nature能在无生命培养基中繁殖的最小微生物ppt课件

1、Mycoplasmas 支原体A group of the smallest organisms that can be free-living in nature能在无生命培育基中繁衍的最小微生物Pass bacterial filter能经过0.45m滤菌器and also grow on laboratory media.Mollicute柔膜体纲Mycoplasmatales支原体目Mycoplasmataceae Acholeplasmataceae Spiroplasmataceae支原体科 无胆甾原体科 螺原体科支原体属 脲原体属Mycoplasma genera Ureplas

2、ma generaClassification .生物学性状没有细胞壁的原核细胞型微生物多形性：球形，双球状，丝状,特殊构造：荚膜，顶端构造，微丝细胞膜含固醇大小，0.20.3m繁衍方式：二分裂繁衍，出芽等含DNA与RNA染色方法： Giemsa染色 淡紫色 革兰染色阴性.Mycoplasma and L Form BacteriaMYCOPLASMAL-FORM BACTERIANo genetic relationship with bacteriaRelate to their parent bacteria ,sometimes can revertCholesterol for th

3、eir cell membrane No cholesterol for their cell membraneStable in ordinary mediumNeed hyperosmotic solutionGrow slowly, colony small (diameter 0.1-0.3mm)Colony larger(diameter 0.5-1.0mm)Low turbidity in liquid mediumHigh turbidity in liquid medium ,may adhere to the wall or bottom of the tube.三、支原体与

4、细菌L型的区别 支原体 L型 在遗传上与细菌无关 与原菌相关，常可以回复 细胞膜含高浓度固醇 细胞膜不含固醇 在普通培育基中稳定 大多需高渗培育 生长慢，菌落小， 菌落稍大， 液体培育混浊度极低 液体培育有一定混浊度.肺炎支原体人型支原体生殖器支原体穿透支原体溶脲脲原体.培育营养要求pH：低于7.0那么死亡溶脲脲原体pH6.06.5生长缓慢典型的菌落呈荷包蛋样 “T株液体培育基不易见到混浊细胞培育污染的重要要素.Resistance Sensitive to osmotic pressure浸透压resistant to thallium acetate醋酸亚铊in a concentrati

5、on of 1:10000 which can inhibit bacteria对青霉素等耐药对干扰蛋白质合成抗生素敏感.TransmissionM. pneumoniae is spread by close contact via aerosolized droplets and thus is most easily spread in confined populations (e.g., families, schools, army barracks). .PATHOGENESIS Adherence factors - The P1 Adhesin localizes at ti

6、ps of the bacterial cells and binds to sialic acid residues on host epithelial cells.The nature of the adhesins in the other species has not been established. Colonization of the respiratory tract by M. pneumoniae results in the cessation of ciliary movement. Toxic Metabolic Products Immunopathogene

7、sis : most children are infected from 2 - 5 years of age but disease is most common in children 5-15 years of age.M.pneumoniaeprimary atypical pneumonia. Incubation: 1-3 weeksThis disease can range from subclinical to bronchopneumonia, often with a gradual onset and mild to moderate severity. A long

8、 convalescence (4-6 weeks) and several possible complications (CNS, cardiac) follow acute disease. .主要致病性支原体一、肺炎支原体 原发性非典型肺炎primary atypical pneumonia 间质性肺炎占非细菌性肺炎的二分之一飞沫传播，夏末秋初为好发季节病症较轻，发热、咳嗽、有时有呼吸道外并发症气管上皮纤毛.Clinical FindingsU. urealyticum, M.hominis, M.genitalium are responsible for one form of n

9、ongonococcal urethritis. M. hominis is associated with pyelonephritis肾盂肾炎, pelvic inflammatory disease 盆腔疾病. .HOST DEFENSES Host defenses are not well characterized but probably involve both humoral and cell mediated responses. . EPIDEMIOLOGY Mycoplasma affect a specific age distribution (5-9 year o

10、lds) and represent 8-15% of all pneumonias in school age children. Disease occurs worldwide, is endemic in some areas and is spread by close personal contact (schools, families). U. urealyticum is sexually acquired. .Antibody titers in different age groups. Anti-mycoplasma pneumoniae antibodies indi

11、cate pneumonia caused by this organism is highest in the 5-15 year age group .Acquired Pneumonia Caused by Mycoplasma pneumoniae .Microbiological diagnosis Specimens: throat swab, sputum, genital secretion, etc.Microscopy - This is not particularly useful because of the absence of a cell wall but it

12、 can be helpful in eliminating other possible pathogens.Culture - Sputum (usually scant) or throat washings must be sent to the laboratory in special transport medium. It may take 2 -3 weeks to get a positive identification. Culture is essential for a definitive diagnosis.Complement fixation test Co

13、ld agglutinins - Approximately 34% - 68% of patients with M. pneumoniae infection develop cold agglutinins. ELISA - There is a new ELISA for IgM that has been used for diagnosis of acute infection. PCR.代谢抑制实验MIT 血清抗体生长抑制实验GIT.CONTROLSanitary: Avoidance of contacts, if possible.Immunological: No sing

