EVALUATION OF DIRECT DISC DIFFUSION SUSCEPTIBILITY TESTING FOR BACTERIURIA USING DILUTED URINE AGAINST STANDARD CDS METHOD

Consecutive urine specimens with greater than or equal to 10(9) organi sms/L on microscopy were diluted 1:100 and direct disc diffusion susce ptibility tests performed. Subsequently, the standard Calibrated Dicho tomous Sensitivity (CDS) test was performed on all isolates. Urines wi th >2 isolates or where growth was <10(8) colony forming units (CFU)IL were excluded. Only Gram negative organisms were considered. 361 urin es were evaluated, 324 with one and 37 with 2 isolates, comprising 255 Escherichia coli, 49 klebsiella, 41 proteus, 29 either citrobacter, e nterobacter, providencia, serratia or alcaligenes, and 14 Pseudomonas aeruginosa. There were 2272 organism/antimicrobial test comparisons. A concordance of 98.5% was obtained. The results are considered accepta ble for routine clinical use.