DipStreak -
Streaking Dipslide
for Diagnosis of Urinary Tract
Infection
DipStreak
is a convenient device for transporting
urine samples as well as for isolating, enumerating and
identifying specific bacteria in urine. A unique streaking
mechanism permits the isolation of single colonies even when
the original bacterial population of the sample was as high
as 100,000,000 organisms per milliliter. DipStreak
is intended for use in both physicians' office laboratories
and clinical laboratories.
SUMMARY
AND EXPLANATION
DipStreak
comprises a plastic
paddle with two types of agar attached back-to-back, housed
in a closed transparent plastic tube. A ring with elongated
prongs is attached to the end of the paddle so that there
are prongs on each side of the slide. The ends of the
prongs are dipped into the urine sample. Upon re-insertion
into the plastic tube, the prongs are prevented from moving
and the agar surfaces are inoculated with bacteria as the
paddle passes over the prongs. The result is a series of
streaks of decreasing bacterial concentration that permits
isolation of single colonies even when the original
bacterial population of the sample was as high as
100,000,000 organisms per milliliter.
|
DipStreak offers the combined advantages of the
urine dipslide and the classical plate isolation
methods.
|
REAGENTS
Six different agar combinations are available:
|
BD-510 |
CLED/MacConkey |
BD-910 |
CLED/UriSelect* |
|
BD-610 |
TSA-Blood/MacConkey |
BD-911 |
TSA-Blood/UriSelect* |
|
BD-710 |
Columbia CNA/MacConkey |
BD-912 |
MacConkey/UriSelect* |
Other agar
combinations can be manufactured upon request.
*Chromostreak
UriSelect is a non-selective agar medium composed of a rich
nutrient base containing three peptones, which sustains
growth of all urinary tract pathogens; chromogenic
substrates for detection of the bacterial enzymes
beta-glucuronidase and beta-glucosidase; and tryptophan for
detection of tryptophanase activity (indole production) and
of tryptophan deaminase activity (TDA).
 |
Interpretation of Results
In
the past, the presence of > 100.000 CFU/ml was
regarded as a positive result while <10.000 CFU/ml
was negative. From 10.000 to 100.000 CFU/ml were
considered borderline cases, which called for repeat
examination. Today, the trend is for specific
medical departments such as Urology, Nephrology and
Pediatrics to report down to 1000 CFU/ml. A colony
density chart is supplied for reporting results. If
bacterial growth yields three or more different
kinds of colonies, this is most likely due to
contamination. The test should be repeated.
Preliminary identification of the bacteria can be
made based on type and color of colonies. |
Colony Density Chart
Colonies
|
<10 |
10-24 |
25-50 |
|
>50 |
|
|
CFU/ML |
103 |
104 |
105 |
106 |
107 |
108 |
Dipstreak
