Incidence, toxin gene profiling, antimicrobial susceptibility, and genetic diversity of Bacillus cereus isolated from quick-frozen food in China

Bacillus cereus is an opportunistic foodborne pathogen causing food intoxication and infectious diseases. Different toxins and pathogenic factors are responsible for diarrheal syndrome, like nonhemolytic enterotoxin Nhe, hemolytic enterotoxin Hbl, enterotoxin FM and cytotoxin K, while emetic syndrome is caused by the depsipeptide cereulide toxin. The traditional method of B. cereus detection is based on the bacterial culturing onto selective agars and cells enumeration. In addition, molecular and chemical methods are proposed for toxin gene profiling, toxin quantification and strain screening for defined virulence factors. Finally, some advanced biosensors such as phage-based, cell-based, immunosensors and DNA biosensors have been elaborated to enable affordable, sensitive, user-friendly and rapid detection of specific B. cereus strains. This review intends to both illustrate the state of the B. cereus diagnostic field and to highlight additional research that is still at the development level.

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Prevalence, Genetic Diversity, and Antibiotic Susceptibility of Bacillus cereus Strains Isolated from Rice and Cereals Collected in Korea

Journal of Food Protection ◽

10.4315/0362-028x-72.3.612 ◽

2009 ◽

Vol 72 (3) ◽

pp. 612-617 ◽

Cited By ~ 69

Author(s):

YONG-BAE PARK ◽

JUNG-BEOM KIM ◽

SANG-WOON SHIN ◽

JONG-CHAN KIM ◽

SEUNG-HAK CHO ◽

...

Keyword(s):

Genetic Diversity ◽

Bacillus Cereus ◽

Antibiotic Susceptibility ◽

Brown Rice ◽

Phenotypic Characterization ◽

Toxin Gene ◽

Glutinous Rice ◽

Job’S Tears ◽

Rice Samples ◽

Toxic Potential

Incidence and properties of Bacillus cereus strains naturally present in cereals were evaluated by phenotypic characterization, antibiotic susceptibility testing, and pulsed-field gel electrophoresis. Of 293 cereal samples tested, 73 (25%) contained B. cereus strains. Incidence of B. cereus isolates varied with respect to sample; they were found in 15 (37%) of 83 brown rice samples, 23 (37%) of 63 glutinous rice samples, 16 (21%) of 76 barley samples, and 19 (27%) of 71 Job's tears samples. All B. cereus isolates from cereals were positive for diarrheal toxin genes. The isolates were susceptible to most of the antibiotics tested, but they were highly resistant to ampicillin, cefepime, oxacillin, and penicillin. Of the genes assayed by the PCR technique, a high frequency of nheA (99%) and hblDC (84%) was found in the genomic DNA of cereal-associated isolates, whereas cytK was less common (55%). From the strains carrying the hblDC genes, 93% produced enterotoxin HBL. B. cereus isolates did not have significant genetic homology. The genetic diversity and toxic potential differ among the strains isolated from cereals. These results provide important information on toxin gene profiles of cereal-associated B. cereus for population studies.

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Further Insights into the Toxicity of Bacillus cytotoxicus Based on Toxin Gene Profiling and Vero Cell Cytotoxicity Assays

Toxins ◽

10.3390/toxins13040234 ◽

2021 ◽

Vol 13 (4) ◽

pp. 234

Author(s):

Johanna Burtscher ◽

Danai Etter ◽

Michael Biggel ◽

Janine Schlaepfer ◽

Sophia Johler

Keyword(s):

