Staphylococcus vs Streptococcus- 20 Major Differences

Staphylococcus and Streptococcus Differences

Staphylococcus and Streptococcus are Gram-positive and the two most common pathogenic cocci of medical importance. They are both non-motile, non-sporing, and facultative anaerobes which can be differentiated on the following grounds: S.N. Character Staphylococcus Streptococcus 1.       Cellular Arrangement Spherical cells in clusters (grape like clusters). Spherical or ovoid cells in chains or pairs. 2.       Fission/Division Irregular division in all three planes. Division in one linear direction. 3.       Catalase Test Positive (Presence of catalase enzyme) Negative 4.       Halotolerance Halotolerant. … Read more

Streptococcus Selective Agar- Composition, Principle, Preparation, Results, Uses

Streptococcus Selective Agar

Roantree et al introduced a medium for isolation of group A beta-hemolytic streptococci. The medium-enriched with yeast nucleic acid and maltose promoted increased colony size and enhanced clarity and sharpness of hemolytic zones produced by these organisms. Streptococcus Selective Agar is a selective medium recommended for use in the primary isolation of groups A Streptococcus species (S. pyogenes) from oral culture and respiratory specimens. It is designed to inhibit gram-negative bacilli and staphylococci, thereby allowing for the isolation, subculture, and identification … Read more

Streptococcus pyogenes- Group A Streptococcus (GAS)- An Overview

Streptococcus pyogenes- Group A Streptococcus (GAS)

They are also known as Group A Streptococcus (GAS) or Group A (beta-hemolytic) Streptococcus (GABHS). Habitat of Streptococcus pyogenes They are found in the throat and skin of humans. They are commensals of the upper respiratory tract. The 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 time. Morphology of Streptococcus pyogenes Gram +ve bacteria Spherical or oval cocci in chains. 5 to … Read more

Biochemical Test of Streptococcus mutans

Biochemical Test of Streptococcus mutans

Biochemical Test of Streptococcus mutans Basic Characteristics Properties (Streptococcus mutans) Capsule Capsulated Catalase Negative (-ve) Gram Staining Positive (+ve) Hemolysis Alfa Hemolysis Motility Non-motile OF (Oxidative-Fermentative) Facultative anaerobes Oxidase Negative (-ve) Shape Cocci Spore Non-sporing Urease Negative (-ve) VP (Voges Proskauer) Positive (+ve) Fermentation of Adonitol Negative (-ve) Arabinose Negative (-ve) Arbutin Positive (+ve) Cellobiose Positive (+ve) Dulcitol Negative (-ve) Erythritol Negative (-ve) Galactose Positive (+ve) Glucose Positive (+ve) Glycerol Negative (-ve) Glycogen Negative (-ve) Hippurate Negative (-ve) Inositol Negative … Read more

Biochemical Test of Streptococcus agalactiae

Biochemical Test of Streptococcus agalactiae

Biochemical Test of Streptococcus agalactiae Basic Characteristics Properties (Streptococcus agalactiae) CAMP Positive (+ve) Capsule Positive (+ve) Catalase Negative (-ve) Coagulase Negative (-ve) Flagella Non-flagellated Gram Staining Positive (+ve) Hemolysis Beta Hemolysis Motility Non-motile OF (Oxidative-Fermentative) Facultative anaerobes Oxidase Negative (-ve) PYR Negative (-ve) Shape Cocci Spore Non-sporing Urease Negative (-ve) VP (Voges Proskauer) Variable Fermentation of Adonitol Negative (-ve) Arabinose Negative (-ve) Arabitol Negative (-ve) Arbutin Negative (-ve) Cellobiose Variable Dulcitol Negative (-ve) Erythritol Negative (-ve) Fructose Positive (+ve) Galactose … Read more

Hemolysis of Streptococci- Types and Examples with Images

Hemolysis of Streptococci- Types and Examples with Images

Introduction A genus Streptococcus is a heterogeneous group of Gram-positive bacteria. Various streptococci are considered as the normal microbial flora of animals and humans, while some species under favorable conditions can also cause diseases ranging from sub-acute infection to acute or even chronic diseases/infections. Streptococci are spherical organisms that grow in chains because of incomplete separation after the division of the cells. In the earlier days, hemolysis which is lysis of erythrocytes on the blood agar medium by enzymes (toxin) … Read more

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 stain of an aspirated fluid smear from middle ear is useful to demonstrate the bacteria. Culture Sputum or blood is … Read more

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 to epithelial cells 3. Pneumolysin It is intracellular membrane-damaging toxin produced by autolysis. Pneumolysin binds to cholesterol and therefore interacts … Read more

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 gram +ve character in older cultures and appear gram –ve. They are non-sporing and non-motile bacteria. May have pili for … Read more

Biochemical Test of Streptococcus pyogenes

Biochemical Test of Streptococcus pyogenes

Biochemical Test of Streptococcus pyogenes Characteristics Properties (Streptococcus pyogenes) CAMP Negative (-ve) Capsule Capsulated Catalase Negative (-ve) Gram Staining Positive (+ve) Hemolysis Beta Motility Non-Motile OF (Oxidative-Fermentative) Fac. Anaerobes PYR Positive (+ve) Shape Cocci Spore Non-Sporing Urease Negative (-ve) VP (Voges Proskauer) Negative (-ve) 6.5% NaCl Growth Negative (-ve) Fermentation of Adonitol Negative (-ve) Arabinose Negative (-ve) Arabitol Negative (-ve) Cellobiose Variable Dulcitol Negative (-ve) Erythritol Negative (-ve) Fructose Positive (+ve) Galactose Positive (+ve) Glucose Positive (+ve) Glycerol Variable Glycogen … Read more