the microbiologic diagnosis of urinary tract
infection, by definition, there must be
>100,000 organisms/cc. This definition is used
because of the common contamination of a
"clean-catch" urine specimen,
especially in females.
- The photograph above shows the
plate from just such a specimen.
- It is growing colonies of at least 3
different types (arrows-
Gram negative rods (GNR), diptheroids (Dips), and
staph coagulase negative (SCN).
- This culture would be signed out
as 'mixed flora, probable contamination'.
- Certain patients may have asymptomatic
bacteruria, with less than 100,000 organisms/cc.
- Pregnant women
are an example of such a patient
population. Any number of organisms may
- In such a case,
it may be worth considering straight
catheterization, to obtain an optimal
- However, you must
consider the risk that you may introduce
organisms by doing a
1999 KUMC Pathology and the University of Kansas,
used with permission; courtesy of Dr. James
Fishback, Department of Pathology, University of
Kansas Medical Center.