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