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STREPTOCOCCUS&ENTEROCOCCUS. Cocos Gram-Positivos Streptococcus.

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Apresentação em tema: "STREPTOCOCCUS&ENTEROCOCCUS. Cocos Gram-Positivos Streptococcus."— Transcrição da apresentação:


2 Cocos Gram-Positivos Streptococcus

3 Gênero Streptococcus Fisiologia e Metabolismo Anaeróbios facultativos Exigentes nutricionalmente (fatores de crescimento) Capnofilia Catalase Negativa (2H 2 O 2 ---> O 2 + 2H 2 O) Beta, Alfa, ou Gama Hemolíticos em ágar sangue




7 Gênero Streptococcus Sistemas de classificação Quanto à hemólise Quanto ao determinante antigênico Quanto à apresentação clínica Quanto às provas bioquímicas Rebecca Lancefield Classificação de Streptococcus beta-hemolíticos pelo Carbohidrato da parede celular grupo-específico Sorogrupos A a H e K a V Grupos A, B, C, D, e G mais importantes

8 Classificação de Lancefield - Streptococcus Beta-Hemolíticos Grupo A Streptococci: Streptococcus pyogenes Um dos patógenos mais importantes Doenças Supurativas: Faringite; Escarlatina; Infecções cutâneas & de tecidos moles; doenças sistêmicas Não-Supurativas :FRA,GNDA Grupo B Streptococci: Streptococcus agalactiae Doenças sistêmicas, cutâneas, ITU Doenças Neonatais Complicações obstétricas REVIEW

9 Streptococcus pyogenes (Contraste de fase)


11 Streptococcus Pyogenes – Grupo A Faringite eritemato-pultácea Erisipela Impetigo Escarlatina Síndrome do choque tóxico Fascite necrosante, mionecrose, septicemia Doenças não supurativas

12 Erisipelas NOTE: eritema bolhas

13 Determinantes de Patogenicidade Fatores de Virulência Celulares Cápsula Antiphagocytic; Nonspecific adherence Hyaluronic acid (polysaccharide) mimics animal tissue Ácido Lipoteicoico Cytotoxic for wide variety of cells Adherence: Complexes with M protein (LTA-M) and binds to fibronectin on epithelial cells Proteína M LTA-M protein is adhesin Antiphagocytic Inhibits alternate C pathway and opsonization Proteínas M-like: bind IgM and IgG Proteína F: mediates adherence

14 Fatores de Virulência Extracelulares Exotoxinas: Estreptolisina O (SLO): Hemolytic and Cytolytic Prototype of oxygen-labile and thiol-activated cytolytic exotoxins (e.g., Streptococcus, Bacillus, Clostridium, Listeria) Lytic for variety of cells: bind to cholesterol- containing membranes and form arc- or ring- shaped oligomers that make cell leaky (RBC's, WBCs, PMN's, platelets, etc.) Causes sub-surface hemolysis on BAP Stimulate release of lysosomal enzymes SLO titer indicates recent infection ( in pediatric populations)

15 Fatores de Virulência Extracelulares Exotoxinas: Estreptolisina S (SLS): Hemolytic and Cytolytic Oxygen stable, non-antigenic Lytic for red and white blood cells and wall-less forms (protoplast, L- forms) Causes surface hemolysis on BAP Lisogenia: Lysogenized bacteriophages play key role in directing synthesis of various Group A streptococcal enzymes and toxins Pyrogenic Exotoxin (erythrogenic toxin) Phage-associated muralysins (lyse cell walls) produced by both Groups A and C

16 Fatores de Virulência Extracelulares Exotoxinas: Exotoxinas Pirogênicas (Eritrogênicas) (A, B &C) Produced by more than 90% of Grp A strep Lysogeny: Structural gene is carried by temperate bacteriophage, as is the case with diphtheria toxin Mediate pyrogenicity (fever) Causes scarlet fever (scarletiniform) rash Increase susceptibility to endotoxic shock Type C toxin increases permeability of blood-brain barrier Enhance DTH Mitogenic for T lymphocytes (cause cell division), myocardial and hepatic necrosis, decrease in antibody synthesis Immunomodulators (superantigens): stimulate T cells to release cytokines Toxina Cardiohepática

