1株与大肠埃希菌O157生化结果相似的 志贺氏菌的鉴定

Identification of a strain of Shigella with biochemical features similar to Escherichia coli O157

中文关键词:  志贺氏菌  生化试验  血清学试验  16S rDNA序列

英文关键词:Shigella  biochemical tests  serological test  16S rDNA sequence

中文摘要:

      目的 对一菌株sznjO23进行分析鉴定。方法 从猪肝中分离到菌株sznjO23, 并对该菌株的菌落形态、生化特征及分子生物学特性进行分析。结果 该菌株在CT-SMAC平板上呈圆形、光滑、较小的无色菌落, 在改良CHROMagar O157显色平板上为紫色圆形的菌落。经全自动微生物鉴定分析系统VITEK 2 Compact鉴定, 其生化结果96%可能性为大肠埃希菌O157, 但血清学试验结果反应完全混浊, 未出现任何凝集。16S rDNA序列分析发现, 该菌株与志贺氏菌(ATCC29903)的进化距离较近、同源性高, 相似度为99.26%。结论 菌株sznjO23为志贺氏菌。当生化试验、血清学试验结果不一致时可选择16S rDNA序列分析的方法进行鉴定, 以保证结果的准确性。

英文摘要:

      Objective To analyze and identify a bacterium of sznjO23. Methods A strain of sznjO23 was isolated from pig’s liver, and the colonial morphology, biochemical features, and molecular biological characteristics of the strain were analyzed. Results Its colonies features on CT-SMAC were rounded, smooth, small, and colorless, while the strain became purple and circular on CHROMagar O157. Biochemical results showed that the strain had 96% possibility to be E. coli O157 by VITEK 2 Compact. Serology reaction was cloudy, and it didn’t appear any agglutination. The sequence analysis result of 16S rDNA showed that the strain was closed to Shigella (ATCC29903) from evolutionary distance with the similarity of 99.26%. Conclusion The strain of sznjO23 was Shigella. When the results of biochemical tests and serological test were inconsistent, 16S rDNA sequence analysis can be used in order to ensure the accuracy of the results.