人卫7微生物chapter9球菌

1、Staphylococcus (gram-positive) E. coli (gram-negative) Categories of cocci 1. Staphylococcus（葡萄球菌属） 2. Streptococcus（链球菌属） 3. Neisseria（奈瑟菌属） Section 1 Staphylococcus（球菌属）（球菌属） 1. Staphylococcus aureus（金黄色葡萄球菌）（金黄色葡萄球菌） I. Biological characterization II. Pathogenesis and symptomatology III. Laborato

2、ry diagnosis IV.Epidemiology, treatment and control 2. Staphylococcus epidermidis（表皮葡萄球菌）（表皮葡萄球菌） 3. Staphylococcus saprophyticus（腐生葡萄球菌）（腐生葡萄球菌） Biological characterization A. Morphology: Gram-positive spherical cells arranged in grape- like clusters. Lack spore and flagella B. Culture characterist

3、ics: Colonies: round, smooth, raised, glistening Pigments: fat soluble; golden yellow (pathogenic), white or lemon Blood agar plate: -hemolysis (pathogenic) C.Biochemical reactions Catalase（触酶）test: + D.Antigens SPA Capsular polysaccharide Other polysaccharides E.Classification Staphylococcus aureus

4、（金黄色葡萄球菌） Staphylococcus epidermidis（表皮葡萄球菌） Staphylococcus saprophyticus（腐生葡萄球菌） F.Resistance: relatively strong, resistant to many antibiotics S. aureus morphology S. aureus morphology Staphylococcus colonies on common agar plate Pigments S. aureus ( golden yellow) S. epidermidis (white) S. saprop

5、hyticus (lemon) Blood agar plate, S. aureus 11 hemolysis Catalase test SPA 葡萄球菌葡萄球菌A蛋白蛋白 Staphylococcal Protein A Definition: A cell wall component of many S. aureus strains that binds to the Fc portion of IgG molecules except IgG3. In vitro, SPA has become an important reagent in immunology and dia

6、gnostic laboratory technology. In vivo, SPA can effectively diminish opsonization. IgGIgG FcFc SPASPA Staphylococcus IgG Fc receptorIgG Fc receptor macrophagemacrophage Anti-phagocytosis（抗吞噬）（抗吞噬） Coagglutination test（协同凝集试验）（协同凝集试验） FabFab SPA bind to IgG Fc AntigenStaphylococcus aggregation Pathog

7、enesis and symptomatology Pathogenic substances I.Enzymes II.Toxins III.Surface structure proteins 1.Adhesin（黏附素） 2.Capsule（荚膜） 3.Peptidoglycan（肽聚糖） 4.SPA Enzymes 1.Coagulase（凝固酶） 2.Other enzymes Fibrinolysin（纤维蛋白溶酶） Hyaluronidase（透明质酸酶） Heat-stable nuclease（耐热核酸酶） Lipase（脂酶） Toxins 1.Staphylolysin

8、（葡萄球菌溶素） 2.Leukocidin（杀白细胞素） 3.Enterotoxin（肠毒素） 4.Exfoliative toxin（表皮剥脱毒素） 5.TSST-1（毒性休克综合征毒素-1） Coagulase（凝固酶）（凝固酶） An enzyme-like protein produced by S. aureus that clots oxalated or citrated plasma. Its production is considered as invasive pathogenic potential. Two types: Free coagulase（游离凝固酶） B

9、ound coagulase（结合凝固酶） S. aureus coagulase test Positive Negative 凝固酶的作用凝固酶的作用 保护作用：保护作用：抗吞噬，抗杀菌物质抗吞噬，抗杀菌物质 感染感染病灶的病理特性：病灶的病理特性：局限化局限化、脓汁粘稠、脓汁粘稠 和形成血栓和形成血栓 具有免疫原性具有免疫原性 Staphylolysin（葡萄球菌溶素）（葡萄球菌溶素） ,-toxins Cytotoxin. It is a potent hemolysin (溶血素). Acts on a broad spectrum of eukaryotic cell membra

