1、菌株名称：蜡状芽孢杆菌 Bacillus cereus
3、其它中心编号：JCM 2152=ATCC14579 =BCRC10603 =BCRC11026 =CCM2010 =CCUG7414 =CECT148 =CECT5050 =CGMCC1.3760 =CIP66.24 =DSM31 =IFO15305 =KCTC3624 =LMG6923 =NBRC15305
4、具体用途：食品检测。
斜面菌种和冻干菌种应在2~8℃保存。
1、培养基编号：（1）营养琼脂培养基（NA）（2）胰蛋白胨大豆琼脂培养基（TSA）（3）LB培养基 以上建议的培养基三选一
2、培养温度：30℃；
3、培养时间：24—48h。
1、冻干首次活化，干粉要全部用完，不能保留，参考“开管说明”用无菌吸管吸取0.3ml~0.5ml的培养液（即以上建议的培养基配方，不加琼脂）或者无菌水，滴入冻干管中，轻轻振荡至其溶解，吸取全部菌悬液，接种在培养基上（建议不超过2支斜面或平板；若接种液体培养基，则试管中液体培养基不超过5ml为宜）；
2、复苏后，微生物菌种应保藏于建议的温度、清洁和干燥的地方，室温放置时间过长会导致菌种衰退。
3、初次使用时请按照本说明书推荐条件进行复活培养，如使用其它类型培养基或培养条件造成菌种不活等损失，泰斯拓生物不负责任。
4、使用者应保证菌种的安全存储和操作，带菌废弃物应高压灭菌处理后丢弃。
Bacillus cereus is a Gram-positive, rod-shaped, facultatively anaerobic, motile, beta-hemolytic, spore-forming bacterium commonly found in soil, food and marine sponges.The specific name, cereus, meaning "waxy" in Latin, refers to the appearance of colonies grown on blood agar. Some strains are harmful to humans and cause foodborne illness, while other strains can be beneficial as probiotics for animals. The bacteria is classically contracted from fried rice dishes that have been sitting at room temperature for hours.B. cereus bacteria are facultative anaerobes, and like other members of the genus Bacillus, can produce protective endospores. Its virulence factors include phospholipase C, cereulide, sphingomyelinase, metalloproteases, and cytotoxin K.
The Bacillus cereus group comprises seven closely related species: B. cereus sensu stricto (referred to herein as B. cereus), B. anthracis, B. thuringiensis, B. mycoides, B. pseudomycoides, and B. cytotoxicus; or as six species in a Bacillus cereus sensu lato: B. weihenstephanensis, B. mycoides, B. pseudomycoides, B. cereus, B. thuringiensis, and B. anthracis.
Like most Bacilli, the most common ecosystem of Bacillus cereus is land. In concert with Arbuscular mycorrhiza (and Rhizobium leguminosarum in clover), they can regenerate heavy metal soil by increasing phosphorus, nitrogen, and potassium content in certain plants.
B. cereus competes with other microorganisms such as Salmonella and Campylobacter in the gut; its presence reduces the numbers of those microorganisms. In food animals such as chickens, rabbitsand pigs, some harmless strains of B. cereus are used as a probiotic feed additive to reduce Salmonella in the animals' intestines and cecum. This improves the animals' growth, as well as food safety for humans who eat them. B. cereus can parasitize codling moth larvae.[citation needed]
B. cereus and other members of Bacillus are not easily killed by alcohol; they have been known to colonize distilled liquors and alcohol-soaked swabs and pads in numbers sufficient to cause infection.
Some strains of B. cereus produce cereins, bacteriocins active against different B. cereus strains or other Gram-positive bacteria.
B. cereus is responsible for a minority of foodborne illnesses (2–5%), causing severe nausea, vomiting, and diarrhea. Bacillus foodborne illnesses occur due to survival of the bacterial endospores when infected food is not, or is inadequately, cooked. Cooking temperatures less than or equal to 100 °C (212 °F) allow some B. cereus spores to survive. This problem is compounded when food is then improperly refrigerated, allowing the endospores to germinate. Cooked foods not meant for either immediate consumption or rapid cooling and refrigeration should be kept at temperatures below 10 °C (50 °F) or above 50 °C (122 °F).Germination and growth generally occur between 10 °C and 50 °C,though some strains can grow at low temperatures, and Bacillus cytotoxicus strains have been shown to grow at temperatures up to 52℃. Bacterial growth results in production of enterotoxins, one of which is highly resistant to heat and acids (pH levels between 2 and 11); ingestion leads to two types of illness: diarrheal and emetic (vomiting) syndrome.
The diarrheal type is associated with a wide range of foods, has an 8-to-16-hour incubation time, and is associated with diarrhea and gastrointestinal pain. Also known as the 'long-incubation' form of B. cereus food poisoning, it might be difficult to differentiate from poisoning caused by Clostridium perfringens.[23] Enterotoxin can be inactivated after heating at 56 °C (133 °F) for 5 minutes, but whether its presence in food causes the symptom is unclear, since it degrades in stomach enzymes; its subsequent production by surviving B. cereus spores within the small intestine may be the cause of illness.
