| 规模化畜禽养殖粪便中接合型耐药质粒污染及耐药基因赋存特征 |
| 摘要点击 861 全文点击 138 投稿时间：2024-01-28 修订日期：2024-04-20 |
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| 中文关键词 畜禽养殖 接合型质粒 抗生素耐药基因（ARGs） 表型 复制子 |
| 英文关键词 livestock breeding conjugative plasmids antibiotic resistance genes （ARGs） phenotypes replicon |
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| 中文摘要 |
| 近年来,细菌病原体中抗生素耐药性的出现和传播对公众健康构成严重的威胁. 为了解规模化养殖畜禽粪便中质粒介导的可移动抗生素耐药基因（ARGs）的赋存情况和转移特征,对北京、河北和宁夏等地区的蛋鸡、肉鸡和生猪规模化养殖场粪便进行耐药接合型质粒（CARP）的捕获与分析. 采用滤膜接合法对养殖场畜禽粪便中的CARP进行捕获并计算转移频率和流行率. 通过接合子基因组二代测序获得质粒携带ARGs信息,比对PlasimidFinder 数据库鉴定耐药质粒的复制子类型. 利用药敏纸片扩散法（Kirby-Bauer法）对接合子进行耐药表型测定. 结果表明,35个规模化养殖场捕获了125个CARP,共携带13类65种ARGs,最常见的ARGs为floR、aac（6′）-lb7和TEM-150. 不同养殖动物粪便中CARP流行情况有一定差异,其中蛋鸡粪中CARP具有更高的转移能力和流行率,但其多重耐药程度要弱于肉鸡和猪粪. 共检出49种共有的ARGs,其中64%属于氨基糖苷类、 β-内酰胺类、氟喹诺酮类和甲氧苄啶类. 64株典型接合子的耐药表型也有类似特点,主要对β-内酰胺类（95.31%）、四环素类（89.06%）、氨基糖苷类（87.5%）和氟喹诺酮类（68.75%）抗生素耐药率较高. 猪粪中检出IncH型、IncN型和IncR型这3种广宿主范围质粒,猪场中12.5% 接合子携带5个及以上高风险ARGs,比例高于其他养殖场. 研究表明,畜禽粪便中CARP普遍携带多种类型的ARGs,使宿主菌具有多种抗生素耐药能力；高风险ARGs被广宿主范围接合型质粒所携带,增加了其由养殖场向周边环境传播的风险. |
| 英文摘要 |
| The emergence and spread of antibiotic resistance in bacterial pathogens are now becoming a serious threat to public health globally. To study the occurrence and transfer characteristics of plasmid-mediated mobile antibiotic resistance genes （ARGs） in manure, antibiotic-resistant plasmids were captured from layers, broilers, and pig farms in Beijing, Hebei, and Ningxia provinces. The conjugative antibiotic-resistant plasmids （CARP） were captured by a filter membrane conjugation experiment, and the transfer frequency of plasmids from feces to recipient bacteria was tested. The ARGs-carried plasmid was extracted and sequenced with the Illumina sequencer, and the replicon types of CARP were identified with the PlasimidFinder database. The antibiotic-resistant phenotype of the captured conjugative plasmid was determined using the disk diffusion method （Kirby-Bauer）. In general, the 125 CARPs that were captured from 35 farms carried 13 types and 65 subtypes of ARGs. The most common ARGs were floR, aac （6'）-lb7, and TEM-150. Certain differences exist in the prevalence of CARP in the manure of different animals. The CARP in layer manure had a higher transfer frequency and prevalence than those in other animal farms, but the level of multidrug resistance conferred by these plasmids was lower than that of broilers and pigs. The 49 shared ARGs were observed from plasmids of broilers, layers, and pigs, of which 64% belonged to aminoglycosides, β-lactamase, fluoroquinolones, and trimethoprim-resistant genes. The antibiotic-resistant phenotypic characteristics of conjugants were similar with genotypes, and the dominant resistant conjugants belonged to β-lactamase （95.31%）, tetracyclines （89.06%）, aminoglycosides （87.5%）, and fluoroquinolones （68.75%）. IncH, IncN, and IncR plasmids were detected in pig manure, and 12.5% of the conjugants carried five or more high-risk ARGs in pig farms. The proportion of high-risk ARGs in pig farms was higher than that in other animal farms. In conclusion, the CARP in livestock manure commonly carries multiple types of ARGs, which can provide multiple antibiotic resistance capabilities for host bacteria. In addition, high-risk ARGs are carried by the broad host range of conjugative plasmids, which can promote the spread of high-risk ARGs in livestock farms to the surrounding environment. |
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