STREPTOCOCCUS & ENTEROCOCCUS

Cocos Gram-Positivos Streptococcus

Gênero Streptococcus Fisiologia e Metabolismo Anaeróbios facultativos Exigentes nutricionalmente (fatores de crescimento) Capnofilia Catalase Negativa (2H2O2 ---> O2 + 2H2O) Beta, Alfa, ou Gama Hemolíticos em ágar sangue

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

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

Streptococcus pyogenes (Contraste de fase)

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

Erisipelas NOTE: eritema bolhas

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

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, WBC’s, PMN's, platelets, etc.) Causes sub-surface hemolysis on BAP Stimulate release of lysosomal enzymes SLO titer indicates recent infection (300-500 in pediatric populations)

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

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

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.

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

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

Streptococcus agalactiae Group B Streptococcus Streptococcus agalactiae

Streptococcus agalactiae

Group B Streptococcal Infections

Grp B Streptococcal Infections (cont.)

Age-Specific Attack Rates of Group B Streptococcal Disease

Epidemiology of Neonatal Group B Streptococcal Disease

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

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

Hippurase NEG

Grp B Streptococci and Campylobacter Hippurase POS

Streptococcus pneumoniae Também chamado de pneumococcus

Streptococcus pneumoniae Infections

Pneumococcal Infections (cont.) Epidemiology (cont.)

S. pneumoniae Diplococcus

S. pneumoniae: lancet-shaped diplococcus

S. pneumoniae Virulence Factors

S. pneumoniae Seasonal Incidence

Comparison of Morbidity & Mortality for Bacterial Meningitis

Genetic Variation (Mutation)

Beginning of Molecular Genetics

Transformation (In vivo) (Griffith)

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

Streptococcus pneumoniae Optochin Sensitivity Taxo P Streptococcus pneumoniae

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

Enterococcal Infections

Enterococcal Infections (cont.)

Important nosocomial pathogen Vancomycin resistant Enterococcus (VRE)

Enterococcus Diagnostic Laboratory Tests Resistant to bile Esculin hydrolysis BEA media

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

Esculin Bile Assay