Evaluation of the DipStreak, a New Device with an Original Streaking Mechanism for Detection, Counting, and Presumptive Identification of Urinary Tract Pathogens

Abstract

ABSTRACT DipStreak is a new urine culture device with two types of agar attached back-to-back on a plastic paddle. It combines dip-slide technology and an original streaking inoculation mechanism, allowing for bacterial counting and colony isolation. The performance of the DipStreak device with two different medium formulations, CHROMagar and MacConkey media in study A and UriSelect 3 and MacConkey media in study B, was evaluated and compared to that of the reference streak method by using plates of cystine-lactose-electrolyte-deficient (CLED) agar, tryptic soy agar with 5% sheep blood, and UriSelect 3 medium. In study A, 2,000 urine specimens were processed and 511 cultures were found positive. The DipStreak device and the UriSelect 3 and CLED medium plates gave the same detection rate, 99.7%. For the direct identification of Escherichia coli , Proteus mirabilis , and Enterococcus sp. isolates, the DipStreak device and the UriSelect 3 medium plate showed overall sensitivities of 97 and 93.4%, respectively. In study B, 3,000 urine specimens were processed and 714 cultures were found positive. The DipStreak device and the UriSelect 3 and CLED medium plates gave detection rates of 99.4, 99.9, and 99.2%, respectively. For the direct identification of E. coli , P. mirabilis , and Enterococcus sp. isolates, the DipStreak device and the UriSelect 3 medium plate showed overall sensitivities of 88 and 94.4%, respectively. In conclusion, the DipStreak device with both medium formulations represents an attractive and excellent screening method for the reliable detection, counting, and presumptive identification of urinary tract pathogens. It enables bedside urine inoculation and provides a valid means of transporting the sample back to the laboratory, decreasing drastically the rate of false-positive results due to bacterial overgrowth and reducing associated costs.