W04_05 Intro to bacteriology I Flashcards
what gives gram-positive organisms the ability to retain the colour?
1: thicker peptidoglycan layer; 2: magnesium ribonucleate has affinity for crystal violet-iodine complex 3: less lipid in cell walls, so less permeability to decolorizer
the presence of what in a sputum sample is cause for rejection of the sample?
squamous epithelial cells. indicates too much oral contamination
classify staphylococcus spp
GP, cocci, O2+
classify streptococcus spp
GP, cocci, O2+
classify enterococcus spp
GP, cocci, O2+
classify corynebacterium spp
GP, bacilli, O2+
classify bacillus spp
GP, bacilli, O2+
classify clostridium spp
GP, bacilli, AnO2
classify neisseria spp
GN, cocci, O2+
classify haemophilus spp (coccobacilli)
GN, cocci/bacilli, O2+
classify e. coli
GN, bacilli, O2+
classify bacteroides spp
GN, bacilli, AnO2
what is this
staphylococcus spp.
name important staphylococcus species
s.aureus
coag-neg staphylococci:
(s. epidermidis, s. lugdunensis, s. saprophyticus)
what’s the coagulase test?
sees if the bacteria will cause serum to coagulate
what is this
streptococcus spp.
(enterococcus also looks like this)
name important streptococci
beta-hemolytic streptococci:
(s. pyogenes (group A strep.), s. agalactiae (group B strep))
alpha-hemolytic streptococci:
(s. pneumoniae, viridans group strep)
what’s the difference between beta and alpha hemolysis?
beta is clearer on the blood agar. alpha is greener.
what’s this?
viridans group strep. note the long chains.
what’s this?
group A strep. note the short chains.
what’s this
streptococcus pneumoniae. (gram positive diplococci)
what’s this?
enterococcus spp. (gram positive cocci in short chains).
e. faecium and e. faecalis are common species
what’s this?
corynebacterium spp.
note the v-shapes and the palisades (lines)
jeikeium, urealyticum and diphtheriae are important.
what’s this
bacillus. gram-positive bacilli, typical skin flora
important bacillus: b. anthracis (not common)
what’s this?
escherichia coli. gram-negative bacilli. bipolar staining.
important enteric GN: e.coli, salmonella spp., enterobacter spp, etc. etc. refer to 46/61 of slides)
what’s this?
haemophilus spp. GN coccobacilli.
important: H. influenzae.
what’s this?
neisseria spp. GN diplococci.
important: N. meningitidis, N. gonorrhoeae
what’s this?
clostridium spp. GP bacilli. AnO2
important: C. tetani, C. botulinum, C. perfringens, C. difficile
what’s this?
bacteroides spp. GN bacilli. AnO2. note they’re scraggly because they’re exposed to air.
