Gram Positive Bacteria Flashcards
How do you initially distinguish between Gram positive bacteria (i.e. what feature)
Bacilli (rod-shaped)
Cocci (round/spherical)
how are bacilli distinguished?
Aerobic/anaerobic
what category can aerobic bacilli be broken up into
spore forming and non-spore forming
give an example of a Gram positive, aerobic, non-spore forming bacteria
Listeria monocytogenes
Corynebacterium diptheriae
Give an example of a Gram positive, aerobic spore forming bacterium
Bacillus species
anaerobic bacilli form spores, give an example of a bacterium of this type
Clostridium species:
- Clostridium Difficile (C.Diff)
- Clostridium Tetani
- Clostridium Perfringens
what groups can Gram positive cocci be split into?
Staphylococci (clusters)
Streptococci (chains)
What test is used to distinguish between staphylococci
coagulase test (positive or negative)
What Gram positive staphylococci test positive in the coagulase test
Staph. aureus
what Gram positive staphylococci test negative in the coagulase test
- Staph. epidermidis
- Staph. saprophyticus
What test is used to distinguish between Gram positive Streptococci and what are the results of the test?
haemolysis test:
- partial (alpha) turns blood agar green
- complete (beta) turns blood agar clear
- non-haemolytic has no effect on blood agar colour
what Streptococci organisms produce partial haemolysis?
- Strep. pneumoniae
- viridans streptococci
what streptococci organisms produce complete haemolysis?
- Group A - Strep. pyogenes
- Group B
- Group C
what streptococci organisms are non-haemolytic?
-enterococci, eg:
enterococcus faecalis
What condition(s) are caused by Staph. aureus
Methicillin resistant staph. aureus (MRSA)
Methicillin sensitive staph. aureus (MSSA)
what treatment is used against MRSA
Linezolid and in serious conditions Daptomycin
what condition(s) does Strep. pneumoniae cause?
pneumonia, meningitis, septicaemia
what condition does viridian’s streptococci cause
infective endocarditis (infection of heart valves)
what conditions does (group A) strep. pyogenes cause?
- sore throats
- cellulitis
- necrotising fascitis
what conditions can (group B) strep. agalactiae cause?
- meningitis
- bacteraemia
what do (group D) enterococci cause?
UTIs
what does C. difficile cause?
diarrhoea
can cause pseudomembranous colitis
what does C. perfringens cause?
food poisoning in contaminated food
can cause “gas gangrene” in serious wounds
what does C. tetani cause
tetanus (uncontrolled muscle spasm)
