Akademik Veri Yönetim Sistemi
Diagnostic Microbiology and Infectious Disease, cilt.113, sa.4, 2025 (SCI-Expanded)
Background: WHO has included carbapenem-resistant Pseudomonas aeruginosa (CR-Pa) in the high priority pathogens list. Ceftazidime-avibactam (CZA) is one of the limited treatment options in CR-Pa infections. Early detection of metallo-β-lactamases (MBL) is important because CZA is not effective against MBL-producing isolates. Aim: To modify the CarbaNP-direct test (CNPdt) with EDTA and evaluate its use in MBL detection and prediction of CZA resistance CR-Pa isolates. Methods: 398 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, blaKPC and blaGES genes using Biospeedy Carbapenem-Resistance qPCR kit and GES Antibiotic-Resistance kit (Bioeksen, Türkiye). We modified CNPdt described by Pasteran et al. by adding a third tube with ethylenediaminetetraacetic acid (EDTA). The isolates with carbapenemase genes were subjected to CNPdt and EDTA-CNPdt. EDTA-CNPdt was considered positive if the tube without EDTA turned yellow while the tube with EDTA remained red and negative if both tubes turned yellow (Fig. 1). Results: Carbapenemase genes were detected in 55 (13.8 %) of the isolates. CNPdt was positive in 31 of the isolates. Of the 31 isolates, 23 were positive for EDTA-CNPdt. All of these 23 isolates were MBL producers and resistant to CZA. PCR, CNPdt, EDTA-CNPdt and CZA susceptibility test results are shown in Table 2. Conclusion: The positivity of CNPdt in CR-Pa is limited, but EDTA-CNPdt detected 100 % of MBL-producing isolates when CNPdt was positive. This test can be used for MBL detection and prediction of CZA resistance in CNPdt positive isolates.