Ouoba Labia Irene I, Thorsen Line, Varnam Alan H
London Metropolitan University, Department of Health and Human Sciences, Microbiology Research Unit, 166-220 Holloway Road, London N7 8DB, United Kingdom.
Int J Food Microbiol. 2008 Jun 10;124(3):224-30. doi: 10.1016/j.ijfoodmicro.2008.03.026. Epub 2008 Mar 30.
The ability of various species of Bacillus from fermented seeds of Parkia biglobosa known as African locust bean (Soumbala) and fermented seeds of Hibiscus sabdariffa (Bikalga) was investigated. The study included screening of the isolates by haemolysis on blood agar, detection of toxins in broth and during the fermentation of African locust bean using the Bacillus cereus Enterotoxin Reverse Passive Latex Agglutination test kit (BCET-RPLA) and the Bacillus Diarrhoeal Enterotoxin Visual Immunoassay (BDEVIA). Detection of genes encoding cytotoxin K (CytK), haemolysin BL (Hbl A, Hbl C, Hbl D), non-hemolytic enterotoxin (NheA, NheB, NheC) and EM1 specific of emetic toxin producers was also investigated using PCR with single pair and multiplex primers. Of 41 isolates, 29 Bacillus belonging to the species of B. cereus, Bacillus subtilis, Bacillus licheniformis and Bacillus pumilus showed haemolysis on blood agar. Using RPLA, enterotoxin production was detected for three isolates of B. cereus in broth and all B. cereus (9) in fermented seeds. Using BDEVIA, enterotoxin production was detected in broth as well as in fermented seeds for all B. cereus isolates. None of the isolates belonging to the other Bacillus species was able to produce enterotoxins either by RPLA or BDEVIA. Nhe genes were detected in all B. cereus while Hbl and CytK genes were detected respectively in five and six B. cereus strains. A weak presence of Hbl (A, D) and CytK genes was detected in two isolates of B. subtilis and one of B. licheniformis but results were inconsistent, especially for Hbl genes. The emetic specific gene fragment EM1 was not detected in any of the isolates studied.
对来自被称为非洲刺槐豆（Soumbala）的大果朴发酵种子以及玫瑰茄（Bikalga）发酵种子中的各种芽孢杆菌的能力进行了研究。该研究包括通过在血琼脂上的溶血反应对分离株进行筛选，使用蜡样芽孢杆菌肠毒素反向被动乳胶凝集试验试剂盒（BCET - RPLA）和芽孢杆菌腹泻性肠毒素视觉免疫测定法（BDEVIA）检测肉汤以及非洲刺槐豆发酵过程中的毒素。还使用单对引物和多重引物通过PCR研究了编码细胞毒素K（CytK）、溶血素BL（Hbl A、Hbl C、Hbl D）、非溶血肠毒素（NheA、NheB、NheC）以及呕吐毒素产生菌特有的EM1的基因。在41株分离株中，29株属于蜡样芽孢杆菌、枯草芽孢杆菌、地衣芽孢杆菌和短小芽孢杆菌的芽孢杆菌在血琼脂上显示出溶血现象。使用RPLA，在肉汤中检测到3株蜡样芽孢杆菌的肠毒素产生，在发酵种子中的所有蜡样芽孢杆菌（9株）中也检测到肠毒素产生。使用BDEVIA，在所有蜡样芽孢杆菌分离株的肉汤和发酵种子中均检测到肠毒素产生。属于其他芽孢杆菌属的分离株通过RPLA或BDEVIA均无法产生肠毒素。在所有蜡样芽孢杆菌中均检测到Nhe基因，而Hbl和CytK基因分别在5株和6株蜡样芽孢杆菌菌株中检测到。在2株枯草芽孢杆菌分离株和1株地衣芽孢杆菌分离株中检测到Hbl（A、D）和CytK基因的微弱存在，但结果不一致，尤其是对于Hbl基因。在所研究的任何分离株中均未检测到呕吐特异性基因片段EM1。
