陕西扶风某生猪养殖场肠球菌分型与毒力基因检测

Subtyping and virulence gene detection of Enterococci isolates derived from a pig farm in Fufeng,Shaanxi

[目的]分析分离自陕西扶风某生猪养殖场的肠球菌的亚型及毒力基因携带情况,为保障猪肉食品安全和临床感染治疗提供依据。[方法]采用PCR方法,对从陕西省扶风县某养殖场生猪鼻腔、粪便及其养殖场环境样品中分离到的87株肠球菌进行粪肠球菌(Enterococcus faecalis)、屎肠球菌(Enterococcus faecium)、鸡肠球菌(Enterococcus gallinarum)特异性基因的扩增,根据凝胶成像中条带位置对其进行分型,检测其ace、cylA、cylB、cylM、cylL1、efaA、esp、gelE、AS、asal和hyl等11种毒力基因的携带情况。[结果]87株肠球菌中,粪肠球菌、屎肠球菌、鸡肠球菌和其他类型肠球菌(Other Enterococcus)的检出率分别为57.5%,10.3%,4.6%和27.6%;5种毒力基因asal、gelE、cylL1、ace和esp的平均检出率分别为50.6%,27.6%,19.5%,18.4%和1.2%,在猪舍地面菌株中均有检出。粪肠球菌中的asal检出率显著高于其他4种毒力基因(P<0.05),各毒力基因在未定型的其他亚型肠球菌中的检出率无显著差异(P>0.05)。在生猪育肥前期和后期,所有源菌株中毒力基因ace、cylL1、esp、gelE和asal的总检出率分别为93.7%和6.3%,82.3%和17.7%,100.0%和0%,75.0%和25.0%及84.1%和15.9%。[结论]扶风县某生猪养殖场中流行的肠球菌主要为粪肠球菌,其次为屎肠球菌和鸡肠球菌。不同来源菌株中毒力基因检出率不同,生猪育肥后期菌株中各毒力基因的检出率均有所降低。

[Objective] The subtype and virulence gene of Enterococci isolates recovered from a pig farm were investigated to ensure pork-related food safety and provide evidence for clinical infection treatment.[Method] Polymerase chain reaction(PCR) was used to amplify specific genes of Enterococcus faecalis,Enterococcus faecium,and Enterococcus gallinnarum isolated from pig nasal cavity, feces and farm environment in Fufeng, Shaanxi and the subtypes of 87 Enterococci strains were determined according to the position of bands in gel images.The same method was used to detect 11 virulence genes including ace,cylA,cylB,cylM,cylL1,efaA,esp,gelE,AS,asal and hyl in these isolates.[Result] Among the 87 Enterococci isolates, detection rates of Enterococcus faecalis,Enterococcus faecium,Enterococcus gallinnarum and other Enterococci were 57.5%,10.3%,4.6%,and 27.6%,respectively.The detection rates of virulence genes asal, gelE,cylL1,ace,and esp were 50.6%,27.6%,19.5%,18.4%,and 1.2%,and all isolates were detected from ground of pig farm.The detection rate of asal was significantly(P<0.05) higher than that of other four virulence genes in Enterococcus faecalis isolates, no significant difference(P>0.05) was found among the detection rates of the five virulence genes in Enterococcus isolates other than Enterococcus faecalis.Detection rates of ace,cylL1,esp,gelE and asal in all isolates recovered from the periods of pig-before-fattening and after-fattening were 93.7% and 6.3%;82.3% and 17.7%;100% and 0%;75.0%,25.0% and 84.1%,15.9%,respectively.[Conclusion] Enterococcus faecalis was the predominant subtype of Enterococcus isolates recovered from the pig farm in Fufeng, followed by Enterococcus faecium and Enterococcus gallinarum.Detection rates of virulence genes in Enterococcus strains differed among sources, and detection rates of virulence genes after fattening were lower than that before fattening.