10、nes. (RBCs, WBCs, platelets, hepatocytes, etc.) Leukocidin（杀白细胞素）（杀白细胞素） Cytotoxin. Damage the cell membranes of neutrophils and macrophages. Inhibit phagocytosis and aggravate tissue damage. Enterotoxin（肠毒素）（肠毒素） It is a group of soluble and heat-stable proteins. Resistant to the action of gut enzy

11、mes. An important cause of food poisoning (食物中毒). Ingestion of enerotoxin results in vomiting (呕吐) and diarrhea. It is an superantigen. 食物中毒食物中毒 呕吐为主要症状呕吐为主要症状 Exfoliative toxin（表皮剥脱毒素）（表皮剥脱毒素） Epidermolytic toxins (表皮溶解毒素) The epidermolytic toxins yield the generalized desquamation of the straphylo

12、coccal scalded skin syndrome（烫伤样皮肤综合征，SSSS）. Toxic shock syndrome toxin-1 毒性休克综合征毒素-1 An superantigen. Causes toxic shock syndrome（TSS，毒性休 克综合征） Associated with fever, shock, and multisystem involvement. Clinical findings I.Invasive diseases (pyogenic infection) Skin lesions: furuncle (疖), carbuncle

13、 (痈), impetigo (脓疮) Deep lesions: infections of bones, joints, deep organs, and soft tissues. Systemic infections: septicemia and pyemia II.Toxin-mediated diseases Staphylococcal food poisoning（食物中毒） Scalded skin syndrome (SSS)（烫伤样皮肤综合征） Toxic shock syndrome (TSS)（毒性休克综合征） Cutaneous lesions of S. au

14、reus Boil（疖） Laboratory Diagnosis Gram stain: Gram-positive cocci in clusters Golden yellow pigment Catalase tests Coagulase tests Antibiotic susceptibility tests Blood cultures Identification of the pathogenic staphylococcus 金黄色色素（金黄色色素（+） 溶血性（溶血性（+） 凝固酶（凝固酶（+） 耐热核酸酶（耐热核酸酶（+） 发酵甘露醇（发酵甘露醇（+） Antibio

15、tic susceptibility tests Section 2 Streptococcus Classification of Streptococci 1. Based on the cell wall antigens AH.KV 20 groups 90% pathogenic strains belong to group A 2. Based on the hemolysis reactions hemolysis S. pneumoniae and others -hemolysis group A, B, C, G and some D strains -hemolysis

16、 Hemolysis Classification based on hemolysis 细菌类别别名溶血环溶血类型致病性 甲型溶血甲型溶血 性链球菌性链球菌 草绿色链草绿色链 球菌球菌 12mm 草绿色草绿色 甲型溶血甲型溶血 / 溶血溶血 机会性致机会性致 病菌病菌 乙型溶血乙型溶血 性链球菌性链球菌 溶血性链溶血性链 球菌球菌 24mm 全透明无色全透明无色 乙型溶血乙型溶血 / 溶血溶血 致病力强致病力强 丙型溶血丙型溶血 性链球菌性链球菌 不溶血性不溶血性 链球菌链球菌 无无不溶血不溶血一般不致一般不致 病病 Group A streptococcus（A群链球菌）群链球菌） I.B

17、iological characterization II.Pathogenesis and symptomatology III.Laboratory diagnosis IV. Epidemiology, treatment and control Biological characterization A.Morphology: Gram-positive spherical/ovoid cocci arranged in long chains. Non-spore-forming, nonmotile Can form capsules and pili B.Culture char

18、acteristics: Facultative anaerobes (兼性厌氧) Most are fastidious and require enriched media (营养要求 较高). Colonies: small, round, smooth, nonpigmented Blood agar plate: -hemolysis (pathogenic) C.Biochemical reactions Catalase（触酶）test: - D.Antigens Polysaccharide antigen (Antigen C) Group specific antigen（

