Biochemical Test of Streptococcus pneumoniae

Biochemical Test of Streptococcus pneumoniae

Biochemical Test of Streptococcus pneumoniae Basic Characteristics Properties (Streptococcus pneumoniae) Bile Solubility Positive (+ve) Catalase Negative (-ve) Gram Staining Positive (+ve) Hemolysis Alfa Hemolysis Motility Non-motile OF (Oxidative-Fermentative) Facultative anaerobes Oxidase Negative (-ve) Shape Diplococci Spore Non-sporing Urease Negative (-ve) VP (Voges Proskauer) Negative (-ve) Fermentation of Arabinose Positive (+ve) Arbutin Negative (-ve) Dulcitol Negative (-ve) Erythritol Positive (+ve) Fructose …

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Laboratory diagnosis, Treatment and Prevention of Streptococcus pneumoniae

Laboratory diagnosis, Treatment and Prevention of Streptococcus pneumoniae

Laboratory diagnosis of Streptococcus pneumoniae Specimen: Sputum, blood, endotracheal aspirate, bronchoalveolar lavage, cerebrospinal fluid (CSF), pleural fluid, joint fluid, abscess fluid, bones, and other biopsy material. Microscopy Gram staining of sputum shows lancet shaped Gram-positive cocci in pairs. Fresh emulsified sputum mixed with antiserum causes capsule swelling (the quellung reaction) for identification of pneumococci. In acute pneumococcal otitis media, Gram …

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Virulence factors, Pathogenesis and Clinical manifestations of Streptococcus pneumoniae

Virulence factors, Pathogenesis and Clinical manifestations of Streptococcus pneumoniae

Virulence factors of Streptococcus pneumoniae Polysaccharide capsule The capsule is antiphagocytic, inhibiting complement deposition and phagocytosis. 2. Cell wall associated polymers and proteins Teichoic acid – binds to epithelial cells and activates alternative complement pathway Protein adhesion – binds to epithelial cells Peptidogylcan – activates alternative complement pathway Phosphorylcholine – mediates invasion of host cell F protein – mediates attachment …

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Laboratory diagnosis of Streptococcus pyogenes

Laboratory diagnosis of Streptococcus pyogenes

1. Specimens Throat swab Pus Cerebrospinal fluid Blood Serum for antibody determinant 2. Smear Gram staining Purple color cocci in chain arrangement Not to be confused with Viridans Streptococci from throat swab sample since both have same appreance 3. Culture Culture on blood agar Addition of bacitracin in inoculum: S pyogenes are sensitive to bacitracin Colonial appearance: Grayish white, transparent …

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Habitat and Morphology of Streptococcus pyogenes

Habitat and Morphology of Streptococcus pyogenes

Habitat of Streptococcus pyogenes They are found in throat and skin of human. They are commensals of upper respiratory tract. Carrier rate of S. pyogenes in the respiratory tract is only few in adults, over 10% in children attending kindergarten. Opportunistic pathogens May survive in dust for some times. Morphology of Streptococcus pyogenes Gram +ve bacteria Spherical or oval cocci in …

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Bile Esculin Test- Principle, Procedure and Result Interpretation

Bile Esculin Test- Principle, Procedure and Result Interpretation

Bile Esculin Test- Principle, Procedure and Result Interpretation Objectives of Bile Esculin Test This test is used for the presumptive identification of enterococci and organisms in the Streptococcus bovis group. The test differentiates enterococci and group D streptococci from non–group D viridans streptococci. Principle of Bile Esculin Test Gram-positive bacteria other than some streptococci and enterococci are inhibited by the bile salts …

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