14、le vaccine is available. Natural resistance follows infection.Chemotherapeutic: Tetracycline, erythromycin or chloramphenicol are effective. .More than 80 species, belong to Mycoplasmatales of Mollicute. 3 families can be divided: Mycoplasmataceae (require external cholesterol during growth, contain

15、 Mycoplasma and Ureplasma two genera); Acholeplasmataceae (need not external cholesterol during growth); Spiroplasmataceae (can form spiral structure) .生化反响 人类主要支原体生物学性状支原体 葡萄糖 精氨酸 尿素 致病性 肺炎支原体 + 肺炎、支气管炎人型支原体 + 泌尿生殖道感染生殖器支原体 + 泌尿生殖道感染穿透支原体 + + 多见于艾滋病溶脲脲原体 + 泌尿生殖道感染 .解脲支原体M.urealyticum脲原体属中独一的一个种，因生长

16、需求尿素而得名。分解尿素为其代谢特征，产生氨氮，使培育基pH上升，患者小便往往带有臊腥味。 菌落微小，直径仅有1525um，须在低倍显微镜下察看，称T株 (tiny strain)。菌落外表有粗糙颗粒，在适宜条件下可转成典型的荷包蛋样菌落。.解脲支原体与女性生殖安康关系最为亲密,解脲支原体可引起泌尿生殖道感染，并被以为是非淋球菌性尿道炎中仅次于衣原体占50%的重要病原体。由于80%孕妇的生殖道内带有解脲脲原体，因此可经过胎盘感染胎儿而导致早产、死胎，或在分娩时感染新生儿，引起呼吸道感染。此外，解脲脲原体还可引起不孕症。.解脲支原体感染主要经过性生活传播，多见于年轻性旺盛时期，尤多见于不洁性交后

17、。当泌尿生殖道发生炎症，粘膜外表受损时解脲支原体易从破损口侵入，引起泌尿生殖道感染。患者大多无明显病症，也易呵斥医生漏诊。解脲支原体可引起尿道炎、宫颈炎与前庭大腺炎；上行感染时，可引起子宫内膜炎、盆腔炎、输卵管炎，尤其输卵管炎多见。.二、致病性与免疫性致病性 支原体 致病性 肺炎支原体 原发性非典型肺炎、支气管炎 外表感染人型支原体 泌尿生殖道感染 外表感染生殖器支原体 泌尿生殖道感染 外表感染穿透支原体 多见于艾滋病 入血溶脲脲原体 泌尿生殖道感染 外表感染.致病性构成细胞损伤获得养料产生有毒代谢产物免疫损伤.三、穿透支原体穿透支原体是1990年初次从1例HIV阳性艾滋病患者尿中分别出的一种

18、新支原体 穿透支原体的致病性与其尖形构造有关，具粘附和穿入作用，引起细胞损伤 穿透支原体感染 是艾滋病的辅助致病要素 .第一节衣原体衣原体Chlamydia是一类在真核细胞内寄生、有独特发育周期、能经过滤菌器的原核细胞型微生物。衣原体的特征是：严厉的真核细胞内寄生，具有独特的发育周期，以二分裂方式繁衍；革兰染色阴性，球形，也可呈椭圆形；具有与革兰阴性菌类似的细胞壁；含有核糖体，能进展多种代谢，因缺乏供代谢所需的能量来源，故表现为严厉的细胞内寄生；有DNA和RNA两种类型的核酸；对多种抗生素敏感，特别是对四环素和红霉素敏感。.发育周期衣原体在宿主细胞内增殖，具有独特的发育周期。用普通光学显微镜可

19、察看到两种大小、形状构造不同的颗粒。.原体elementary body, EB始体(initial body)原体：位于细胞外，球形，小而致密，有感染性。始体：位于细胞内，大而疏松,纤细网状构造，也称网状体reticulate body, RB， 无感染性。 .衣原体分类衣原体广泛寄生于人、哺乳动物及禽类体内，仅少数有致病性。根据衣原体抗原构造、包涵体的性质、DNA的同源性及对磺胺敏感性等的不同，将衣原体属Chlamydiae分为四个种，即沙眼衣原体C. trachomatis沙眼生物亚种(Biovar trachoma)、性病淋巴肉芽肿Biovar lymphogranuloma venereum LGV生物亚种和鼠生物亚种(Biovar mouse)鹦鹉热衣原体(C. psittaci)肺炎衣原体(C. pneumonia)兽类衣原体C. pecorum。主要对人致病的衣原体沙眼衣原体最多见。.致病性和免疫性内毒素类似的致病物质。衣原体入侵在宿主细胞中大量繁衍，抑制细胞代谢，致使细胞溶解； 衣原体尚可引起超敏反响和构成肉芽肿。主要的传播途径：眼-眼、眼-手