The 'emetic' form is commonly caused by rice cooked for a time and temperature insufficient to kill any spores present, then improperly refrigerated. It can produce a toxin, cereulide, which is not inactivated by later reheating. This form leads to nausea and vomiting 1–5 hours after consumption. Distinguishing from other short-term bacterial foodborne intoxications such as by Staphylococcus aureus can be difficult.[23] Emetic toxin can withstand 121 °C (250 °F) for 90 minutes.
The diarrhetic syndromes observed in patients are thought to stem from the three toxins: hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe), and cytotoxin K (CytK). The nhe/hbl/cytK genes are located on the chromosome of the bacteria. Transcription of these genes is controlled by PlcR. These genes occur in the taxonomically related B. thuringiensis and B. anthracis, as well. These enterotoxins are all produced in the small intestine of the host, thus thwarting digestion by host endogenous enzymes. The Hbl and Nhe toxins are pore-forming toxins closely related to ClyA of E. coli. The proteins exhibit a conformation known as a "beta-barrel" that can insert into cellular membranes due to a hydrophobic exterior, thus creating pores with hydrophilic interiors. The effect is loss of cellular membrane potential and eventually cell death. CytK is a pore-forming protein more related to other hemolysins.[citation needed]
The timing of the toxin production was previously thought to be possibly responsible for the two different courses of disease, but in fact the emetic syndrome is caused by a toxin, cereulide, found only in emetic strains and is not part of the "standard toolbox" of B. cereus. Cereulide is a cyclic polypeptide containing three repeats of four amino acids: d-oxy-Leu—d-Ala—l-oxy-Val—l-Val (similar to valinomycin produced by Streptomyces griseus) produced by nonribosomal peptide synthesis. Cereulide is believed to bind to 5-hydroxytryptamine 3 (5-HT3) serotonin receptors, activating them and leading to increased afferent vagus nerve stimulation.It was shown independently by two research groups to be encoded on multiple plasmids: pCERE01 or pBCE4810. Plasmid pBCE4810 shares homology with the B. anthracis virulence plasmid pXO1, which encodes the anthrax toxin. Periodontal isolates of B. cereus also possess distinct pXO1-like plasmids. Like most of cyclic peptides containing nonproteogenic amino acids, cereulide is resistant to heat, proteolysis, and acid conditions.
B. cereus is also known to cause difficult-to-eradicate chronic skin infections, though less aggressive than necrotizing fasciitis. B. cereus can also cause keratitis.
A case study was published in 2019 of a catheter-related bloodstream infection of B. cereus in a 91-year-old male previously being treated with hemodialysis via PermCath for end-stage renal disease.He presented with chills, tachypnea, and high-grade fever, his white blood cell count and high-sensitivity C-reactive protein (CRP) were significantly elevated, and CT imaging revealed a thoracic aortic aneurysm. He was successfully treated for the aneurysm with intravenous vancomycin, oral fluoroquinolones, and PermCath removal.[citation needed]
While B. cereus vegetative cells are killed during normal cooking, spores are more resistant. Viable spores in food can become vegetative cells in the intestines and produce a range of diarrheal enterotoxins, so elimination of spores is desirable. In wet heat (poaching, simmering, boiling, braising, stewing, pot roasting, steaming), spores require more than 5 minutes at 121 °C (250 °F) at the coldest spot to be destroyed. In dry heat (grilling, broiling, baking, roasting, searing, sautéing), 120 °C (248 °F) for 1 hour kills all spores on the exposed surface.
In case of foodborne illness, the diagnosis of B. cereus can be confirmed by the isolation of more than 100,000 B. cereus organisms per gram from epidemiologically-implicated food, but such testing is often not done because the illness is relatively harmless and usually self-limiting.
For the isolation and enumeration of B. cereus, there are two standardized methods by International Organization for Standardization (ISO): ISO 7932 and ISO 21871. Because of B. cereus' ability to produce lecithinase and its inability to ferment mannitol, there are some proper selective media for its isolation and identification such as mannitol-egg yolk-polymyxin (MYP) and polymyxin-pyruvate-egg yolk-mannitol-bromothymol blue agar (PEMBA). B. cereus colonies on MYP have a violet-red background and are surrounded by a zone of egg-yolk precipitate.
Below is a list of differential techniques and results that can help to identify B. cereus from other bacteria and Bacillus species.
Anaerobic growth: Positive
Voges Proskauer test: Positive
Acid produced from
d-glucose: Positive
l-arabinose: Negative
d-xylose: Negative
d-mannitol: Negative
Starch hydrolysis: Positive
Nitrate reduction: Positive
Degradation of tyrosine: Positive
Growth at
above 50 °C: Negative
Use of citrate: Positive
The Central Public Health Laboratory in the United Kingdom tests for motility, hemolysis, rhizoid growth, susceptibility to γ-phage, and fermentation of ammonium salt-based glucose but no mannitol, arabinose, or xylose.
