Bacteriology Laboratory, Department of P.G. Studies and Research in Biological Science, R.D. University, Jabalpur, 482001 MP India.
Indian J Microbiol. 2009 Sep;49(3):259-65. doi: 10.1007/s12088-009-0046-5. Epub 2009 Aug 20.
Water samples of the river Narmada from the source to the mouth were analyzed for the presence of shigellae and the Shigella isolates from 180 water samples were characterized by biotyping, serotyping and molecular typing. Out of all the 40 isolates, 23 were identified as S. flexneri, 10 as S. sonnei and 7 as S. dysenteriae. Serotyping was found to be the better identification method than biotyping. In the present investigation, amplified ribosomal DNA restriction analysis (ARDRA) with a probe complementary to 16S rRNA was performed. Repeated ARDRA analysis established the similarities between the isolates and thus suggested ARDRA as authentic and precise detection protocol. The isolates were also analyzed for the presence of virulence genes including ipaBCD, ipaH and stx1. All the 40 isolates of Shigella were found to be positive for the ipaH gene. The plasmid encoded invasion-associated genes ipaBCD were present only in S. flexneri and the stx1 gene was found only in S. dysenteriae. This study demonstrated the existence of Shigella in the river Narmada and the dispersion of different virulence genes among the isolates, which appear to constitute an environmental reservoir of Shigella-specific virulence genes.
对纳马达河从源头到河口的水样进行了志贺氏菌检测，从 180 个水样中分离出的志贺氏菌分离株通过生物分型、血清分型和分子分型进行了特征描述。在所有 40 个分离株中，23 个被鉴定为福氏志贺氏菌，10 个为宋内志贺氏菌，7 个为痢疾志贺氏菌。血清分型被发现是比生物分型更好的鉴定方法。在本研究中，使用与 16S rRNA 互补的探针进行了扩增核糖体 DNA 限制分析（ARDRA）。重复的 ARDRA 分析确定了分离株之间的相似性，因此表明 ARDRA 是一种真实和精确的检测方案。还分析了分离株中存在的毒力基因，包括 ipaBCD、ipaH 和 stx1。所有 40 株志贺氏菌分离株均被发现携带 ipaH 基因。质粒编码的侵袭相关基因 ipaBCD 仅存在于福氏志贺氏菌中，stx1 基因仅存在于痢疾志贺氏菌中。本研究证明了纳马达河中存在志贺氏菌，以及不同毒力基因在分离株中的分布，这似乎构成了志贺氏菌特异性毒力基因的环境储库。
