Microbiology: Streptococci Flashcards
describe the appearance of streptococci
gram positive cocci in chains
describe the growth of strep bacteria
aerobic and facultative anaerobic
what are streptococci bacteria classified by
alpha haemolysis(partial haemolysis) beta haemolysis(complete haemolysis) gamma haemolysis(no haemolysis)
beta-haemolytic streptococci are pathogenic organisms, give an example of harmful toxin they produce
haemolysin, damages tissues
how are beta-haemolytic streptococci further classified
by antigenic structure on surface(serological grouping)
Group A, Group B, Group C
give examples of infections caused by Group A and by Group B strep
Group A = throat, severe skin infections
Group B = meningitis in neonates
what are the 2 important categories of alpha-haemolytic streptococci
strep. pneumoniae and strep. viridans group
where is strep. pneumoniae most commonly seen
pathogen that is most common cause of pneumonia
where is strep. viridans most commonly seen
commensals of throat, mouth, vagina
can cause infection in endocarditis
what is included in non-haemolytic streptococci
enterococcus species(eg E. faecalis, E. faecium)
where are non-haemolytic streptococci seen
commensals of bowel
common cause of urinary tract infection
what type of beta-haemolytic strep are strep pyogenes
group A strep
what different infections can be caused by strep pyogenes
infected eczema, impetigo, cellulitis, erysipelas, necrotising fasciitis
what treatment is used for strep pyogenes infection
penicillin(will also be treated with flucloxacillin)
what treatment is used for necrotising fasciitis
life-threatening, so immediate surgical debridement as well as antibiotics depending on causative organism
