IUBio

Urine culture procedure question

Fergus McClelland redux at nospam.perdrix.demon.co.uk
Sat May 30 18:46:14 EST 1998


I have got the impression that the standard culturing tests for urine
may miss a large percentage of positives. Could anyone please explain
to me the sense of the following case?

A relative of mine, (brother-in-law), suddenly started to suffer with
anterior urethral pain, together with some perineal pain and various
other symptoms in the same area. These were sometimes made worse by
urination, sometimes made better by urination. To save waiting weeks
for an appointment with a urologist, he took a quick trip to the
walk-in Genito-Urinary Medicine clinic in the local hospital.
They did their standard tests for sexually transmitted diseases,
though the doctor said she was sure there was nothing there. "I found
some groups of inflammatory Gram positive bacteria in your urine but
we'll wait and see what the lab says".
The lab tests were all negative. So, what had happened to the
bacteria? I spoke to the lab. They seemed a bit worried and evasive,
suggesting that he could always send in another sample if he wanted.
A year later, he was still in pain, (his own GP having said that she
knew nothing much about prostate infections and had to be guided by
the hospital). He had bought some reagent "dipsticks" and found a low
level of leucocytes were indicated. He phoned the hospital doctor and
told her. He asked her why the bacteria she had found had not cultured
the year before, (she had no idea), and told her of the dipstick
result.

He was given Doxycycline which had no effect. 

A year later his urine, semen and EPS were examined by him at oil
immersion. He found Gram positive cocci.

At 37 degrees they grew like wildfire in his urine. Phone call to
hospital doctor again. More questions about the tests. Doctor sneering
and dismissive, saying if he wanted to see a urologist that was what
he should do.
Speaking to others in that clinic on the phone, it transpired that
they only do a few tests to samples, looking for specific pathogens.
They "did not know" who had looked at his urine previously - before
sending it to the lab; saying it might have been a nurse rather than
the consultant.

Another year later, after a few courses of antibiotics from his GP
which were of no help, he and the doctor decided to send another
sample to the hospital laboratory.

This time, prostate massage was performed before giving a start of
stream sample. Some was taken and kept. The sample was handed in at
the hospital in less than an hour, with a standard card from his
doctor, on which the doctor had written: "Dysuria. ?UTI" and had
"culture and sensitivity" ticked off. A note from the patient was
stapled to the hospital card, explaining that the urine was collected
after prostate massage and would therefore contain WBCs and Gram
positive cocci, as there was a large number of both in his EPS.
ONE DAY later. the hospital wrote to the doctor "11 - 20 WBC per cmm,
0 Red blood cells per cmm. No growth".

The sample kept by the patient at 37 degrees was by that time showing
a great deal of growth of a Gram positive coccus, in diplococci,
chains and bunches.

So, spoke to the hospital, telling them about the past experience as
well. The chief microbiologist was rude and defensive - saying they
had done the tests they always do for "UTI". She had not seen the note
from the patient, as she would only have seen what was typed into the
hospital computer by the department's receptionist. Having looked at
it afterwards she said it made no sense to her. She, another
microbiologist and the head of pathology all said that the patient was
culturing wrongly. By using urine, they said, he was using an
"enriched medium". (Isn't that the point? To get a large amount of
bacteria for sensitivity testing?). Also, they said the GP was wrong,
that if he had written "?prostatitis" they would have looked closer.
AS it was, they took 5 microlitres only and cultured for 24 hours, on
a sensitivity plate, and got no growth. They did not use a microscope
at all, saying that they do not on urine samples for "UTI". They said
that the GUM clinic had probably said "?UTI" also, which would explain
that negative result as well. They said "Send in another sample with
"?prostatitis" and "Urine after EPS" written on the card and we would
look more closely. He has not yet done so, being rather disenchanted.

All comments, private and public - and explanations from
microbiologists - warmly welcomed.

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