Investigation of EDTA-carbaNP-direct test for the detection of metallobetalactamases in Pseudomonas aeruginosa

• Published in: Journal of global antimicrobial resistance. 2024-12, Vol.39, p.19-20
• Main Authors: Tutan, Hanife, Mazlumoğlu, Bilge, Çizmeci, Zeynep, Çekin, Zuhal Kalaycı, Cömert, Füsun, Tanriverdi, Elif Seren, Aktaş, Elif
• Format: Article
• Language: English
• Subjects: carbapenem resistance; ceftazidime/avibactam; metallobetalactamases; Pseudomonas aeroginosa
• ISSN: 2213-7165
• DOI: 10.1016/j.jgar.2024.10.060

WHO has included carbapenem-resistant Pseudomonas aeruginosa (CR-PA) in the "critical" priority pathogens list. Ceftazidime-avibactam(CAZ-AVI) is one of the limited treatment options in CR-PA infections. Early detection of metallo-beta-lactameses(MBL) is important because CAZ-AVI is not effective against MBL-producing isolates. To modify the carbaNP-direct test with EDTA and evaluate its use in MBL detection and prediction of CAZ-AVI resistance CR-PA isolates. 403 CR-PA isolates from five centres in Türkiye were included. Susceptibility tests were done using EUCAST criteria. The isolates were tested for blaVIM, blaIMP,blaNDM, blaOXA-48, blaOXA-51, blaOXA-23/58, blaKPC and blaGES using Biospeedy Carbapenem-Resistance qPCR kit and GES Antibiotic-Resistance kit (Bioeksen,Türkiye). We modified carbaNP-direct test described by Pasteran et al. by adding a third tube with EDTA(%5). The isolates with carbapenemase genes were subjected to carbaNP-direct test and EDTA-carbaNP-direct test. EDTA-carbaNP-direct test was considered positive if the tube without EDTA turned yellow while the tube with EDTA remained red(Figure) and negative if both tubes turned yellow. Carbapenemase genes were detected in 75(18.6%) of the isolates. CarbaNP-direct test was positive in 31(41.3%) of the isolates. Of the 31 isolates, 23 were positive for EDTA-carbaNP-direct test. All of these 23 isolates were MBL producers and resistant to CAZ-AVI. CAZ-AVI susceptibility, PCR,carbaNP-direct and EDTA-carbaNP-direct test results are shown in Table. The positivity of carbaNP-direct test in CR-PA is limited, however, EDTA-carbaNP-direct test have detected all MBL-producing isolates when carbaNP-direct test was positive. This test can be used for MBL detection and prediction of CAZ-AVI resistance in carbaNP-direct test positive isolates.