肉鸡屠宰微环境中葡萄球菌耐药基因组件SCCmec的时空迁移机制研究

耐药性是评估肉源性葡萄球菌潜在致病性的重要指标。SCCmec作为葡萄球菌的典型移动基因组件，其在动物源环境中的分布已被广泛调查，然而SCCmec在特定环境中的转移规律鲜有关注和报道。申请人通过前期对鸡肉产品中葡萄球菌的污染调查，发现同来源鸡肉产品具有较高的葡萄球菌污染种类和污染水平相似性，肉鸡屠宰环境是产品葡萄球菌污染的主要直接来源。据此，本项目拟基于耐药基因组件SCCmec在葡萄球菌内的转移特征，对肉鸡屠宰环境中的SCCmec分布规律和转移机制进行研究。通过对关键肉鸡屠宰微环境的葡萄球菌进行分离鉴定，筛选SCCmec分子型和orfX下游的重复序列，应用多元生物信息分析和微环境模拟转移实验，分析验证肉鸡屠宰微环境中SCCmec的时空迁移机制，阐释SCCmec在特定环境中的进化和传播规律。通过本项目的实施，有助于揭示实际环境中耐药基因组件的转移机制，为食源性葡萄球菌耐药性的监控提供新思路。

Antibiotic resistance is an important index assessing the potential pathogenicity of meat-borne staphylococci. As a typical mobile genetic element in staphylococci, the disseminations of SCCmec in animal-origin environments have been extensively investigated, whereas, the transferring pattern of SCCmec specific environment is rarely concerned or reported. In our previous works, investigation of staphylococcal contamination in raw chicken meat products was performed, it showed that there is high similarity in staphylococcal species composition and cell number among same-sourced chicken meat products, which indicated that chicken slaughter environment is the main direct source causing staphylococci contamination for chicken meat products. In this program, based on the transferring characteristic of SCCmec in staphylococci, the dissemination pattern and transferring mechanism of SCCmec in chicken slaughter environments are studied. As for experiment design, staphylococci species are isolated and identified in chicken slaughter key microenvironments, molecular types of SCCmec and direct repeats in downstream of orfX are screened, with multi bioinformatics analysis and transferring experiment in simulated microenvironments, the time-space transferring mechanism of SCCmec in chicken slaughter microenvironments is observed, furthermore, the evolution and dissemination pattern of SCCmec in specific environments are revealed. With the implementation of this program, the transferring mechanism of antibiotic-resistant genetic element in practical environment is deeply discussed, which would provide a new insight for the surveillance of antibiotic resistance of food-borne staphylococci.