, B, C) toxin genes. The main species isolated were B. licheniformis (54%), followed by B. cereus (33%) and B. subtilis (5%). The ASB counts ranged from 1 to 4 log CFU/g, and the mean was 2.9 log CFU/g for mesophilic aerobic sporeforming bacteria (MSC) and 2.5 log CFU/g for thermophilic aerobic sporeforming bacteria (TSC). Most PIF samples presented MSC and TSC counts between 2 and 3 log CFU/g. A total of 13%, 50%, and 37% of the samples presented MSC counts from <2 log CFU/g, between 2 and 3 log CFU/g and between 3 and 4 log CFU/g, respectively. Among the ASB isolates, 97% had protease, 84% hydrolyzed starch, 66% had hemolytic activity, and 61% had lecithinase activity. A total of 44 out of 120 isolates harbored at least one toxin gene; 56% for B. cereus, 34% for B licheniformis, and less than 5% for B. subtilis, B pumilus, and L. sphaericus. All B. cereus isolates harbored the nhe gene, 60% entFM, 44% cytK, 32% bceT, and 28% hbl genes. Besides, 17% of B. licheniformis harbored nhe. A small proportion of B. subtilis, B. pumilus, and L. sphaericus carried toxin genes. The rpoB based phylogenetic tree provided high resolution among Bacillus species. The findings of this study provide insights into the phenotypic and genotypic biodiversity of Bacillus present in PIF.

Incidence, toxin gene profile, antibiotic resistance and antibacterial activity of Allium parvum and Allium cepa extracts on Bacillus cereus isolated from fermented millet-based food

Bacillus cereus is a major food poisoning pathogen that generates spores and biofilms, allowing it to survive in varied food systems. This study revealed the incidence, virulence toxin gene profiling, multi-drug resistance of B. cereus from traditional fermented millet-based porridge foods. The antibacterial activity of onion bulbs (Allium parvum and Allium cepa) against B. cereus isolates was also studied. Of 85 millet-based porridge samples collected from 17 locations, 71 samples (83.5%) were contaminated with B. cereus. Toxin gene profiling study revealed that, 31 B. cereus strains isolated from millet-based porridge samples were reported to have hbl (hblA-35.48%, hblC-51.61% and hblD-45.16%), nhe (nheA-48.38%, nheB-45.16% and nheC-41.93%), cytK-58.06%, entFM-70.96% and ces-6.45%. The antibacterial activity of A. parvum showed a higher range of zone of inhibition (ZOI), 13.66 ± 0.57 mm to 21.00 ± 1.00 mm due to the presence of bioactive compounds identified by FTIR and UPLC-MS/MS. In summary, our study confirmed the detection of B. cereus toxin in fermented millet-based porridge and prospects for its effective control by A. parvum extracts.

Insight into Bacillus cereus Associated with Infant Foods in Beijing.

This study was undertaken to investigate the prevalence, antimicrobial resistance, and virulence gene profiles of Bacillus cereus in different brands of infant formula in Beijing supermarkets. Eighty-eight Bacillus cereus isolates were recovered in sixty-eight infant formulas of five domestic brands and fourteen imported brands. The prevalence rate in domestic and imported samples were 70.6% and 52.9%, respectively. Lower mean prevalence level was found in domestic samples (1.17 MPN/g) compared with the imported samples (3.52 MPN/g). Twenty-four virulence gene profiles were found, and most strains carried at least one virulence gene. The prevalence of nheA, nheB, nheC, cytK, bceT, and entFM in domestic and imported brand samples was similar. The occurrence of enterotoxin genes hblA, hblC, and hblD in domestic samples were 22.2%, 27.8%, and 22.2%, respectively, which was significantly higher than imported samples. Antimicrobial drugs-susceptibility analysis showed that all isolates were susceptible to gentamincin, amikacin, and ciprofloxacin; 38%, 7%, and 2.3% were resistant to rifampin, tetracycline, and chloramphenicol, respectively; and only one isolate was resistant to trimethoprim-sulfamethoxazole. Moreover, the cell numbers of Bacillus cereus in prepared infant formula increased rapidly at room temperature. Thus, monitoring guidelines are needed for accepted levels of Bacillus cereus in infant formula.