19、群特异性抗原）. Majority of human pathogenic streptococci are group A. Protein antigen Type specific antigen（型特异性抗原） Protein M is a major virulence factor. Nucleoprotein antigen (Antigen P): nonspecific F.Resistance: Sensitive to drying, heat, and disinfectants Streptococcus Streptococcus Hemolysis pattern

20、s hemolysis hemolysis no hemolysis hemolysis Streptococcus Pathogenesis and symptomatology Pathogenic substances I.Cell wall components Adhesin（黏附素）（黏附素）: LTA & protein F Protein M Peptidoglycan（肽聚糖）（肽聚糖） II.Exotoxins Pyrogenic exotoxin（致热外毒素）（致热外毒素） Streptolysin（链球菌溶素）（链球菌溶素） III.Invasive enzymes H

21、yaluronidase（透明质酸酶）（透明质酸酶） Streptokinase（链激酶）（链激酶） Streptodonase（链道酶）（链道酶） Adhesin（黏附素）（黏附素） Lipoteichoic acid (LTA, 脂磷壁酸) Protein F (F蛋白) Bind to the corresponding receptors on host cells and facilitate the adherence. Protein M（M蛋白）蛋白） A major virulence factor of group A streptococci. Facilitates t

22、he adherence. Inhibits phagocytosis and killing of immune cells. A common antigen (共同抗原). Contributes to some hypersensitivity diseases. View of group A Streptococcus 54 Peptidoglycan（肽聚糖）（肽聚糖） Pyrogenic Damages platelets Increases vascular permeability Induces experimental arthritis Pyrogenic exoto

23、xin 致热外毒素、红疹毒素、猩红热毒素 Is associated with streptococcal toxic shock syndrome （链球菌毒性休克综合征）and scarlet fever（猩红热）. Pyrogenic Highly antigenic. Acts as an superantigen. Streptolysin（链球菌溶素）（链球菌溶素） 1. Streptolysin O (SLO, 链球菌溶素链球菌溶素O) Oxygen-labile (SH groups) Rapidly inactivated in the presence of oxygen

24、Highly antigenic Antistreptolysin O test (ASO test) 2. Streptolysin S (SLS, 链球菌溶素链球菌溶素S) Oxygen-stable Not antigenic. -hemolysis on blood agar plates. both cause cell and tissue injury Damage RBCs, WBCs and platelets. Hyaluronidase （透明质酸酶）（透明质酸酶） Splits hyaluronic acid（透明质酸）, an important component

25、of the ground substance of connective tissue. Aids in spreading infecting microorganisms. Spreading factor（扩散因子）. Streptokinase（SK） 链激酶 Streptococal fibrinolysase（链球菌溶纤维蛋白酶） It transforms the plasminogen (纤维蛋白酶原) of human plasma into plasmin (纤维蛋白酶), an active proteolytic enzyme that digests fibrin

26、(纤维蛋白) and other proteins. Spreading factor（扩散因子） Streptodonase（SD） 链道酶 Streptococal deoxyribonuclease（链球菌DNA酶） Depolymerizes DNA. Spreading factor（扩散因子） 链球菌感染病灶特点：链球菌感染病灶特点： 脓汁稀薄，病灶扩散，边界不清脓汁稀薄，病灶扩散，边界不清 Clinical findings I.Pyogenic infections Infections of skin and subcutaneous tissues Infections o

27、f other tissues: tonsillitis, pharyngitis, tympanitis, etc. II.Toxin-mediated diseases Scarlet fever（猩红热） Streptococcal toxic shock syndrome （链球菌毒性休克综合征） III.Allergic diseases Acute rheumatic fever (ARF)（风湿热） Acute glomerulonephritis（急性肾小球肾炎） Streptococcal skin infections Pharyngitis（咽炎）and tonsilli

