BIOL 1122 Lecture Notes - Lecture 4: Streptococcus Agalactiae, Lancefield Grouping, Viridans Streptococci
3 May 2017
School
Department
Course
Professor
Document Summary
Common residents of skin and mucous membranes - frequently isolated from clinical samples such as pus, sputum, urine and blood. Differentiated from micrococcus species based on resistance to bacitracin and. Micrococcus not often associated with human infection. Many staph are resistant to penicillin and ampicillin. Catalase positive which differentiates them from streptococci and enterococci. Responsible for nearly 80% of suppurative diseases of the skin: boils. May cause systemic infections (pneumonia and infections of nerve tissues and bone) Dnase +staphylococci: show opaque, clear region around culture. Dnase - staphylococci: are around growth remains green. Clot formation indicaates production of coagulase - Coagulase + dnase + staph - indicative of s. aureus. Required enriched media under reduced oxygen tension (microaerophilic and facultatively anaerobic) Sheep blood agar - environment for differentiation based on hemolytic properties. 3 types of hemolysis produced on bap due to production or lack of hemolysins (streptolysins) Alpha ( )- partial hemolysis - greening - viridans group.
