酱卤肉制品中可移动遗传元件介导的功能基因水平转移风险

Risk assessment of horizontal gene transfer mediated by mobile genetic elements in sauced meat products

中文关键词:  酱卤肉制品  可移动遗传元件  水平基因转移  耐药基因  宏基因组  肉源差异

英文关键词:sauced meat products  mobile genetic elements  horizontal gene transfer  antimicrobial resistance gene  metagenomics

中文摘要:

      目的 阐明酱卤肉制品中可移动遗传元件(mobile genetic elements, MGEss)的肉品类型依赖性分布规律。方法 采集5个品牌20份样品(牛肉、猪肉、鸡肉、鸭肉各5份), 宏基因组测序结合mobileOG数据库分析MGEss组成、宿主来源及携带的耐药基因和毒力因子。结果 共注释到2180个非冗余MGEs基因, 酱卤猪肉中MGEs丰富度最高(1789个, 其中960个为猪肉独有), 鸭肉最低; 4组间存在1557个跨组共享基因及94个核心MGEs基因。功能层面以“复制/重组/修复”类为主(40.6%), 猪肉中“整合/切除”(62.6%)与“转移”(52.3%)功能显著富集; 接合转移(Tra)家族、整合酶及转座酶在猪肉中分别为其他肉品的3.9~31.8倍, 提示猪肉基质中MGEs介导的基因组重排与水平迁移活性最强。毒素-抗毒素系统呈明显肉品选择性, Ccd系统仅见于鸡肉和猪肉。微生物溯源表明, 肠球菌属、乳杆菌属和柠檬酸杆菌属是驱动MGEs多样性的核心菌群; 猪肉P004中存在接合转移相关MGEs共现簇, P002中存在乳酸菌相关MGEs共现簇, 说明存在耐药基因水平转移及发酵工艺输入的潜在风险。结论 酱卤肉制品中MGEs分布呈显著肉品类型依赖性, 猪肉基质中水平基因转移活性最强, 肠球菌属等为核心驱动菌群; 发酵工艺可能引入乳酸菌相关MGEs并增加耐药基因转移风险。

英文摘要:

      Objective To clarify the meat type dependent distribution pattern of mobile genetic elements (MGEss) in sauced meat products. Methods A total of 20 samples from 5 brands were collected, including 5 samples each of beef, pork, chicken and duck. Metagenomic sequencing was performed, and the mobileOG database was employed to analyze MGEs composition, host sources and associated antimicrobial resistance genes and virulence factors. Results A total of 2180 non-redundant MGEs genes were annotated. Braised pork exhibited the highest MGEs richness (1789 genes, of which 960 were pork-specific), while duck showed the lowest. Across the 4 groups, 1557 cross-group shared genes and 94 core MGEs genes were identified. Functionally, “replication/recombination/repair” genes predominated (40.6%). Pork showed significant enrichment in “integration/excision” (62.6%) and “transfer” (52.3%) functions. The expression levels of conjugative transfer (Tra) family genes, integrases and transposases in pork were 3.9–31.8-fold higher than those in other meat types, indicating the strongest MGEs-mediated genomic rearrangement and horizontal transfer activity in pork matrices. Toxin-antitoxin systems exhibited marked meat-type selectivity, with the Ccd system detected exclusively in chicken and pork. Microbial source tracking revealed that Enterococcus, Lactobacillus and Citrobacter were the core bacterial taxa driving MGEs diversity. Co-occurrence clusters of conjugative transfer-related MGEss were identified in pork sample P004, while Lactobacillus-associated MGEs co-occurrence clusters were found in P002, suggesting potential risks of antimicrobial resistance gene horizontal transfer and starter culture contamination during fermentation processing. Conclusion The distribution of MGEs in sauced meat products exhibits significant meat-type dependency, with the highest horizontal gene transfer activity observed in the pork matrix and Enterococcus spp. identified as the core driving microbiota; fermentation processes may introduce lactic acid bacteria-associated MGEs, thereby increasing the risk of antimicrobial resistance gene transfer.