Bile Solubility Test- Principle, Procedure, Types, Results, Uses

Bile Solubility Test- Principle, Procedure and Result Interpretation

What is Bile Solubility Test? Bile solubility test is a biochemical test used for the differentiation and confirmation of Streptococcus pneumoniae from other alpha-hemolytic Streptococci. The bile solubility test has been used as an essential test for the differentiation of S. pneumoniae as it allows the distinction between the two species S. pneumoniae and Streptococcus pseudopneumoniae, which is a challenging task. The …

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Biochemical Test of Bacteria

Biochemical Test of Bacteria

Biochemical Test of Bacteria Biochemical reactions are very important in the identification of bacterial isolates and in the identification of different bacterial species. These tests depend on the presence of certain enzymes, such as catalase, oxidase, urease, gelatinase, etc., produced by the bacteria. Different bacteria produce varying spectra of enzymes. For example, some enzymes are necessary for the bacterium’s individual …

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12 Differences between Pneumococcus and Viridans streptococci

Differences between Pneumococcus and Viridans streptococci

Streptococcus pneumoniae can be differentiated from Viridans streptococci by various features: S.N. Properties Pneumococcus Viridans streptococci 1 Morphology Lanceolate or flame-shaped Round/oval 2 Arrangement Gram-positive cocci in pairs Gram-positive cocci in long chains 3 Capsule Present Absent 4 On blood agar Draughtsman or carom coin colony Convex shaped colony 5 Liquid medium Uniform turbidity Granular turbidity 6 Bile solubility Soluble …

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Aerobic and Facultatively Anaerobic Gram-Positive Cocci

Aerobic and Facultatively Anaerobic Gram-Positive Cocci

Enterococcus faecalis and Enterococcus faecium Clinical Features Urinary tract infections, peritonitis, bacteremia, endocarditis Virulence Factors Relatively avirulent Staphylococcus aureus Clinical Features Suppurative infections: impetigo, folliculitis, furuncles, carbuncles, wounds Disseminated infections: bacteremia, endocarditis, pneumonia, empyema, osteomyelitis, septic arthritis Toxin-mediated infections: toxic shock syndrome, scalded skin syndrome, food poisoning Virulence Factors Possess thick peptidoglycan layer, capsule, protein A, various toxins (cytotoxins, exfoliative …

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Habitat and Morphology of Streptococcus pneumoniae

Habitat and Morphology of Streptococcus pneumoniae

Habitat of Streptococcus pneumoniae Streptococcus pneumoniae are found worldwide. Found in primates, livestock and felines. They are the part of normal flora of upper respiratory tract infection in humans. Mostly found in throat and nasal passage. They infection mostly children in winter seasons. They are Mesophilic, 30 to 35°C. Morphology of Streptococcus pneumoniae They are gram positive bacteria. May lose …

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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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