Microbiology Flashcards
Gram+ organisms stain…
Purple
Stain well due to thick peptidoglycan layer
Gram- organisms stain…
Pink
Thinner peptidoglycan layer doesn’t retain stain well
Endotoxin is produced by…
Gram- organisms
Part of the cell wall
Exotoxin is produced by…
Gram+ organisms
Exported from the cell
Gram+ cocci in chains are?
Streptococci
Gram+ cocci in clusters are?
Staphylococci
The test to classify different Streptococci spp.?
Haemolysis
Alpha (partial) - Strep. pneumoniae + viridans
Beta (complete) - Group A (pyogenes) and B Strep.
Gamma (none) - Enterococcus sp.
Examples of: Alpha-haemolytic Streptococci?
(Is this partial/full/no haemolysis)
Strep. pneumoniae + “viridans” group
Examples of: Beta-haemolytic Streptococci?
(Is this partial/full/no haemolysis)
Group A Strep. (Strep. pyogenes), Group B Strep.
Examples of: Non-haemolytic Streptococci?
(Is this partial/full/no haemolysis)
Enterococcus sp.
The test to distinguish Staphylococcus aureus from other Staph. spp.?
Coagulase test
+ve = Staph. aureus
-ve = other Staph. spp. (common skin commensals)
Treatment of choice for Staph. aureus infection?
Flucloxacillin
Examples of gram- cocci in pairs (diplococci)
Neisseria meningitidis and Neisseria gonorrhoeae
Some examples of Gram- bacilli
Bordetella H. influenzae Coliforms Pseudomonas Campylobacter
Examples of coliforms that are gut commensals
E. coli
Klebsiella sp.
Proteus sp.