Identification of a New Pathogenicity Island Within the Large pAH187_270 Plasmid Involved in Bacillus cereus Virulence.

Objectives Bacillus cereus is responsible for food poisoning and rare but severe clinical infections. The pathogenicity of B. cereus strains varies from harmless to lethal strains. The objective of this study was to characterize three B. cereus isolates isolated from the same patient and identify their virulence potentials.MethodsThree isolates of B. cereus were isolated from various blood samples from a patient who developed sepsis following a central venous catheter infection. The three isolates were compared by WGS, genotyping and SNP analysis. Furthermore, the isolates were compared by phenotypical analysis including bacterial growth, morphology, germination efficacy, toxin production, antibiotic susceptibility and virulence in an insect model of infection.ResultsAccording to WGS and genotyping, the 3 isolates were shown to be identical strains. However, the last recovered strain had lost the mega pAH187_270 plasmid. This last strain showed different phenotypes compared to the first isolated strain, such as germination delay, different antibiotic susceptibility and a decreased virulence capacity towards insects. A 50- kbp region of pAH187_270 plasmid was involved in the virulence potential and could thus be defined as a new pathogenicity island of B. cereus.ConclusionsThese new findings help in the understanding of B. cereus pathogenic potential and complexity and provide further hints into the role of large plasmids in the virulence of B. cereus strains. This may provide tools for a better assessment of the risks associated with B. cereus hospital contamination to improve hygiene procedure and patient health.

Determination of the Antagonistic Effects of Some Rhizospheric Bacteria against Macrophomina phaseolina under In Vitro Conditions

Macrophomina phaseolina (Tassi) Goid. is a fungal pathogen causes charcoal rot disease (Sin: Rhizoctonia bataticola) and is responsible for significant yield losses in many plants. In our study, we aimed to evaluate the antagonistic ability of 39 different bacteria, isolated from the fields of sugar beet in 2019, against the pathogen Macrophomina phaseolina isolated from sugar beet, beans and chickpeas. Approximately 31% of the bacteria showed antibiosis effect against the pathogen. It was determined that the effectiveness level of Lelliottia amnigena, Bacillus atrophaeus, B.pumilus and B. cereus (7 isolates) was moderate to high against Macrophomina phaseolina. Bacillus atrophaeus (PTo15-1a) showed the highest efficacy of 80%, 72.94% and 82.35% against Macrophomina phaseolina of chickpea, bean and sugar beet respectively. Lelliottia amnigena (Pto 14-1b) was moderately effective (57.78%) against the chickpea isolate of the pathogen. It was observed that of the seven Bacillus cereus isolates used in the experiment, three isolates (Pto14-1a, Pto12-1b, Pto17-1b) were highly effective against the chickpea pathogen, two (Pto12-1b, Pto14-2b) against bean pathogen, and one (Pto15-1b) against sugar beet isolate. Results have shown varied level of antagonism by different test bacterial against different Macrophomina phaseolina isolates, while the highest level of antibiosis shown by Bacillus atrophaeus against all pathogenic isolates indicated that it can be a potential future bioagent in managing the disease.

Psychrotrophic properties, toxigenic characteristics, and PFGE profiles of Bacillus cereus isolated from different foods and spices

