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?
Strep. pneumoniae + “viridans” group
Examples of: Beta-haemolytic Streptococci?
Group A Strep. (Strep. pyogenes), Group B Strep.
Examples of: Non-haemolytic Streptococci?
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.
Examples of coliforms that are gut pathogens
Salmonella sp.
Shigella sp.
E. coli 0157
The name of the toxin produced by E. coli 0157 is…
Verotoxin (VTEC)
Treatment of choice for coliform infections?
Gentamicin