Abriouel Hikmate, Ben Omar Nabil, Lucas López Rosario, Martínez Cañamero Magdalena, Ortega Elena, Gálvez Antonio
Area de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071-Jaén, Spain.
J Food Prot. 2007 May;70(5):1165-73. doi: 10.4315/0362-028x-70.5.1165.
Poto poto (a maize sourdough) and dégué (a pearl millet-based food) are two traditional African fermented foods. The molecular biology of toxigenic and pathogenic bacteria found in those foods is largely unknown. The purpose of this study was to study the phylogenetic relatedness and toxigenic potential of 26 Bacillus cereus group isolates from these traditional fermented foods. The relatedness of the isolates was evaluated with repetitive element sequence-based PCR (REP-PCR) and 16S rDNA sequencing analysis. A multiplex real-time PCR assay targeting the lef and capC genes of B. anthracis pXO1 and pXO2 plasmids and the sspE chromosomal gene of B. cereus and B. anthracis also was carried out. Melting curve analysis of the sspE amplification product was used to differentiate B. cereus from B. anthracis, and the presence of the B. cereus enterotoxin genes was determined with PCR amplification. Isolates had 15 different REP-PCR profiles, according to which they could be clustered into four groups. 16S rDNA sequencing analysis identified 23 isolates as B. cereus or B. anthracis and three isolates as B. cereus or Bacillus sp. Multiplex real-time PCR amplification indicated the absence of the lef and capC genes of B. anthracis pXO 1 and pXO2 plasmids, and melting curve analysis revealed amplification of the 71-bp sspE product typical of B. cereus in all isolates instead of the 188-bp amplicon of B. anthracis, confirming the identity of these isolates as B. cereus. Four isolates had amylolytic activity. All isolates had lecithinase activity and beta-hemolytic activity. Enterotoxin production was detected in two isolates. The emetic toxin gene was not detected in any isolate. The nheB toxin gene was detected in 19 isolates by PCR amplification; one of these isolates also contained the hblD (L1) gene. The cytotoxin K cytK-1 gene was not detected, but the cytK-2 gene was clearly detected in six isolates.
波托波托（一种玉米酸面团）和德盖（一种基于珍珠粟的食品）是两种传统的非洲发酵食品。这些食品中发现的产毒和致病细菌的分子生物学在很大程度上尚不清楚。本研究的目的是研究从这些传统发酵食品中分离出的26株蜡样芽孢杆菌属菌株的系统发育相关性和产毒潜力。通过基于重复元件序列的PCR（REP-PCR）和16S rDNA测序分析评估分离株的相关性。还进行了针对炭疽芽孢杆菌pXO1和pXO2质粒的lef和capC基因以及蜡样芽孢杆菌和炭疽芽孢杆菌的sspE染色体基因的多重实时PCR检测。利用sspE扩增产物的熔解曲线分析来区分蜡样芽孢杆菌和炭疽芽孢杆菌，并通过PCR扩增确定蜡样芽孢杆菌肠毒素基因的存在。分离株有15种不同的REP-PCR图谱，据此可分为四组。16S rDNA测序分析鉴定出23株为蜡样芽孢杆菌或炭疽芽孢杆菌，3株为蜡样芽孢杆菌或芽孢杆菌属。多重实时PCR扩增表明不存在炭疽芽孢杆菌pXO 1和pXO2质粒的lef和capC基因，熔解曲线分析显示所有分离株中均扩增出蜡样芽孢杆菌典型的71 bp sspE产物，而非炭疽芽孢杆菌的188 bp扩增子，证实这些分离株为蜡样芽孢杆菌。4株分离株具有淀粉酶活性。所有分离株均具有卵磷脂酶活性和β溶血活性。在2株分离株中检测到肠毒素产生。在任何分离株中均未检测到呕吐毒素基因。通过PCR扩增在19株分离株中检测到nheB毒素基因；其中一株还含有hblD（L1）基因。未检测到细胞毒素K cytK-1基因，但在6株分离株中明确检测到cytK-2基因。
