苯唑西林敏感、mecA基因阳性的猪源金黄色葡萄球菌的流行、分子分型及耐药性研究  

Molecular typing and antimicrobial susceptibility of oxacillinsusceptible,mecA-positive Staphylococcus aureus from pigs

作　　者：张鹏飞 寇明莹 张强[1] 张萌 徐旭 张钰嘉 王婷[1] 杨雪微 吴聪明[2] 王新[1] Pengfei Zhang;Mingying Kou;Qiang Zhang;Meng Zhang;Xu Xu;Yujia Zhang;Ting Wang;Xuewei Yang;Congming Wu;Xin Wang(College of Food Science and Engineering,Northwest A&F University,Yangling 712100,Shaanxi Province,China;College of Veterinary Medicine,China Agricultural University,Beijing 100193,China)

机构地区：[1]西北农林科技大学食品科学与工程学院,陕西杨凌712100 [2]中国农业大学动物医学院,北京100193

出　　处：《微生物学报》2021年第11期3607-3618,共12页Acta Microbiologica Sinica

基　　金：国家自然科学基金(31871894,U1703119,31271858)。

摘　　要：【目的】为了解我国猪源苯唑西林敏感-mecA阳性金黄色葡萄球菌(Oxacillin-susceptible,mecA-positive Staphylococcus aureus,OS-MRSA)的流行情况、菌株分子特征及耐药性,本研究对我国中西部4个省份(甘肃、陕西、河南和广西)的9个规模化养猪场进行鼻腔拭子样本采集。【方法】运用PCR扩增nuc和mecA基因及苯唑西林耐药性检测对OS-MRSA菌株进行分离鉴定。然后对分离所得的OS-MRSA菌株进行26种毒素编码基因、16种抗生素耐药性以及spa、MLST和SCCmec分型检测。【结果】结果表明,采集的884份样本中,67份样本7.6%(67/884)分离到金黄色葡萄球菌,包括50株甲氧西林敏感菌株(Methicillin-sensitive Staphylococcus aureus,MSSA)、8株苯唑西林耐受-mecA阳性金黄色葡萄球菌(Oxacillin-resistant mecA-positive,OR-MRSA)和9株OS-MRSA菌株。26种被检毒素编码基因中有9种毒素编码基因被检出,其中hla基因检出率最高,其次为hld、hlb、hlg、sei、sem、seg、sen和seo。此外,67株分离株中仅有16株携带肠毒素编码基因,其中OR-MRSA和OS-MRSA菌株分别占37.5%(6/16)和50.0%(8/16),且携带毒素编码基因的菌株克隆型均为ST9-t899。16种所测试抗生素中,菌株对12种抗生素表现为耐药,其中MSSA、OR-MRSA和OS-MRSA分离株分别主要对1–8、10–12和7–11种抗生素耐药。所有分离株共有4种克隆型ST398-t571、ST9-t899、ST398-t034和t11241,其中ST9-t899为MRSA菌株唯一克隆型和ST398-t571为MSSA优势克隆型。除4株分离株未检测到SCCmec分型外,IVb(76.5%,13/17)是MRSA分离株的唯一分型。【结论】结果表明,我国猪源MRSA分离株对苯唑西林药物敏感性发生了改变,出现了较多的苯唑西林敏感菌株。此外,MSSA和MRSA分离株优势克隆型分别为ST398-t571和ST9-IVb-t899。研究还发现,克隆型与毒素编码基因有显著相关性,携带毒素编码基因的菌株克隆型均为ST9-t899。通过了解我国猪源MSSA、OR-MRSA和OS-MRSA的流行、[Objective]To investigate the prevalence,molecular characteristics and antibiotic resistance of oxacillin-susceptible,mecA-positive Staphylococcus aureus(OS-MRSA)isolates from pigs,we collected samples from 9 large-scale pig farms in four central and western provinces of China(Gansu,Shaanxi,Henan and Guangxi).[Methods]The OS-MRSA isolates were identified by amplifying nuc and mecA gene and oxacillin susceptibility tests.Twenty-six toxin-encoding genes,16 kinds of commonly used antibiotic resistance and molecular typing(spa,MLST and SCCmec)of the isolates were detected.[Results]The results showed that 67(7.6%,67/884)of the 884 samples were contaminated with S.aureus.A total of 67 isolates were isolated,including 50 isolates of methicillin-susceptible Staphylococcus aureus(MSSA),8 isolates of oxacillin-resistant mecA-positive(OR-MRSA)and 9 isolates of OS-MRSA.Among the 26 toxin-encoding genes,9 toxin-encoding genes were detected,and the hla gene had the highest detection rate,followed by hld,hlb,hlg,sei,sem,seg,sen and seo.Sixteen isolates that carrying the enterotoxin-encoding genes,OR-MRSA and OS-MRSA isolates accounted for 37.5%(6/16)and 50.0%(8/16),respectively.The isolates carrying the enterotoxin-encoding genes were all ST9-t899 clone type.Among the 16 antibiotics tested,the isolates were resistant to 12 antibiotics,among which MSSA,OR-MRSA and OS-MRSA isolates were mainly resistant to 1–8,10–12 and 7–11 antibacterial drugs,respectively.Four clone types(ST398-t571,ST9-t899,ST398-t034 and t11241)were identified,among which ST9-t899 was the only clone type of MRSA and ST398-t571 was the dominant clone type of MSSA.With the exception of four isolates where SCCmec typing was not detected,IVb(76.5%,13/17)was the only type in MRSA isolates.[Conclusion]To sum up,the sensitivity of pig MRSA isolates to oxacillin had changed,and they were generally sensitive to oxacillin.In addition,the dominant clone types of MSSA and MRSA strains were ST398-t571 and ST9-t899,respectively.The study also found that the clone typ

关 键 词：OS-MRSA 毒素编码基因 耐药性 分子分型 

分 类 号：S858.28[农业科学—临床兽医学]