Detection of genes encoding for enterotoxins and determination of the production of enterotoxins by HBL blood plates and immunoassays of psychrotrophic strains of Bacillus cereus isolated from pasteurised milk.
The presence of genes for the production of the three components of the HBL enterotoxin complex and enterotoxin-T in Bacillus cereus was evaluated by PCR tests for strains isolated from milk. In addition enterotoxin production of B. cereus was evaluated by means of the HBL blood agar plate and two commercially available toxin tests. All three genes for the HBL enterotoxin complex were detected in 55% of the 86 strains tested, the enterotoxin-T gene was detected in 62% of the strains. A few strains showed a weak reaction in the PCR tests for the L1 or L2 components of the HBL enterotoxin complex. Many strains that were found to contain the genes for the HBL complex gave negative or doubtful results in the HBL blood agar plate test. All strains that contain the L2 part of the HBL complex showed a titer of at least 8 in the Oxoid RPLA test. Two strains that did not contain the L2 part of the HBL enterotoxin complex gave high titers (= 64) in the RPLA test.
Microbiological Laboratory for Health Protection, National Institute of Public Health and the Environment, Bilthoven, The Netherlands.
P H
PH
in't Veld
W S
WS
Ritmeester
E H
EH
Delfgou-van Asch
J B
JB
Dufrenne
K
K
Wernars
E
E
Smit
F M
FM
van Leusden
D000818:Animals; D001409:Bacillus cereus / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001426:Bacterial Proteins; D002417:Cattle; D017931:DNA Primers; D004269:DNA, Bacterial; D004768:Enterotoxins / Q000096:biosynthesis*; D005260:Female; D005517:Foodborne Diseases / Q000517:prevention & control; D006460:Hemolysin Proteins; D007118:Immunoassay; D008892:Milk / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D013997:Time Factors
D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D004768:Enterotoxins; D006460:Hemolysin Proteins; C083961:hemolysin BL protein, Bacillus