1、Department of Microbiology,Harbin Medical University肠杆菌科Enterobacteriaceae第十四章Department of Microbiology,Harbin Medical UniversityEnterobacteriaceaenA heterogeneous group of G-rods nTheir natural habitat is the intestinal tract of humans and animals(enteric bacilli)nFacultative anaerobes or aerobesu
2、Most are normal florauRegular pathogen for humans:Salmonella,Shigella,some E.colinMore than 30 genera,120 speciesDepartment of Microbiology,Harbin Medical UniversityDepartment of Microbiology,Harbin Medical University肠杆菌科细菌的生物学特征n 形态与结构u中等大小uG-杆菌u无芽胞u周鞭毛u菌毛n 培养u兼性厌氧或需氧u营养要求不高u菌落u混浊生长Department of Mi
3、crobiology,Harbin Medical University肠杆菌科细菌的生物学特征n生化反应：活泼u生化鉴定 (biochemical differentiation)u乳糖发酵致病菌：多不发酵乳糖非致病菌：多发酵乳糖n抗原结构Department of Microbiology,Harbin Medical University0.1%glucose1%lactose1%sucroseFerrous sulfatepH indicator:phenol redIdentificationnTriple sugar iron agar（TSI，三糖铁培养基）Department
4、of Microbiology,Harbin Medical UniversityTriple Sugar Iron AgarE.colimotile Lactose fermentedH2S-Shigella nonmotileLactose not fermentedH2S-Samonella motileLactose not fermentedH2S+Department of Microbiology,Harbin Medical University复杂的抗原构造n O（菌体）抗原uLipopolysacchriden H（鞭毛）抗原uFlagellan K 抗原u荚膜uVi 抗原
5、In Salmonella Typhi,the capsular antigen is called Vi antigenDepartment of Microbiology,Harbin Medical University抵抗力：不强易变异：多种引起通过接合转导融原性转换耐药性变异毒力性变异 生化反应性变异Department of Microbiology,Harbin Medical University埃希菌属 EscherichiaDepartment of Microbiology,Harbin Medical University 埃希氏菌属 （Escherichine）是人类
6、和动物肠道中的正常菌群群以大肠埃希氏菌（E.coli）最为重要要出生后数小时就进入肠道，并终生伴随随重要的实验材料和研究对象：在分子生物学和基因工程实验中大肠杆菌也是重要的实验材料和研究对象大肠杆菌也是重要的实验材料和研究对象Department of Microbiology,Harbin Medical University形态染色n0.4-0.7m 1-3m n短杆菌n革兰染色阴性n有鞭毛n有菌毛Department of Microbiology,Harbin Medical UniversityDepartment of Microbiology,Harbin Medical Uni
7、versity培养特性与生化反应n兼性厌氧n营养要求不高n生化反应活泼，发酵多种糖类n绝大多数发酵乳糖n典型E.coli:IMViC：+-Department of Microbiology,Harbin Medical University抗原结构nO抗原：菌体抗原,170种以上nH抗原：鞭毛抗原，56种以上nK抗原：荚膜抗原，100种以上nO111：K58：H2Department of Microbiology,Harbin Medical University致病物质n菌毛、定居因子nK抗原 u与侵袭力有关u抗吞噬与抗补体的溶菌n外毒素 u肠毒素及溶血毒素n内毒素u与感染特征和严重程度
8、有关Department of Microbiology,Harbin Medical University所致疾病n肠道外感染 u化脓性感染u泌尿道感染最多见 n腹泻Department of Microbiology,Harbin Medical University引起腹泻的大肠埃希菌n 肠产毒型大肠埃希菌 enterotoxigenic E.coli ETECn 肠侵袭型大肠埃希菌 enteroinvasive E.coli EIECn 肠致病型大肠埃希菌 enteropathogenic E.coli EPECn 肠出血型大肠埃希菌 enterohemorrhagic E.coli
9、EHECn 肠集聚型大肠埃希菌 enteroaggregative E.coli EAggECDepartment of Microbiology,Harbin Medical University肠产毒素型大肠埃希菌（ETEC）n致病物质u肠毒素（LT和ST）u菌毛粘附素（adhesin)u内毒素uK抗原n所致疾病u5岁以下婴幼儿腹泻u旅游者腹泻Department of Microbiology,Harbin Medical University肠侵袭型大肠埃希菌（EIEC）n 致病物质u不产肠毒素，侵袭结肠粘膜上皮细胞uShigelloid E.coli:EIEC无动力、生化反应和抗原结
10、构似Shigellan 所致疾病u主要侵犯较大儿童和成人u腹泻呈脓血便，有里急后重Department of Microbiology,Harbin Medical University 肠致病型大肠埃希菌（EPEC）n致病性u破坏刷状缘u不产生肠毒素及其他外毒素u无侵袭力n所致疾病u婴幼儿腹泻，热带国家、医院常流行u水性腹泻Gut lumenDepartment of Microbiology,Harbin Medical University肠出血型大肠埃希菌（EHEC）n vero毒素型大肠埃希菌 n 致病物质u菌毛：粘附作用u毒素：vero毒素n 所致疾病u出血性结肠炎u溶 血 性 尿
11、 毒 综 合 征（HUS）u5岁以下儿童易感，病情 不一轻重。u常见血清型为O157:H7Department of Microbiology,Harbin Medical UniversityThe“life cycle”of E.coli O157:H7Department of Microbiology,Harbin Medical UniversityE.coli O157:H7n 1982-first recognized as a pathogenn 1985-associated with hemolytic uremic syndromen 1990-outbreak from
12、 drinking watern 1991-outbreak from apple cidern 1993-multi-state outbreak from fast food hamburgersn 2019-outbreak from fresh producen 2019-outbreak in Japan -multi-state outbreak from unpasteurized apple juiceDepartment of Microbiology,Harbin Medical University肠集聚型大肠埃希菌 EAggECn致病物质u毒素u粘附素n所致疾病u引起婴
13、儿持续性腹泻，脱水，偶有血便Department of Microbiology,Harbin Medical UniversityDepartment of Microbiology,Harbin Medical University肺泡巨噬细胞吞噬大肠埃希菌免疫性 机体有一定免疫力，但不强可再感染。Department of Microbiology,Harbin Medical University 微生物学检查法n标本 n分离培养与鉴定u肠道外感染u肠道内感染 Department of Microbiology,Harbin Medical University微生物学检查法肠外感染
14、：标本分离培养涂片染色鉴定（生化反应（IMViC等）腹 泻：粪便鉴别培养基分离培养鉴定检测肠毒素毒力因子血清型Department of Microbiology,Harbin Medical University卫生细菌学检查n 大肠菌群数u每100(g)ml饮食样品中大肠菌群最近似数u大肠菌群：以E.coli为主，48小时内发酵乳糖产酸产气的革兰染色阴性的无芽胞需氧或兼性厌氧菌n 细菌总数 u每1ml(g)样品中细菌总数n 我国卫生标准u大肠菌群：每升水中3个以下，每100ml瓶装汽水、果汁等5个以下u细菌总数：每毫升饮用水不得超过100个Department of Microbiology,Harbin Medical University防治原则n疫苗n抗生素的抗性质粒，耐药性非常普遍Department of Microbiology,Harbin Medical University小结n肠道杆菌的共同特征及分类n致病性大肠埃希菌的种类和致病机制n大肠埃希菌的微生物学检查法n大肠埃希菌的卫生细菌学检查及其意义Department of Microbiology,Harbin Medical University问题n大肠埃希菌与人类健康的关系如何？n肠道杆菌的共同特征？n致人类腹泻大肠埃希菌有哪几种？
