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目的研究蒙得维的亚沙门菌的耐药及分子流行病学特征。方法基于上海市针对人群和食源、环境沙门菌的监测基线,分析蒙得维的亚腹泻和食源环境株的耐药表型和分子型特征。结果蒙得维的亚在本地区的人源和食源沙门菌型数据库中列第24位(32株)和32位(13株)。经实验室确诊的28例蒙得维的亚病例均符合食源性感染特征,易感人群为5岁以下儿童和20~60岁男性,城郊地区高发。人源和食源株均发现对三代头孢(头孢他啶)耐药株,近5年中食源株的多重耐药(MDR)明显增多,28.1%的人源株对环丙沙星处于耐药临界值,来自境外动物制品的蒙得维的亚菌株对抗生素多数敏感。32株人源和13株食源株的分型聚类提示存在优势克隆簇,包括3起经回顾性鉴别诊断的蒙得维的亚的成人暴发,其中2起为多重耐药(MDR-ACSSuT)的克隆暴发。MDR-ACSSuT的人源流行株与甲鱼株之间存在高度的遗传同源性,与境外输入菌株间的耐药和分子型特征差异较大,2个不同克隆簇之间存在遗传进化关系。结论蒙得维的亚尚未在本地区成为优势种型,但其已通过贸易等方式不断输入国内,逐渐定殖于沿海地区的甲鱼养殖产业链和人群的消费食物链中,最终进化成稳定的MDR和非MDR克隆容易形成分散而隐蔽的食源性暴发。
Objective To study the drug resistance and molecular epidemiology of Salmonella typhi in Montevideo. Methods Based on the monitoring baseline of population and food-borne and environmental Salmonella in Shanghai, the drug resistance phenotypes and molecular characteristics of Montevideo diarrhea and food-derived environmental strains were analyzed. Results Montevideo ranked 24th (32) and 32 (13) in the human and food salmonella databases in the region. The 28 confirmed cases of Montevideo in the laboratory were all consistent with the characteristics of food-borne infections. The susceptible population was children under 5 years of age and men aged 20 to 60, with high incidence in suburban areas. Human and food-derived strains were found to be resistant to ceftazidime (Ceftazidime), with a significant increase in multidrug resistance (MDR) of food-derived strains in the past five years, with 28.1% of human strains being resistant to ciprofloxacin , Montevideo strains from overseas animal products are mostly susceptible to antibiotics. Phylogenetic clustering of 32 human and 13 food-derived strains suggested the presence of dominant clonal clusters, including 3 adult-onset adult outbreaks in Montevideo with a retrospective differential diagnosis, of which 2 were multidrug-resistant (MDR-ACSSuT ) Of clonal outbreaks. There was a high degree of genetic homology between the MDR-ACSSuT human-derived strain and the turtle strain, and there was a great difference between the imported strain and the imported strains. The two clonal clusters had a genetic evolutionary relationship. Conclusions Although Montevideo has not yet become the dominant species in the region, it has been continuously imported into the country through trade and gradually colonized the consumption food chain of the turtles in the coastal areas and the population, and finally evolved into a stable MDR And non-MDR clones tend to form scattered and subtle foodborne outbreaks.