Evaluation of the DIRAMIC system for detection of urinary tract infections and for Escherichia coli identification.

Abstract

The use of the DIRAMIC system for the detection of urinary tract infections (UTI) and the possibility to identify Escherichia coli in the same culture media was evaluated. The results from DIRAMIC detection system were compared to counts of colony forming units per milliliter (CFU/ml) of urine inoculated in CLED Medium; 884 urine specimens were processed taking > or =10(4) CFU/ml as criteria of positive urine culture counts. For E. coli identification, substrates for the determination of beta-glucuronidase and tryptophanase were incorporated to the culture medium and named DETID-Ec. Outputs were compared to those from API RAPIDEC-ur strips. The DIRAMIC system can detect UTI, with a sensitivity and specificity of 82.25 and 94.49%, respectively. It was possible to identify E. coli during detection with 87.50% of sensitivity and 95.96% of specificity. The small volumes of culture medium used in the DIRAMIC system as well as the short times for the detection make the system a rapid and economical method for screening UTI. Furthermore, by using DETID-Ec culture medium the time and the number of biochemical tests necessary for the E. coli identification are lowered.