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NBME 18 Answers

nbme18/Block 2/Question#34

25 yo woman, fatigue for 3 weeks

Greening reaction on blood agar

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 +1  upvote downvote
submitted by namira(13),

Mitral valve and teeth cleaning are key words for Strep viridans diagnosis. It is alpha hemolytic so it would have a greening reaction.

important mention to watch out for:

The optochin answer is incorrect because it says "inhibition BY optochin". Viridans is resistant to optochin so that answer is incorrect.





 +0  upvote downvote
submitted by namira(13),

Mitral valve and teeth cleaning are key words for Strep viridans diagnosis. It is alpha hemolytic so it would have a greening reaction.

important mention to watch out for:

The optochin answer is incorrect because it says "inhibition BY optochin". Viridans is resistant to optochin so that answer is incorrect.





 -1  upvote downvote
submitted by famylife(37),

This is strep pneumo, which has alpha hemolysis (green)

breis  How is this differentiated from Strep Virdans which is Optochin Resistant? Because Strep Pneumo would also be inhibited by optochin* +  
mjmejora  its strep viridans. Strep viridans has a "protected chin mask" and strep pneumo is "exposed" in the sketchy. +