我国猪源甲氧西林耐药金黄色葡萄球菌的分子流行特征与传播机制研究

The high prevalence of Methicillin-resistant Staphylococcus aureus among hospital patients, community population and livestock has become a serious global issue for both clinical and public health. Livestock was considered a major reservoir for MRSA, especially the isolation rates of MRSA in swine is increasing in recent years. Through the contact transmission, the cross-species colonization and infection of porcine MRSA ST398 clone from swine to human has recently emerged in European countries and USA, suggesting the increase risks of public health, which quickly become a focus of concern and research hotspot. China has the biggest swine production in the world, although the high isolation rates of porcine MRSA was observed in recently years, the prevalence of ST9 clone in China is different from that in European countries and USA. However, we currently can not do the risk assessment of this epidemic clone and implement efficient control measures due to the lack of intensive investigation. This project is going to carrying out the research on porcine MRSA among typical breeding area in China by compressively applying the methods of microbiology, epidemiology, molecular biology, bioinformatics, and animal model etc. The aim of this project is to give an insight into the molecular epidemiology of porcine MRSA in China, elucidate the transmission routes and pollution mode of this microorganism, explicit the hazard characteristics of the epidemic clone in swine. This project will provide scientific basis for both risk assessment and containment of livestock LA-MRSA in China。

甲氧西林耐药金黄色葡萄球菌（MRSA）在医院病人、社区人群和养殖动物中广泛流行，已成为全球严峻的临床及公共卫生问题。动物是MRSA的重要贮库，近年来猪源MRSA的分离率不断上升，欧美地区猪群流行的MRSA克隆（ST398）开始出现通过接触传播跨宿主定植感染人的迹象，公共卫生风险凸显，成为了关注焦点和研究热点。作为世界第一养猪大国，我国猪源MRSA的分离率已较高，流行克隆（ST9）有别于欧美，但由于缺乏深入研究，目前仍不能评估其风险并制定有效控制措施。本项目拟综合应用微生物学、流行病学、分子生物学、生物信息学、动物模型等技术方法，对重点养殖区的猪源MRSA开展研究，旨在获得我国猪源MRSA的分子流行病学特征，探明猪源MRSA的传播途径与污染方式，明确我国猪源MRSA流行克隆的危害特征，为我国开展动物源MRSA的风险评估和控制提供科学依据。

项目背景：甲氧西林耐药金黄色葡萄球菌（MRSA）是国内外关注的几大超级细菌之一，近年来家畜相关MRSA尤其是猪源MRSA广泛流行，给公共卫生安全带来了威胁。我国是养猪大国，虽然猪源MRSA在不少地区已有检出报道，但对其流行与危害特征仍缺乏深入研究。.研究内容：本项目从我国几个重点养殖地区的代表性规模化养猪场、农户后院、屠宰厂、肉市场、城镇社区采集猪/猪肉、人和环境相关样品，分离鉴定金黄色葡萄球菌，通过表型检测、分子分型、全基因组序列分析等手段，阐明我国猪源MRSA的流行特征、传播途径与危害特征。.研究结果：（1）进一步明确了我国重点养殖区规模化养殖猪群MRSA的流行情况及分子流行特征；（2）首次调查掌握了我国农村后院散养猪群MRSA的流行情况及分子流行特征；（3）首次调查掌握了我国猪肉生产链MRSA的传播途径与污染特征；（4）从耐药表型、耐药和毒力基因型角度分析了我国猪源MRSA流行克隆的危害特征；（5）初步探明了我国猪源MRSA流行克隆的分子进化过程；（6）解析了猪源MRSA利福平耐药的分子机制；（7）从猪源MRSA中发现了新型伪SCCmec和新型多药耐药质粒；（8）探究了恶唑烷酮类耐药基因cfr、optrA在我国猪源葡萄球菌中的流行特征，特别发现cfr、optrA可整合到SCCmec元件随其传播。.科学意义：上述研究结果，有助于对我国猪源MRSA流行、传播与危害的深入了解与全面掌握，为开展动物源MRSA风险评估和控制提供充分的科学依据。