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

Abstract

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.

Determination of Toxigenic Potentials of Bacillus Strains Isolated from Okpehe, a Nigerian Fermented Condiment

“…This showed that the organism can proliferate and produce toxin during the fermentation. The ability of B. cereus to contaminate food during processing has been reported (Ostensvik et al 2004). The results of our study established the possibility of this bacterium being a source of diarrhoea in Nigeria.…”

“…Among the strains of B. subtilis group studied in this work, diarrhoeagenic enterotoxin gene was only detected in B. licheniformis Lag1, although some of the isolates in this group were haemolytic on Colombia blood agar, the haemolysis on the blood agar does not confirm toxigenicity of the isolate similar observation has earlier been made (Ostensvik et al 2004). There is a dearth of information about the epidemiology of bacilli food borne diseases in Nigeria, but diseases from non-B.…”

Rapid Ped-2E9 Cell-Based Cytotoxicity Analysis and Genotyping of Bacillus Species

“…As mentioned before, B. cereus produces multiple toxins, including hemolysins (HBL; 37.8, 38.5, and 43.5 kDa) (33) and NHE (39,45, and 105 kDa) (40). Based on the protein analysis data, PCR results, and hemolysis on blood agar plates, we speculate that cytotoxic action on Ped-2E9 cells could be due to the NHE and/or HBL components, since these toxins were also found to be involved in cytotoxic activities by using other cell lines (39). As indicated above, HBL possibly enhances Ped-2E9 cytotoxicity induced by NHE but is not essential.…”

Assessment of Bacterial Contamination of Indian Paper Currency Notes (Rupee) Circulating in Hapur (U.P.), India.

“…In the present study, the isolation of Gram's positive as well as Gram's negative bacteria from currency notes confirmed that currency might be playing an important role as a vector in the transmission of pathogenic bacteria in the community. For example some strains of Bacillus have been reported to be involved in food poisoning (Ostensvik et al, 2004). Similarly, Micrococcus sp.…”