Clinical evaluation of a novel chromogenic agar dipslide for diagnosis of urinary tract infections

The performance of a novel dipslide (DipStreak; Novamed, Israel) consisting of chromogenic agar (Uriselect 3; Sanofi Pasteur, France) and blood agar media was evaluated prospectively and compared to that of conventional urine culture for the diagnosis of urinary tract infection. A total of 1070 clean-catch urine specimens obtained from 251 hospitalized patients and 819 outpatients were processed. The overall performance of the DipStreak was as follows: sensitivity, 95.7%; specificity, 99.2%; agreement, 89.8%; accuracy, 98%; positive predictive value, 98.5%; and negative predictive value, 97.7%. A total of 270 urine specimens were positive by both DipStreak and conventional culture. The chromogenic agar allowed rapid identification of organisms in 211 (78.1%) cultures, while isolates in the other 59 (21.9%) cultures remained unidentified. The results indicate that the DipStreak device coupled with the Uriselect 3 agar represents a convenient and accurate method for inoculation of urine specimens, quantitation of bacteria, diagnosis of significant bacteriuria, and presumptive identification of isolates.