chromogenic media for urine cultures can be cost-effective

Abstract

Background: Chromogenic media for diagnostic urinary bacteriology have several advantages over traditional media, such as cysteine-lactose-electrolyte deficient (CLED) medium. Chromogenic media allow for easier recognition of mixed growth, save time, reduce workload and provide higher detection rates. However, the cost of chromogenic media is significantly higher compared to CLED and performance of chromogenic media varies depending on the manufacturer. In the present study, performance, turn-around time and cost of Uriselect4 chromogenic medium was compared to CLED.

Methods: For performance analysis, 351 midstream urine (MSU) samples from September 2005 to December 2005 were directly plated in parallel on Uriselect4 and CLED agar using the calibrated loop technique. Isolates on Uriselect4 were presumptively identified according to the product insert. For cost-effectiveness analysis, we included 1,972 consecutive MSU samples from May 2005 to July 2006. We compared the cost of required materials as well as technologists’ or specialists’ time for each medium examined.

Results: No significant differences were found between the isolation rates of urinary pathogens on the studied media. The procedure using chromogenic media for uropathogens is slightly cheaper than the procedure using CLED, considering the proportion of bacteriuria positive samples (50.5 %) and the distribution of taxa among isolates (namely Escherichia coli with 59.6 %) observed in our laboratory. At the current isolation proportion in MSU samples processed in our laboratory, the average time to reporting results could be decreased by 0.3 days.

Conclusions: Use of chromogenic media for urine investigations offers multiple advantages without increasing costs compared to procedures using CLED.