摘要
旨在调查引起内蒙古地区奶牛临床型子宫内膜炎致病葡萄球菌的毒力基因分布情况及其耐药现状。本试验对采集自内蒙古不同地区的260份患有临床型子宫内膜炎奶牛的子宫脓性分泌物进行了葡萄球菌的分离鉴定,调查了超抗原毒素基因(SEs和TSST-1)的分布;采用微量肉汤稀释法测定了19种抗菌药物对分离菌株的MIC,并对红霉素和四环素耐药菌株携带的相关耐药基因进行了检测。结果显示,260份样品中分离到10种127株(48.8%)葡萄球菌,其中金黄色葡萄球菌53株(41.7%),凝固酶阴性葡萄球菌74株(58.3%);80株(63.0%)葡萄球菌至少携带1种超抗原毒素基因,超抗原基因可有17种不同的组合,其中sej(38.6%)检出率最高,sec+sej+sen(33.3%)组合最为流行。分离菌株对青霉素(79.5%)和氨苄西林(71.7%)耐药率最高,对头孢菌素类的耐药率在60%左右,对大环内酯类和四环素抗生素的耐药率均在40%左右,对氟喹诺酮类抗菌药物的耐药率在20%左右,对3种联合用药的抗菌药物组合耐药率均在10%左右,所有菌株均对万古霉素敏感。菌株对红霉素的耐药表型主要由ermC(46.4%)和ermB(37.5%)基因贡献,未检出ermA基因。菌株对四环素的耐药表型主要由tetK(70.0%)基因介导,其次为tetM(10.0%)基因。22株耐甲氧西林葡萄球菌(MRS)均为凝固酶阴性葡萄球菌;MRS菌株对青霉素、氨苄西林、克拉霉素和红霉素的耐药率极显著高于甲氧西林敏感葡萄球菌(MSS)(P<0.01),对头孢噻肟的耐药率高于MSS(P<0.05)。结果提示:内蒙古地区临床型奶牛子宫内膜炎葡萄球菌携带毒力基因复杂,耐药情况较为严重,且发现耐甲氧西林凝固酶阴性葡萄球菌的流行。抗微生物药的耐药性可能是导致内蒙古地区奶牛临床子宫内膜炎治疗失败的主要原因之一。
The aim of the study was to investigate the distribution of superantigen genes and the profile of antimicrobial resistance in staphylococcal strains isolated from dairy cows with clinical endomitritis in Inner Mongolia.A total of 260purulent secretions collected from bovine with clinical endomitritis were used for the isolation of Staphylococci and subsequently,the suspected strains were molecularly identified to species level.The distribution of staphylococcal superantigen toxin genes(SEs and TSST-1)was investigated by PCR.The MICs of 16antimicrobial a-gents and 3pairs of antimicrobial agents combinations to the isolates were determined by broth micro-dilution method.PCR was conducted to detect the presence of genes conferring resistance to erythromycin and tetracycline.A total of 127 Staphylococcus isolates belonging to 10varied species,including 53SA(41.7%)and 74CNS(58.3%),were isolated from 260clinical samples. Eighty isolates(63.0%)were found to harbor at least one staphylococcal superantigen toxin gene and the prevailing of 17different combinations of superantigen toxins genes was observed.Sej(38.6%)was the most frequently found and the'sec+sej+sen'(33.3%)was the most commonly encountered combination.The highest resistance was observed in penicillin(79.5%)and ampicillin(71.7%).The resistance rate of the isolates to cephalosporins,macrolide and tetracycline, fluoroquinolones and 3antibiotic combinations were approximately 60%,40%20%,and 10%respectively.None of isolates were resistant to vancomycin.The resistance to erythromycin of the isolates was mainly contributed by the ermC(46.4%)and ermB(37.5%)gene and ermAgene was not found in any isolates.TetK(70.0%)and tetM(10.0%)gene conferred the resistance of the isolates to tetracycline.Twenty-two CNS isolates were phenotypic and molecularly identified as MRS.The resistance rate of MRS isolates to penicillin(P<0.01),ampicillin(P<0.01),clarithromycin(P<0.01),erythromycin(P<0.01)and cefotaxime(P<0.05)were significantly higher than MSS.The results indicated that the prevalence of the superantigen genes in staphylococci isolated from bovine with clinical endometritis in Inner Mongolia was complicated and the antimicrobial resistance of the isolates was serious,meanwhile,the prevalence of MRCNS was observed in bovine originated staphylococcal isolates,suggesting that the resistance of the isolates to antimicrobial agents was one of the crucial reasons causing the failure of treatment for bovine clinical endomitritis in Inner Mongolia.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2014年第2期295-304,共10页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
基金
内蒙古自然科学基金重点项目(2009zd04)
关键词
奶牛子宫内膜炎
葡萄球菌
超抗原基因
耐药性
bovine endomitritis
Staphylococci
superantigen genes
antimicrobial resistance
