M154-1

Urine (indwelling catheter): 50-100x 10^6 cfu/L Escherichia coli  and >100x 10^6 cfu/L Morganella morganii – Shipped 15 February 2016 

HISTORY

MAIN EDUCATIONAL POINTS from M154-1

1. Generally, two gram negative isolates at high colony in a urinary infection should be fully worked up. Three or more are most often an indication of contamination and may be rejected or prompt a request for recollection if clinical symptoms persist.
2. Intrinsic resistance in some species of gram-negative bacilli should not be overlooked. The isolate may test as susceptible but treatment will likely be ineffective.
3. Patients in long term care facilities often have vague symptoms of urinary tract infections. In most cases no more than two isolates at high concentrations should be considered as significant.

Full critique (PDF)