Guo Dan, Liu Yangqun, Han Changlin, Chen Zhiyao, Ye Xiaohua
Laboratory of Molecular Epidemiology, School of Public Health, Guangdong Pharmaceutical University, Guangzhou, China,
Infect Drug Resist. 2018 Aug 23;11:1299-1307. doi: 10.2147/IDR.S173624. eCollection 2018.
Routine non-therapeutic antimicrobial use and overcrowding in animal farming may facilitate the propagation of methicillin-resistant (MRSA). This study aimed to examine the carriage prevalence and phenotype-genotype characteristics of MRSA and methicillin-susceptible isolated from pigs.
Nasal swabs were collected from 1,458 pigs in 9 pig farms and 3 slaughterhouses. All strains were tested for antimicrobial susceptibility, resistance genes, and virulence genes, and characterized by multilocus sequence typing. The correspondence analysis was conducted to explore the relationships between multiple phenotypic and molecular characteristics of isolates.
In the 1,458 pigs, the carriage prevalence was 9.5% for , 3.3% for MRSA, and 9.3% for multidrug-resistant . Notably, 97.1% isolates were multidrug resistant, and the predominant resistance pattern was non-susceptible to clindamycin, tetracycline, and erythromycin. The predominant genotype was CC9 (ST9) for and MRSA isolates. Importantly, all isolates were negative for the gene and resistant to tetracycline. Notably, all 9 linezolid-resistant isolates were classified as multidrug resistance, including 1 expressing the gene and 6 expressing the gene. The correspondence analysis showed a significant relationship between clonal complexes and resistance pattern or virulence genes. For example, CC9 was associated with extensive drug-resistance and co-carrying , , and , and CC1 was associated with multidrug resistance and co-carrying and .
The significant correspondence relationship between multiple characteristics provides some implication for vaccine strategies and new ideas for monitoring new epidemiologic clones.
动物养殖中常规的非治疗性抗菌药物使用和过度拥挤可能会促进耐甲氧西林金黄色葡萄球菌（MRSA）的传播。本研究旨在检测从猪中分离出的MRSA和甲氧西林敏感金黄色葡萄球菌的携带率及表型 - 基因型特征。
从9个养猪场和3个屠宰场的1458头猪中采集鼻拭子。对所有菌株进行抗菌药物敏感性、耐药基因和毒力基因检测，并通过多位点序列分型进行特征分析。进行对应分析以探讨分离株多种表型和分子特征之间的关系。
在1458头猪中，金黄色葡萄球菌的携带率为9.5%，MRSA为3.3%，多重耐药金黄色葡萄球菌为9.3%。值得注意的是，97.1%的金黄色葡萄球菌分离株具有多重耐药性，主要耐药模式为对克林霉素、四环素和红霉素不敏感。金黄色葡萄球菌和MRSA分离株的主要基因型为CC9（ST9）。重要的是，所有金黄色葡萄球菌分离株的mecA基因均为阴性且对四环素耐药。值得注意的是，所有9株耐利奈唑胺分离株均被归类为多重耐药，其中1株表达cfr基因，6株表达optrA基因。对应分析显示克隆复合体与耐药模式或毒力基因之间存在显著关系。例如，CC9与广泛耐药以及同时携带mefA、ermB和tetM相关，CC1与多重耐药以及同时携带mefA和ermB相关。
多种特征之间的显著对应关系为疫苗策略提供了一些启示，并为监测新的流行病学克隆提供了新思路。
