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

Abstract

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 directly from urine samples to facilitate rapid diagnosis of antibiotic susceptibility. A prospective study was conducted from July 2019 to November 2019. Patients in whom urine culture tests were performed were eligible. Each 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. In total, 350 urine samples were analysed. Urinary tract infection (UTI) was diagnosed in 214 patients. ESBL-producing Enterobacterales were isolated from 79 samples. The 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. The 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 useful point-of-care test to guide appropriate antimicrobial use in patients with UTI.