Bacillus Cereus ◽

Vero Cell ◽

Diarrheal Disease ◽

Foodborne Pathogen ◽

Food Poisoning ◽

Gene Profiling ◽

Toxin Gene ◽

Cell Cytotoxicity ◽

Cytotoxic Potential ◽

Cytotoxicity Assays

Bacillus cytotoxicus belongs to the Bacillus cereus group that also comprises the foodborne pathogen Bacillus cereus sensu stricto, Bacillus anthracis causing anthrax, as well as the biopesticide Bacillus thuringiensis. The first B. cytotoxicus was isolated in the context of a severe food poisoning outbreak leading to fatal cases of diarrheal disease. Subsequent characterization of the outbreak strain led to the conclusion that this Bacillus strain was highly cytotoxic and eventually resulted in the description of a novel species, whose name reflects the observed toxicity: B. cytotoxicus. However, only a few isolates of this species have been characterized with regard to their cytotoxic potential and the role of B. cytotoxicus as a causative agent of food poisoning remains largely unclear. Hence, the aim of this study was to gain further insights into the toxicity of B. cytotoxicus. To this end, 19 isolates were obtained from mashed potato powders and characterized by toxin gene profiling and Vero cell cytotoxicity assays. All isolates harbored the cytK1 (cytotoxin K1) gene and species-specific variants of the nhe (non-hemolytic enterotoxin) gene. The isolates exhibited low or no toxicity towards Vero cells. Thus, this study indicates that the cytotoxic potential of B. cytotoxicus may be potentially lower than initially assumed.

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Toxin gene profiling of enterotoxic and emetic Bacillus cereus

FEMS Microbiology Letters ◽

10.1111/j.1574-6968.2006.00320.x ◽

2006 ◽

Vol 260 (2) ◽

pp. 232-240 ◽

Cited By ~ 107

Author(s):

Monika Ehling-Schulz ◽

Marie-HÃ©lÃ¨ne Guinebretiere ◽

Amanda MonthÃ¡n ◽

Odile Berge ◽

Martina Fricker ◽

...

Keyword(s):

Bacillus Cereus ◽

Gene Profiling ◽

Toxin Gene

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

Ciência Rural ◽

10.1590/0103-8478cr20210166 ◽

2022 ◽

Vol 52 (4) ◽

Author(s):

Hayriye Yeşim Can ◽

Mehmet Elmalı ◽

Alper Karagöz ◽

Hüseyin Burak Dişli

Keyword(s):

Bacillus Cereus ◽

Food Poisoning ◽

Raw Milk ◽

Gene Profiling ◽

Poultry Meat ◽

Pcr Analysis ◽

Toxin Gene ◽

Raw Poultry ◽

Pfge Profiles ◽

Milk And Dairy Products

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.

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MOLECULAR DETECTION OF ENTEROTOXIN ( CYT K ) GENE AND ANTIMICROBIAL SUSCEPTIBILITY OF BACILLUS CEREUS ISOLATES FROM MILK AND MILK PRODUCTS

Basrah Journal of veterinary Research ◽

10.33762/bvetr.2012.54771 ◽

2012 ◽

Vol 11 (1) ◽

pp. 164-173 ◽

Cited By ~ 1

Author(s):

Mohammed H. Khudor

Keyword(s):

Bacillus Cereus ◽

Antimicrobial Susceptibility ◽

Molecular Detection ◽

Milk Products

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Molecular Characterization of Antimicrobial Resistance and Virulence Genes of Bacterial Pathogens from Bovine and Caprine Mastitis in Northern Lebanon

Microorganisms ◽

10.3390/microorganisms9061148 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1148

Author(s):

Zahie Abboud ◽

Lucia Galuppo ◽

Marco Tolone ◽

Maria Vitale ◽

Roberto Puleio ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Molecular Characterization ◽

