Gram Positive Bacteriology

Question 1

what color is gram +

Answer 1

purple/blue

Question 2

what are they 2 gram + branching filaments? how do you differentiate them

Answer 2

actinomyces and nocardia

nocardia is aerobic and acid fast
actinomyces is anaerobic and NOT acid fast

Question 3

catalase + gram + cocci in clusters

Answer 3

staph

Question 4

what are the 2 bacteria that are gram + cocci, catalase + and coagulase -? how do you tell them apart

Answer 4

S. epidermidis
S. saphrophyticus

S. epidermidis is novobiocin sensitive
S. saphrophyticus is novobiocin resistant

Question 5

what gram + cocci are alpha hemolytic

Answer 5

S. pneumoniae and viridans strep

Question 6

what gram + cocci are beta hemolytic

Answer 6

Group A S pyogenes

group B strep agalactiae

Question 7

how do you differentiate the beta hemolytic strep

Answer 7

bacitracin

group A is bacitracin sensitive
group B is bacitracin resistant

Question 8

what are the gamma hemolytic strep

Answer 8

group D enterococcus (E. faecalis)

Group D nonenterococcus (s. bovis)

Question 9

how do you differentiate the gamma hemolytic strep

Answer 9

enterococcus- growth in bile and NaCl

nonenterococcus (only grows in bile not salt)

Question 10

Of the beta hemolytic strep, which is PYR +

Answer 10

step pyogenes (group A) is PYR +
group B is pyr-

Question 11

of the beta hemolytic strep, which is CAMP +

Answer 11

group A is CAMP-

group B is CAMP+

Question 12

what of gram + has “lacent shaped” diplococci

Answer 12

step pneumo

Question 13

how do you differentiate the alpha hemolytic strep

Answer 13

s. pneumo- optochin sensitive

viridans strep- optochin resistant

Question 14

which of the strep is bile soluble? insoluble? what does this mean

Answer 14

s penumoniae is bile soluble (lysed by bile)

viridans strep is bile insoluble (not lysed by bile)