仔猪雷极氏普罗菲登斯菌的分离鉴定及系统进化分析

Isolation,Identification and Phylogenetic Analysis of Providencia rettgeri in Piglets

为了解猪雷极氏普罗菲登斯菌（P.rettgeri）的生物学特性、致病性及16SrRNA基因系统进化关系,从发生严重腹泻、血便的哺乳仔猪群的内脏器官中分离到1株病原菌,根据形态特征、培养特性、生化特性、16SrRNA基因序列分析鉴定为P.rettgeri。小鼠攻毒试验证实,该分离菌株对试验小鼠有较强致病力,哺乳仔猪回归试验可复制出与临床上相似的典型症状,并从发病死亡小鼠及哺乳仔猪中分离到攻毒菌株。系统进化分析表明,分离菌株与雷极氏普罗菲登斯菌系统进化关系最为密切,其16SrRNA基因序列与雷极氏普罗菲登斯菌代表菌株的同源性在97.3%-99.6%之间。药敏试验结果表明,分离菌株对头孢哌酮钠、头孢噻肟钠、头孢曲松钠、头孢唑啉、头孢呋肟、头孢吡肟、阿莫西林、链霉素、氨曲南、诺氟沙星、左氟沙星、恩诺沙星、卡那霉素、氨苄青霉素、米诺环素、链霉素、阿米卡星等多数药物敏感。首次报道了雷极氏普罗菲登斯菌可以引起哺乳仔猪严重腹泻,提示在仔猪腹泻中应注意该菌感染的诊断、监测和防控。

Investigation of a serious piglet disease with high mortality and typical diarrhea yielded a bacteri-al isolate identified as Providencia rettgeri based on the morphological characteristics,physiological,bio-chemical characteristics and 1 6 S ribosomal DNA sequence analysis.The pathogenicity of this bacterial iso-late was confirmed in mice,and the same clinical signs were observed in 5-day-old piglets inoculated with Providenciarettgeri Guangxi 2013 at 5.0×10^9 CFU.The same bacterial were recovered from the samples collected from died mice and piglets based on bacteria staining or biochemical test results.Phylogenetic a-nalysis showed the isolated strain had the nearest relationship with the P.rettgeri strains,and shared 97.3%-99.6% homology of 16 S rRNA with those strains.The drug resistance spectrum of the bacterium was also determined.The results indicated that the isolate is sensitive to 1 7 antimicrobials out of the 2 9 an-timicrobials tested.The current study is the first to report a serious diarrheal disease in piglets infected with P.reggteri isolate,which should give more attention during surveillance and diagnostics.