17 Fatores de Virulência Extracelulares Enzimas : Nucleases: Four antigenic types (A,B,C,D) Facilitate liquefication of pus generating growth substrates Nucleases A, C have DNase activity Nucleases B, D also have RNase activity Estreptoquinases : Two different forms Lyse blood clots: catalyze conversion of plasminogen to plasmin, leading to digestion of fibrin C5a Peptidase: destroys C chemotactic signals (C5a) Hialuronidase: hydrolyzes hyaluronic acid Others: Proteinase, NADase, ATPase, phosphatase, etc.

18 Nonsuppurative Sequelae of Acute Group A Streptococcal Infection Acute Rheumatic Fever (ARF) Inflammatory reaction characterized by arthritis, carditis, chorea (disorder of CNS with involuntary spastic movements), erythema marginatum (skin redness with defined margin), or subcutaneous nodules Within 2-3 weeks following pharyngitis Epidemic pharyngitis: ARF in as many as 3% Sporadic pharyngitis: ARF in 1 per 1000 Morbidity & mortality linked to subsequent disease of heart valve (Rheumatic Heart Disease) Poorly understood pathogenesis with several proposed theories including cross-reactivity of heart tissues & strep AGNs ?? (Type ?? hypersensitivity, exotoxins, direct invasion) II REVIEW

19 Nonsuppurative Sequelae of Acute Group A Streptococcal Infection (cont.) Acute Glomerulonephritis Follows either respiratory (pharyngitis) or cutaneous (pyoderma) streptococcal infection Associated with well-defined group of M-types Incidence varies from <1% to 10-15% Most often seen in children manifesting as dark, smoky urine with RBC's, RBC casts, white blood cells, depressed serum complement, decreased glomerular filtration rate Latent period: 1-2 weeks after skin infection and 2-3 weeks after pharyngitis Granular accumulations of immunoglobulin due to deposition of immune complexes within the kidney (Type ?? Hypersensitivity) III REVIEW

20 Group B Streptococcus Streptococcus agalactiae


22 Group B Streptococcal Infections

23 Grp B Streptococcal Infections (cont.)

24 Age-Specific Attack Rates of Group B Streptococcal Disease

25 Epidemiology of Neonatal Group B Streptococcal Disease

26 Group B Streptococcus S. agalactiae Diagnostic Laboratory Tests CAMP factor positive Hippurase positive

27 CAMP Factor Test S. aureus (Spingomyelinase C) Group B Streptococcus (CAMP Factor) Group A Streptococcus Enhanced Zone of Hemolysis

28 Hippurase NEG

29 Hippurase POS Grp B Streptococci and Campylobacter


31 Streptococcus pneumoniae Também chamado de pneumococcus

32 Streptococcus pneumoniae Infections

33 Epidemiology (cont.) Pneumococcal Infections (cont.)

34 S. pneumoniae Diplococcus

35 S. pneumoniae: lancet-shaped diplococcus

36 S. pneumoniae Virulence Factors

37 S. pneumoniae Seasonal Incidence

38 Comparison of Morbidity & Mortality for Bacterial Meningitis

39 Genetic Variation (Mutation)

40 Beginning of Molecular Genetics

41 Transformation (In vivo) (Griffith)

42 Streptococcus pneumoniae Diagnostic Laboratory Tests Optochin sensitivity (Taxo P disc)

43 Optochin Sensitivity Taxo P Streptococcus pneumoniae


45 Enterococcus faecalis Enterococcus faecium GI tract of humans and animals Group D carbohydrate cell wall antigen Formerly Streptococcus

46 Enterococcal Infections

47 Enterococcal Infections (cont.)

48 Important nosocomial pathogen Vancomycin resistant Enterococcus (VRE)

49 Enterococcus Diagnostic Laboratory Tests Resistant to bile Esculin hydrolysis BEA media

50 Bile Esculin Agar POS Enterococcus Group D Streptococcus Bile Esculin Agar NEG

51 Esculin Bile Assay

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