28、tis（扁桃体炎） Streptococcal sore throat（咽炎） Scarlet fever Laboratory diagnosis Laboratory diagnosis Specimens（标本采集）: To be obtained depend upon the nature of the straptococcal infection. Smears（涂片）: G+, spherical/ovoid cocci, arranged in long chains. Culture: blood agar plates (hemolysis) Serological te

29、sts: ASO test ASO test 抗链球菌溶素O试验 Antistreptolysin O test is a measure of the blood plasma levels of antistreptolysin O antibodies used in tests for the diagnosis of a streptococcal infection or indicate a past exposure to streptococci. It is used to help diagnose post-streptococcal sequelae of rheum

30、atic fever (风湿热) and glomerulonephritis (肾小球肾炎). Streptococcus phenumoniae（肺炎链球菌）（肺炎链球菌） I.Biological characterization II.Pathogenesis and symptomatology III.Laboratory diagnosis IV. Epidemiology, treatment and control Biological characterization A. Morphology: Gram-positive, lancet-shaped diplococc

31、i Non-spore-forming, nonmotile Can form capsules B. Culture characteristics: Facultative anaerobes (兼性厌氧) Most are fastidious and require enriched media Colonies: small, round, smooth Blood agar plate: -hemolysis Autolysis (自溶现象) C. Biochemical reactions Bile bacteriolysis test: + D. Resistance: Sen

32、sitive to drying, heat, and disinfectants left： hemolytic streptococcus negative（turbidity） right： S. Pneumoniae positive（clear、transparent） Capsule S. Pneumoniae S. Pneumoniae Capsule S. Pneumoniae S. Pneumoniae in sputum（Gram stain,1000） S. Pneumoniae , blood agar plate（hemolysis） Pathogenicity Pa

33、thogenic substances 1.Capsule 2.Pneumolysin O 3.Lipoteichoic acid 4.Neuraminidase Clinical findings 1.Pneumococcal pneumonia 2.Pneumococcal meningitis 3.Other complications Laboratory diagnosis 1.Smears 2.Cultivation 3.Distinguished from viridans (草绿色) streptococci -hemolytic Bile solubility Optochi

34、n sensitivity Inulin (菊糖) fermentation Quelling reaction Animal toxic experiment Neisseria（奈瑟菌属）（奈瑟菌属） Gram-negative cocci Pairs Pathogenic for humans: Neisseria meningitidis （脑膜炎奈瑟菌） Neisseria gonorrhoeae （淋病奈瑟菌） Neisseria Meningitidis (脑膜炎奈瑟菌脑膜炎奈瑟菌) Biological characterization A. Morphology: Gram-

35、negative, kidney-shaped diplococci Can form capsules and pili B. Culture characteristics: Enriched media: modified Thayer-Martin medium Colonies: convex, glistening, elevated, mucoid Autolysis (自溶现象) C. Resistance: weak 露滴状菌落 Pathogenicity Pathogenic substances Capsule Adhesive fimbriae IgA protease

36、 Lipooligosaccharide (LOS) Epidemic meningitis 流行性脑脊髓膜炎 Nature hosts: humans (only) Portal of entry: the nasopharynx 普通型 爆发型 败血症型 Petechiae in epidemic meningitis Clinical Diagnosis Gram stain: CSF, blood, or nasopharyngeal sample Culture for differentiation Rapid tests for capsular polysaccharide T

37、reatment and Prevention Treated with IV penicillin G, cephalosporin Prophylactic treatment of family members, medical personnel, or children in close contact with patient Primary vaccine contains specific purified capsular antigens Neisseria gonorrhoeae (淋病奈瑟菌淋病奈瑟菌) Difference between gonococci and meningococci GonococciMeningococci Exist siteGenital tract, urethra Upper respiratory tract diseaseGenital infectionsMeningitis 咖啡豆形咖啡豆形 Neisseria Gonorrhea, arrowed within a c