urine culture

Dilworth bactitech at hortonsbay.com
Fri Feb 9 22:11:03 EST 2001

Yes,  that is the basic methodology behind urine cultures.  However, with
specialized patients, i.e. urology or kidney patients with longstanding infections
and/or treatments, the docs sometimes treat with counts of <10,000/ml.

If the gentlemen is getting into a situation where he might have a chronic
prostatitis, low numbers could be significant, depending on the opinion of the
urologist.  I have personally seen orders from urologists that say "work up all
organisms regardless of count."

Also, about ten years ago, I attended a workshop on urinary tract infections -
guidelines for reporting, given by the Cleveland Clinic.  At that time (I don't know
whether this is still done at this institution), they plated most urines with a .001
microliter loop (each colony equalling 1,000 organisms/ml).  However, with women of
childbearing age (15-45 years) they also plated with a .01 microliter loop (each
colony equalling 100 organisms/ml), as these women were at risk for UTI's with low
counts.  My laboratory plates catheterized urines with a .01 and clean catch urines
with .001.

This is why I think it important that the original poster check with a urologist and
talk to him about low numbers in a urine culture if he has a relapse.  Urologists
should know what guidelines their lab uses for urine culture reporting.

Judy Dilworth, M.T. (ASCP)

pmonk at attglobal.net wrote:

> Urine is considered a sterile fluid. 0.01ml of urine is plated onto a BAP or MAC
> agar plate.  Take the number of colonies that grow and multiply by 100.  Some
> labs use complex protocols for working up urine cultures.  A good guide line is
> one organism that is greater then 100000, work it up.  If a urine has more then
> one organisim with each colony or 100000 then do not report and ask for a new
> specimen.  If less then 10000 then it is probable contamination from when it was
> collected and will not be worked up.

More information about the Microbio mailing list

Send comments to us at biosci-help [At] net.bio.net