东莞某屠宰场猪链球菌检测及分离鉴定

Detection,Isolation and Identification of Streptococcus suis in A Slaughterhouse in Dongguan

【目的】猪链球菌(Streptococcus suis,SS)是一种重要的猪病原菌,也是一种人兽共患病病原体。其中猪链球菌2型(SS2)致病力最强,不但引起猪的急性败血症、脑膜炎、关节炎甚至死亡,也可导致人的感染和死亡。为评估屠宰场猪链球菌的传播风险,对东莞某屠宰场进行猪链球菌的采样检测和分离鉴定。【方法】采集40头猪的关节液和扁桃体进行PCR检测和猪链球菌分离,分离菌分别进行形态学和生理生化鉴定、16S rDNA PCR扩增、分型PCR检测和抗生素敏感性试验。【结果】对40头猪的关节液和扁桃体提取DNA进行PCR检测,在40份关节液中,猪链球菌阳性率为22.5%,但未检出猪链球菌2型阳性;在40份扁桃体样品中,猪链球菌阳性率为32.5%,其中猪链球菌2型阳性率为7.5%。从40头猪的扁桃体和关节液共80份样品中分离出3株猪链球菌,PCR结果表明,3株分离菌中1株为猪链球菌4型,基因型为epfmrp+gdh+gapdh+fbps-orf2+sly-;其他2株为猪链球菌9型,基因型分别为epf-mrp+gdh+gapdh+fbps-orf2+sly-和epf-mrp-gdh+gapdh+fbps-orf2+sly+。药敏试验表明,3株猪链球菌菌株对青霉素G、林可霉素、多粘菌素B和磺胺异恶唑耐药,对恩诺沙星、环丙沙星、大观霉素和阿莫西林敏感。【结论】该屠宰场猪群中存在猪链球菌的隐性感染,提示存在猪链球菌2型感染人的风险。

【Objective】Streptococcus suis(SS) is an important porcine pathogen and a zoonotic pathogen.Among various types,Streptococcus suis type 2(SS2) has the strongest pathogenicity.It can not only cause acute sepsis,meningitis,arthritis and even death in pigs,but also lead to human infection and death.In order to evaluate the transmission risks of SS in slaughterhouses,the sampling,detection,isolation and identification of SS were carried out in a slaughterhouse in Dongguan.【Method】The synovial fluid and tonsils of 40 pigs were collected for PCR detection and SS isolation.The isolated strains were used for morphology,physiology and biochemistry identification,16S rDNA PCR amplification,typing PCR detection and antibiotic sensitivity test.【Result】The nucleic acids extracted from the synovial fluid and tonsils of 40pigs were detected by PCR.In 40 synovial fluids,the positive rate of SS was 22.5%,but no SS2 was detected.In 40 tonsil samples,the positive rate of SS was 32.5%,in which the positive rate of SS2 was 7.5%.Three strains of SS were isolated from 80 tonsil and synovial fluid samples of 40 pigs.The PCR results showed that one of the three strains was SS type 4,and the genotype was epf-mrp+gdh+gapdh+fbps-orf2+sly-;while the other two strains were SS type 9,and the genotypes were epfmrp+gdh+gapdh+fbps-orf2+sly-and epf-mrp-gdh+gapdh+fbps-orf2+sly+,respectively.The drug sensitivity test showed that the three SS strains were resistant to penicillin G,lincomycin,polymyxin B and sulfaisoxazole,and sensitive to enrofloxacin,ciprofloxacin,spectinomycin and amoxicillin.【Conclusion】The results suggest that there are a large number of recessive infection of SS in the pigs of the slaughterhouse,and there is a risk of human infection by SS2.