<i>Bacillus</i>Identification ‐ Traditional Approaches

Fritze, Dagmar

doi:10.1002/9780470696743.ch8

Cited by 14 publications

(11 citation statements)

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“…Bacillus cereus spores are ellipsoidal, centrally or paracentrally placed, and do not distend the cell (Gilbert & Kramer, 1986). Employing phase contrast microscopy or spore staining techniques, the placement and morphology of the spores are much used criteria to distinguish the species of the genus Bacillus (Fritze, 2002). Other commonly used features for identification are motility, haemolysis, carbohydrate fermentation ( B. cereus does not ferment mannitol) and the very active lecithinase (phospholipase) production (Johnson, 1984).…”

Section: The Organism: Characteristics and Identificationmentioning

confidence: 99%

From soil to gut:Bacillus cereusand its food poisoning toxins

2008

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Bacillus cereus is widespread in nature and frequently isolated from soil and growing plants, but it is also well adapted for growth in the intestinal tract of insects and mammals. From these habitats it is easily spread to foods, where it may cause an emetic or a diarrhoeal type of food-associated illness that is becoming increasingly important in the industrialized world. The emetic disease is a food intoxication caused by cereulide, a small ring-formed dodecadepsipeptide. Similar to the virulence determinants that distinguish Bacillus thuringiensis and Bacillus anthracis from B. cereus, the genetic determinants of cereulide are plasmid-borne. The diarrhoeal syndrome of B. cereus is an infection caused by vegetative cells, ingested as viable cells or spores, thought to produce protein enterotoxins in the small intestine. Three pore-forming cytotoxins have been associated with diarrhoeal disease: haemolysin BL (Hbl), nonhaemolytic enterotoxin (Nhe) and cytotoxin K. Hbl and Nhe are homologous three-component toxins, which appear to be related to the monooligomeric toxin cytolysin A found in Escherichia coli. This review will focus on the toxins associated with foodborne diseases frequently caused by B. cereus. The disease characteristics are described, and recent findings regarding the associated toxins are discussed, as well as the present knowledge on virulence regulation.

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Section: The Organism: Characteristics and Identificationmentioning

confidence: 99%

From soil to gut:Bacillus cereusand its food poisoning toxins

2008

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“…Aerobic, endospore‐forming bacteria are a heterogenic group of micro‐organisms, and the genus Bacillus is one of 16 validly published genera in this group (Fritze 2002). Most Bacillus spp.…”

Section: Introductionmentioning

confidence: 99%

“…are of special interest; the B. cereus group and the B. subtilis group. Members of the B. cereus group are B. cereus , B. anthracis , B. mycoides , B. thuringiensis , B. pseudomycoides and B. weihenstephanensis (Fritze 2002). The role of B. cereus as a food‐borne pathogen was recently reviewed by Granum (2002).…”

Section: Introductionmentioning

confidence: 99%

“…Other Bacillus spp., primarily members of the B. subtilis group have also been related to food‐borne illness (Kramer and Gilbert 1986; Granum and Baird‐Parker 2000). The most important organisms of this group are B. subtilis , B. licheniformis and B. pumilus (Fritze 2002). Additionally, Bacillus spp.…”

Section: Introductionmentioning

confidence: 99%

“…Based on spore and sporangium shape, Bacillus spp. is arranged into five groups (Fritze 2002). In addition, biochemical tests, such as API 50 CHB/API 20 E, are commonly used for species identification (Logan 2002).…”

Section: Introductionmentioning

confidence: 99%

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Cytotoxic Bacillus spp. belonging to the B. cereus and B. subtilis groups in Norwegian surface waters

et al. 2004

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Aims: To investigate the presence and numbers of Bacillus spp. spores in surface waters and examine isolates belonging to the B. cereus and B. subtilis groups for cytotoxicity, and to discuss the presence of cytotoxic Bacillus spp. in surface water as hazard identification in a risk assessment approach in the food industry. Methods and Results: Samples from eight different rivers with variable degree of faecal pollution, and two drinking water sources, were heat shocked and examined for the presence of Bacillus spp. spores using membrane filtration followed by cultivation on bovine blood agar plates. Bacillus spp. was present in all samples. The numbers varied from 15 to 1400 CFU 100 ml )1 . Pure cultures of 86 Bacillus spp. isolates representing all sampling sites were characterized using colony morphology, atmospheric requirements, spore and sporangium morphology, and API 50 CHB and API 20E. Bacillus spp. representing the B. cereus and B. subtilis groups were isolated from all samples. Twenty-one isolates belonging to the B. cereus and B. subtilis groups, representing eight samples, were screened for cytotoxicity. Nine strains of B. cereus and five strains belonging to the B. subtilis group were cytotoxic. Conclusions: The presence of cytotoxic Bacillus spp. in surface water represents a possible source for food contamination. Filtration and chlorination of surface water, the most common drinking water treatment in Norway, do not remove Bacillus spores efficiently. This was confirmed by isolation of spores from tap water samples. Significance and Impact of the Study: Contamination of food with water containing low numbers of Bacillus spores implies a risk for bacterial growth in foods. Consequently, high numbers of Bacillus spp. may occur after growth in some products. High numbers of cytotoxic Bacillus spp. in foods may represent a risk for food poisoning.

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