Staphylococci and Streptococci 0.0 / 5 ? BiologyImmunology and InfectionUniversityNone Created by: georgia160502Created on: 10-01-23 11:32 What is beta haemolysis? Complete haemolysis Characterised by a transparent zone surrounding the colonies 1 of 15 What is alpha haemolysis? Partial haemolysis Colonies typically are surrounded by a green, opaque zone 2 of 15 What is gamma haemolysis? No haemolysis No notable zones around the colonies 3 of 15 How does S. aureus appear on blood agar? Appear as translucent colonies that often have a gold pigment 4 of 15 How does S. epidermis appear on blood agar? Appear as greyish-white colonies 5 of 15 How do staphylococci appear on the Gram stain? Gram-positive cocci Single and grape-like clusters Facultative anaerobic Non-motile Salt tolerant 6 of 15 How do streptococci appear on the Gram stain? Gram-positive cocci Pairs or chains Facultative anaerobic Non-motile 7 of 15 How does the catalase test relate to staph and strep? It can be used to distinguish between staphylococcus and streptococcus. Staphylococcus are positive Streptococcus are negative 8 of 15 Can staph or strep clot plasma by the action of the enzyme coagulase (coagulase test)? Staphlococcus have the ability to clot 9 of 15 What does the deoxyribonuclease test determine? The ability of an organism to produce deoxyribonuclease, an enzyme capable of degrading DNA Staphylococcus aureus can hydrolyse DNA 10 of 15 What is sensitive in the optochin sensitivity test? Streptococcus pneumonide is usually sensitive to optochin other alpha haemolytic streptococcus are usually resistant 11 of 15 What is sensitive in the bacitracin susceptibility test? Streptococcus pyogenesW 12 of 15 What are the characteristics of staphylococci? More than 40 species All parts of normal skin and mucous membrane microbiota Either coagulase positive or negative 13 of 15 What is the most important coagulase-positive species? Staphlococcus aureus- moist skin folds 14 of 15 What is the most important coagulase-negative species? Staphlococcus epidermis- implicated in disease Ubiquitous on the skin, biofilm formation and bloodstream infections 15 of 15
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