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Tricky Ques

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pr20
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12/17/07 - 08:16 PM

A 27 year old woman,after returning home from her honeymoon,has developed urinary frequency,dysuria,and urgency.Her urine is grossly bloody.Which lab data are most likely to define the causative agent?

A. A gm-ve diplococcus,which is oxidase+ve but does not ferment maltose
B. A gm+ve coccus,which is catalase+ve and coagulase-ve
C. An optochin resistant,catalase-ve,gm+ve coccus
D. A gm+ve bacillus grown on a low oxidation-reduction medium
E. A gm-ve bacterium capable of reducing nitrates to nitrites

hope4dabest
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12/17/07 - 10:58 PM

bactitech
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12/17/07 - 11:06 PM

The most likely organism that they are looking for is E. coli. E is the only gram negative rod. I frankly do not know the nitrate reaction for this organism, as we just don't use it to ID E. coli. So....I don't know whether it is E or not.

The second most likely organism they are looking for is Staph. saprophyticus. The answer to this would be B, as it is a Staph, which are all catalase pos. S. sapro is one of the coagulase negative Staphylococci, so the coag would be negative.

The most common cause of cystitis in women of child-bearing age is E. coli.

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hope4dabest
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12/17/07 - 11:19 PM

bactitech wrote:

The most common cause of cystitis in women of child-bearing age is E. coli.

Kaplan i think says its saprophyticus for women of child bearing age...but i am not sure

hero
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12/17/07 - 11:41 PM

bactitech
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12/18/07 - 11:28 PM

Trust me - we do NOT see that many cultures with S. saprophyticus in the lab. We DO see many cultures positive for E. coli.

Of course, many of these patients are treated empirically without culture, so that has to be taken into consideration.

I have been reading cultures out for nearly 30 years. We get 100-150 cultures/day at our lab. I don't read cultures daily but I read them often. I went in Saturday and read out the late cultures that came in Friday evening. I set up about 10 EC's and reported out one S. sapro from the day before. I did culture review for the entire weekend's cultures last night. I think I saw one other S. sapro besides the one I signed out on Saturday. I saw LOTS and LOTS of EC's.

That's why this is tricky. Do you believe Kaplan for your tests or do you believe what a real micro lab has as its workload??? Do whichever gives you the good test score....

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Aashi
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12/18/07 - 11:55 PM

Honeymoon cystitis----------->MCC is E.coli------------->E

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hope4dabest
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12/19/07 - 12:00 AM

bactitech wrote:
Do you believe Kaplan for your tests or do you believe what a real micro lab has as its workload??? Do whichever gives you the good test score....

Direct attack on the sentiments
I will believe the microbiologist nod

pr20
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12/19/07 - 05:36 PM

Ans is E.
Even though Staph.Saprophyticus can cause honeymoon cystitis, E.coli induced cystitis is highest in sexually active females.It generally reduces nitrates and is also a lactose fermenter.

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