Antimicrobial Susceptibility ◽

Meca Gene ◽

Toxin Gene ◽

Pcr Screening ◽

E Coli ◽

Presenting Symptoms ◽

Flight Mass Spectrometry ◽

Streptococcus Uberis

Mastitis is an infectious disease encountered in dairy animals worldwide that is currently a growing concern in Lebanon. This study aimed at investigating the etiology of the main mastitis-causing pathogens in Northern Lebanon, determining their antimicrobial susceptibility profiles, and identifying their antimicrobial resistance (AMR) genes. A total of 101 quarter milk samples were collected from 77 cows and 11 goats presenting symptoms of mastitis on 45 dairy farms. Bacterial identification was carried out through matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibility was tested by disc diffusion and broth microdilution methods. Molecular characterization included polymerase chain reaction (PCR) screening for genes encoding extended-spectrum beta-lactamases (ESBLs) and plasmid-mediated AmpC among Enterobacterales isolates, and virulence factors among Staphylococcus isolates. Escherichia coli isolates were subjected to phylogenetic typing by a quadruplex PCR method. The most frequently identified species were Streptococcus uberis (19.2%), Streptococcus agalactiae (15.1%), E. coli (12.3%), and Staphylococcus aureus (10.96%). Gram-positive bacteria were resistant to macrolides and tetracycline, whereas gram-negative bacteria displayed resistance to ampicillin and tetracycline. Two ESBL genes, blaTEM (83.3%) and blaOXA (16.7%), and one AmpC beta-lactamase gene, blaCMY-II (16.7%), were detected among six E. coli isolates, which mainly belonged to phylogenetic group B1. Among Staphylococcus spp., the mecA gene was present in three isolates. Furthermore, four isolates contained at least one toxin gene, and all S. aureus isolates carried the ica operon. These findings revealed the alarming risk of AMR in the Lebanese dairy chain and the importance of monitoring antimicrobial usage.

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Temporal Variations in Patterns of Clostridioides difficile Strain Diversity and Antibiotic Resistance in Thailand

Antibiotics ◽

10.3390/antibiotics10060714 ◽

2021 ◽

Vol 10 (6) ◽

pp. 714

Author(s):

Supapit Wongkuna ◽

Tavan Janvilisri ◽

Matthew Phanchana ◽

Phurt Harnvoravongchai ◽

Amornrat Aroonnual ◽

...

Keyword(s):

Antibiotic Resistance ◽

Antimicrobial Susceptibility ◽

Reference Strain ◽

Toxin Production ◽

Temporal Variations ◽

Toxin Gene ◽

Data Sets ◽

Clostridioides Difficile ◽

Life Threatening ◽

Susceptibility Profiles

Clostridioides difficile has been recognized as a life-threatening pathogen that causes enteric diseases, including antibiotic-associated diarrhea and pseudomembranous colitis. The severity of C. difficile infection (CDI) correlates with toxin production and antibiotic resistance of C. difficile. In Thailand, the data addressing ribotypes, toxigenic, and antimicrobial susceptibility profiles of this pathogen are scarce and some of these data sets are limited. In this study, two groups of C. difficile isolates in Thailand, including 50 isolates collected from 2006 to 2009 (THA group) and 26 isolates collected from 2010 to 2012 (THB group), were compared for toxin genes and ribotyping profiles. The production of toxins A and B were determined on the basis of toxin gene profiles. In addition, minimum inhibitory concentration of eight antibiotics were examined for all 76 C. difficile isolates. The isolates of the THA group were categorized into 27 A−B+CDT− (54%) and 23 A-B-CDT- (46%), while the THB isolates were classified into five toxigenic profiles, including six A+B+CDT+ (23%), two A+B+CDT− (8%), five A−B+CDT+ (19%), seven A−B+CDT− (27%), and six A−B−CDT− (23%). By visually comparing them to the references, only five ribotypes were identified among THA isolates, while 15 ribotypes were identified within THB isolates. Ribotype 017 was the most common in both groups. Interestingly, 18 unknown ribotyping patterns were identified. Among eight tcdA-positive isolates, three isolates showed significantly greater levels of toxin A than the reference strain. The levels of toxin B in 3 of 47 tcdB-positive isolates were significantly higher than that of the reference strain. Based on the antimicrobial susceptibility test, metronidazole showed potent efficiency against most isolates in both groups. However, high MIC values of cefoxitin (MICs 256 μg/mL) and chloramphenicol (MICs ≥ 64 μg/mL) were observed with most of the isolates. The other five antibiotics exhibited diverse MIC values among two groups of isolates. This work provides evidence of temporal changes in both C. difficile strains and patterns of antimicrobial resistance in Thailand.

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