Question

A young lady presents with fever, dysuria and pain in the lower abdomen. Uncomplicated acute cystitis was diagnosed. Which among the following is not true?

• A. Nitrate test positive for the urine sample
• B. E. coli colony count < 10^3 bacteria/ml
• C. 1 pus cell per 7 fields in wet film of patient's urine
• D. 1 bacillus per oil-immersion field in Gram-stained urine sample

Hint:

Significant bacteriuria needs high counts, not fewer than 10^3/ml.

Answer 1

The Correct Option is B

Step 1: The patient has acute uncomplicated cystitis, a urinary tract infection most often due to E. coli.
Step 2: The nitrate (nitrite) reduction test is positive when nitrate-reducing organisms such as E. coli are present, so option A is true.
Step 3: Pyuria is expected; significant pyuria corresponds to roughly > 10 pus cells/mm3, which in a wet film equals about 1 or more pus cells per several fields, so option C is consistent with infection and is true.
Step 4: The presence of 1 or more bacteria per oil-immersion field in an uncentrifuged Gram-stained sample correlates with significant bacteriuria (about 10^5 organisms/ml), so option D is true.
Step 5: Significant bacteriuria for symptomatic cystitis is taken as 10^5 organisms/ml by the classic criterion, and even the lower symptomatic cut-off is around 10^2 to 10^3. A colony count of < 10^3 bacteria/ml is regarded as insignificant or contaminant level and does not support the diagnosis of cystitis. Hence this statement is NOT true.
Conclusion: The false statement is option 2, so the correct answer is option 2, matching the printed key.