ABSTRACT: Bacillus cereus is an aerobic and facultatively anaerobic, spore-forming bacterium, and it is found naturally in soil and poses a risk factor for the contamination of food and foodstuffs including cereals, vegetables, spices, ready-to-eat (RTE) foods, meats, milk, and dairy products. This study determined the prevalence of B. cereus in raw poultry meat, raw cow’s milk, cheese, spices, and RTE foods in Hatay province. The study also analysed the psychrotrophic properties, toxigenic characteristics, and pulsed-field gel electrophoresis (PFGE) profiles of the isolates. The levels of contamination with B. cereus determined for cheese, raw milk, RTE foods, spices, and raw poultry meat were 16.6%, 34.2%, 42.8%, 49%, and 55.5%, respectively. B. cereus was isolated from 84 (42%) of the 200 samples analysed and the 84 isolates were verified by PCR analysis targeting the haemolysin gene specific for B. cereus. Of the total isolates, 64 (76.1%) were psychrotrophic. The toxin gene profiling of B. cereus isolates was determined by amplifying the four genes nhe, hbl, cytK, and ces. The nhe and cytK genes were most frequently detected in the isolates, while the hbl and ces genes were not found. In addition, a high genetic relationship between the isolates was detected at a 92% similarity level by PFGE analysis. In conclusion, the occurrence of both psychrotrophic and toxigenic B. cereus strains in this study indicated a potential risk for food spoilage and food poisoning.

Detection and characterization of Bacillus cereus isolated from the dialysis fluid.

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 hemodialysis system, which can be explained by its broad ability to produce a biofilm at 25 °C, its relevant production of virulence factors, such as β-hemolysin, lecithinase and cereulide, and its important resistance pattern to antimicrobial drugs. In conclusion, these new findings expand the understanding that this microorganism should not be neglected and new methods for tracking it should be considered.

Anti-microbial, antioxidant potential of Cassia fistula and study their phytochemical assessments

Cassia fistula (C. fistula) is a flowering plant and a member of Fabaceae family. This study was designed to examine the antibacterial, antioxidant and phytochemical activity of ethanolic extract of C. fistula plant. The microbial inhibitory effect of ethanolic extracts of C. fistula was tested against Gram positive isolates such as Bacillus cereus, Staphylococcus aureus and Gram-negative isolates such as Salmonella typhi, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa using disc diffusion method and well diffusion method. The 25 mg extract of C. fistula leaves (CF-05) showed more zone of inhibition against Salmonella typhi, i.e., (21mm) and in 50 mg extract of CF-13 fruit showed best zone of inhibition against Salmonella typhi, i.e., 17 mm. Qualitative analysis and antioxidant activity at various concentrations was also measured. The phytochemical analysis showed the presence of alkaloids, carbohydrates, fats, tannins, flavonoids, saponins, terpenoids, and sterols. The antioxidant activity in 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity revealed the distinguished antioxidant activity of C. fistula.

Profiling of Bacillus cereus on Canadian grain.

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.

Detection of Bacillus cereus sensu lato Isolates Posing Potential Health Risks in Mexican Chili Powder.

The potential presence of spore-forming bacteria related to the Bacillus cereus group in Mexican chili powder elaborated from Capsicum annuum L. is of commercial and clinical interest, because chili powder is an essential spice in the Mexican diet and in diets around the globe. To facilitate detection and isolation of members of this group of spore-forming bacteria from Mexican chili powder samples, we identified colonies that grew on agar medium selective for Bacillus cereus sensu lato, supplemented with polymyxin B (10 µg/mL) and ampicillin (10 to 100 µg/mL). The presumptive B. cereus (s.l.) isolates were tested using a tRNACys-PCR-based approach and the results identified species related phylogenetically to B. cereus, B. thuringiensis, and B. toyonensis. Their toxigenic potential was assessed by serological tests to detect enterotoxins (Nhe and Hbl) and by PCR targeting the hemolysin BL (hbl) component C (hblC) and non-hemolytic enterotoxin component A (nheA). The antibiotic profiles of the isolates showed a high resistance to β-lactams (100% of the isolates), trimethoprim-sulfamethoxazole (100%), tetracycline (90%), erythromycin (77%), clindamycin (74%), and chloramphenicol (42%). Our results indicate the presence of B. cereus s.l. with toxigenic characteristics in Mexican chili powder. Because of the potential for these organisms to cause disease through their production of various toxins, and resistance to antibiotics, we recommend that a microbiological risk assessment must be considered in the Mexican regulatory requirements.