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 … Read moreAerobic and Facultatively Anaerobic Gram-Positive Cocci

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 … Read moreHabitat and Morphology of Streptococcus pneumoniae

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 … Read moreBiochemical Test of Streptococcus pneumoniae

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 … Read moreLaboratory diagnosis, Treatment and Prevention of Streptococcus pneumoniae

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 … Read moreVirulence factors, Pathogenesis and Clinical manifestations of Streptococcus pneumoniae

Bile Solubility Test- Principle, Procedure and Result Interpretation

Bile Solubility Test- Principle, Procedure and Result Interpretation

Bile Solubility Test- Principle, Procedure and Result Interpretation Objective of Bile Solubility Test This test differentiates Streptococcus pneumoniae (positive–soluble) from alpha-hemolytic streptococci (negative–insoluble). Principle of Bile Solubility Test Bile or a solution of a bile salt (e.g., sodium desoxycholate) rapidly lyses pneumococcal colonies. Lysis depends on the presence of an intracellular autolytic enzyme, amidase. Bile salts lower … Read moreBile Solubility Test- Principle, Procedure and Result Interpretation