江苏某牛场奶牛乳房炎病原菌的分离鉴定、耐药性及保守抗原分析

Isolation, antibiotic-resistance and conservative antigen analysis of cow mastitis related pathogens from one dairy farm at Jiangsu province

2018年6月对江苏某奶牛场30头隐性乳房炎奶牛的50个发病乳区采集生牛乳进行检测,分离鉴定主要病原菌,其中大肠埃希菌19株(38%)、肺炎克雷伯菌13株(26%)、金黄色葡萄球菌5株(10%)、凝固酶阴性葡萄球菌11株(22%)、无乳链球菌4株(8%)、停乳链球菌1株(2%)。采用PCR和血清学方法对金黄色葡萄球菌分离株进行分型,结果显示5株金黄色葡萄球菌中4株为CP8型(80%),1株为非CP5、CP8或336PS型。耐药性分析结果显示该牛场松鼠葡萄球菌菌株对磺胺类药物复方新诺明和广谱抗菌药甲氧胺嘧啶表现双重耐药,耐药率达100%;肺炎克雷伯菌对利福平和万古霉素表现双重耐药,耐药率达100%。此外,部分葡萄球菌、链球菌、肺炎克雷伯菌和大肠埃希菌对四环素、红霉素、克林霉素和克拉霉素表现出中度敏感。但所有菌株对头孢哌酮、链霉素、庆大霉素、妥布霉素、氯霉素和呋喃妥因表现高度敏感,敏感率100%。通过PCR方法检测发现,在分离菌株中金黄色葡萄球菌TraP和FnbpA,无乳链球菌GapC和Sip,大肠埃希菌Lpf1A等保守抗原检出率高达89%~100%,证明其作为亚单位疫苗候选抗原的普适性。这一研究为该牛场乳房炎的临床用药和综合防控提供了参考依据。

Sampling of raw milk from 50 pathogenic udder quarters of 30 subclinical mastitis cows was done at a dairy farm in Jiangsu province,in June 2018.Varity species of pathogen including 19 Escherichia coli strains(38%),13 Klebsiella pneumoniae strains(26%),5 Staphylococcus aureus strains(10%),11 Coagulase-negative Staphylococcus strains(22%),4 Streptococcus agalactiae strains(8%)and 1 Streptococcus dysgalactiae strain(2%)were isolated and identified.By using both PCR and serology methods,4 of 5(80%)S.aureus strains were typing into serotype CP8,while the last one belonged none of serotype CP5,CP8 or 336 PS.Antibiotic-resistance analysis showed that all Staphylococcus sciuri strians in this field owned the muti-drug resistance against trimethoprim/sulfamethoxazole and methoxyamine.Multi-drug resistance rate of Klebsiella pneumoniae strains against rifampicin and vancomycin was 100%.Moreover,some Staphylococcus spp.,Streptococcus spp.,Klebsiella pneumoniae and Escherichia coli strains sense had medium sensitivity to tetracycline,erythrocin,clindamycin and clarithromycin.Nevertheless,all isolates were highly sensitive to cefoperazone,streptomycin,gentamicin,tobramycin,chloramphenicol and furantoin.We also verified the high prevalence(89%-100%)of those conserved antigen by PCR,including TraP and FnbpA of S.aureus,GapC and Sip of S.agalactiae,and Lpf1 Aof E.coli,which can be used as candidates for subunit vaccine development.In summary,this study provided a reliable foundation for clinical treatment and comprehensive prevention against cows mastitis in this dairy farm.