Background: The chromogenic culture medium, MPO, was compared to culture on CLED (cystein, lactose, electrolyte-deficient) agar for the detection, enumeration and identification of urinary tract pathogens.
Methods: A total of 1,080 clinical urine specimens were assessed. All samples were inoculated in MPO and CLED using the calibrated loop method.
Results: Among 145 positive urine samples, 171 strains of bacteria were isolated (111 Escherichia coli, 26 Enterococcus spp., 12 Proteus spp., 10 Enterobacteriaceae from the Klebsiella-Enterobacter-Serratia group, 5 Pseudomonas aeruginosa, 4 Streptococcus agalactiae, 3 Staphylococcus spp. and 4 Candida albicans. For all samples, enumeration of microorganisms was comparable with the two media studied. Identification was also similar, except for 6 cases in which Enterococcus spp. were only detected with the chromogenic medium.
Conclusions: Overall urine culture results with MPO chromogenic medium were similar to those obtained with CLED, making it a feasible alternative to the standard medium. Moreover, use of a chromogenic technique implies a significant reduction in workload, since additional tests to identify the microorganisms isolated are not needed in most cases.