从一例多细菌协同性坏疽的标本中分离到罕见芽孢杆菌

An unusual strain of Bacillus isolated from a patient with multiple bacterial synergistic gangrene

目的 确定从一例多细菌协同性坏疽患者临床标本中分离的、使用常规方法不能够鉴定的YP菌株的分类学位置。方法 使用 16SrRNA序列分析和同源性检索方法 ,及细菌的形态学和生化反应鉴定方法。结果 YP菌株为革兰氏阳性杆菌 ,可在厌氧和有氧条件下生长 ,在LB琼脂上有氧条件下培养 48h后产生端生芽孢。触酶阳性 ,无动力 ,硝酸盐还原。在PYG肉汤中的代谢产物主要为乙酸、乳酸以及少量的琥珀酸和异戊酸。G +Cmol%为 33。 16SrRNA序列分析和同源性检索发现YP和芽孢杆菌一些种的同源性较高 ,可达 96 %。但和已经发表的芽孢杆菌属的细菌种有明显区别。结论 YP菌株在分类学上应该属于芽孢杆菌属 ,但是和芽孢杆菌属已经发表的种都不相同 ,可能是一个新种。

Objective The aim of this study was to classify the unusual gram positive rod isolated from a patient with multiple bacterial synergistic gangrene. Methods The 16S rRNA fragment cloning, sequencing, 16S rRNA similarity searching, bacterial morphological and biochemical tests were used. Results YP strain was facultative aerobic, spore forming on LB agar in the presence of oxygen. Catalase positive, no motility, nitrate reduced. The end products in PYG broth were mainly acetic acid, lactic acid and small amount of succinate acid. The YP strain could not be identified by routine method. The 1457 base pair 16S rRNA of YP strain was synthesized by PCR and sequenced. Comparative 16S rRNA sequence analyses revealed that stain YP is most closely related to several species and some unnamed strains of Bacillus. The highest similarity value between Y6 strain and members of Bacillus could reach up to 96%. However, the most closed is a nonspore forming species. Conclusion Based on the biological and genetic results obtained, we named YP strain genus Bacillus, which has the potential to be a new species pathogenic to human being.