Impact of the beta-lacta test on the management of urinary tract infections at the emergency department.

INTRODUCTION: Rapid detection of extended-spectrum ß-lactamases is essential. In this study, we evaluated the potential impact of ß-lacta test on both the times to appropriate antibiotic therapy and to the implementation of patient isolation measures. PATIENTS AND METHODS: We included prospectively all the patients admitted to the emergency department for clinical suspicion of urinary tract infection. Compared with physician's decision, we analysed the potential impact of ß-lacta test on the initial antibiotic therapy and on the implementation of hygiene measures. This study has been registered under number NCT02897609. RESULTS: We included 203 patients, 43% with acute pyelonephritis and 21% with acute prostatitis. The ß-lacta test had a 95.2% sensitivity and a 99.5% specificity to detect extended-spectrum ß-lactamases. Taking the ß-lacta test results into account would have decreased significantly both the times to appropriate therapy and to isolation measures from 54 to 2.7 h and from 55.2 to 2.6 h, respectively. CONCLUSION: The ß-lacta test could reduce significantly the times to appropriate therapy and implementation of isolations measures.

Optimization of the ß LACTA test for the detection of extended-spectrum-ß-lactamase-producing bacteria directly in urine samples.

The ß LACTA™ test (BLT) is a chromogenic test detecting resistance to third-generation cephalosporins on bacterial colonies. Some studies have shown that this test can be used directly in urine samples. The aim of this study was to determine the optimal conditions of use of this test in order to detect the ESBL-producing bacteria directly in urine samples. During a 4-months period, a total of 365 consecutive urine samples were tested with the BLT using the recommendation of the manufacturer. We isolated 56 ESBL-producing bacteria and 17 AmpC-overproducing bacteria. ESBL- and/or AmpC ß-lactamase-producing bacteria isolates were systematically characterized by disc diffusion antibiotic susceptibility testing interpreted according to the guidelines of EUCAST. The sensitivity and the specificity for 3GC-resistance detection, regardless the mechanism of resistance, were, respectively, 60.3% and 100%, whereas for ESBL detection, it was, respectively, 75.4% and 99.7%. We applied then modification of the initial protocol considering urines with a bacteriuria >1000/µL, a reading time at 30 min and considering any change of the initial colour as positive. The overall sensitivity was 81% and the sensitivity for ESBL-detection raised to 95.7%.