Department of Microbiology, Regeneration and Advanced Medical Science, Gifu University Graduate School of Medicine, Gifu, Japan.
Diagn Microbiol Infect Dis. 2011 Jul;70(3):307-15. doi: 10.1016/j.diagmicrobio.2011.02.012.
Bacillus cereus is becoming an important nomosomial pathogen because of frequent isolation from blood cultures and from severe systemic infections. To differentiate highly pathogenic outbreak strain of B. cereus from other sources of the Bacillus cereus, we attempted to analyze their dnaJ sequences. Assays indicated that dnaJ sequence similarity of all of 52 blood culture isolates of B. cereus ranged from 92.8% to 100%. The distance between B. anthracis and B. cereus except six outbreak isolates ranged from 3.8% to 6.4%. The dnaJ sequences of six outbreak strains of B. cereus (GTC 02891, GTC 02896, GTC 02916, GTC 02917, GTC 03221, and GTC 03222) were closely related to those of B. anthracis (99.2%-99.5% sequence similarity). Ba813 sequences were only found in the six outbreak strains of B. cereus. The other pathogenic factors of B. anthracis were not found in these six outbreak strains, with the exception of GTC 02891 (cap-positive). The six outbreak strains formed clear β-hemolytic colonies on a sheep blood agar plate. Our findings suggest that outbreak strains of B. cereus isolated from blood cultures are likely to have the risk of causing serious infection, and dnaJ and Ba813 are important markers to identify such strains. Phylogenetic analysis of dnaJ and MLST revealed that the six outbreak strains of B. cereus are closely related to B. anthracis.
蜡样芽胞杆菌由于经常从血培养和严重的全身感染中分离出来，因此成为一种重要的医院病原体。为了将高致病性暴发株蜡样芽胞杆菌与其他来源的蜡样芽胞杆菌区分开来，我们试图分析它们的 dnaJ 序列。试验表明，52 株血培养蜡样芽胞杆菌的 dnaJ 序列相似性在 92.8%至 100%之间。除了 6 株暴发株外，炭疽芽孢杆菌和蜡样芽胞杆菌之间的距离在 3.8%至 6.4%之间。6 株暴发株蜡样芽胞杆菌（GTC 02891、GTC 02896、GTC 02916、GTC 02917、GTC 03221 和 GTC 03222）的 dnaJ 序列与炭疽芽孢杆菌（99.2%-99.5%序列相似性）密切相关。Ba813 序列仅在这 6 株暴发株蜡样芽胞杆菌中发现。除了 GTC 02891（荚膜阳性）外，这些暴发株中没有发现炭疽芽孢杆菌的其他致病因子。6 株暴发株在绵羊血琼脂平板上形成清晰的β-溶血菌落。我们的研究结果表明，从血培养中分离出的暴发株蜡样芽胞杆菌可能有引起严重感染的风险，dnaJ 和 Ba813 是识别这些菌株的重要标记。dnaJ 和 MLST 的系统发育分析表明，这 6 株暴发株蜡样芽胞杆菌与炭疽芽孢杆菌密切相关。
