Impact of beta-lactamase detection reagent on rapid diagnosis of ESBL-producing pathogens using urine samples of patients with Gram-negative bacteriuria.

INTRODUCTION The rapid increase of extended-spectrum beta-lactamase (ESBL)-producing pathogens makes it difficult to choose appropriate antimicrobials in patients with Gram-negative bacterial infection. The Cica-beta reagent (KANTO CHEMICAL, Tokyo, Japan) is a chromogenic test that detects ESBLs from bacterial colonies. This study aimed to reveal whether Cica-beta reagent could detect ESBLs from urine samples to facilitate rapid diagnosis of antibiotic susceptibility. METHODS We conducted a prospective study from July 2019 to November 2019. Patients in whom urine culture tests were performed were eligible. The urine sample was centrifuged, and the pellet was mixed with Cica-beta reagent. The test was considered positive when the enzymatic reaction turned from yellow to red or orange. RESULTS We analysed 350 urine samples. Urinary tract infection (UTI) was diagnosed in 214 of the patients. ESBL-producing Enterobacterales was isolated from 79 samples. Cica-beta test showed sensitivity of 79.8% and specificity of 99.3% in patients with Gram-negative bacteriuria. Sensitivity and specificity improved to 90.2% and 100%, respectively, in patients with UTI. CONCLUSION Cica-beta test could be an efficient test for the detection of ESBL-producing pathogens in urine. By providing immediate information about ESBLs, it might be a point-of-care test to guide appropriate antimicrobial use in patients with UTI.