Akademik Veri Yönetim Sistemi
Infectious Diseases and Clinical Microbiology, cilt.8, sa.2, ss.179-189, 2026 (ESCI, Scopus, TRDizin)
Objective: The global spread of antibiotic resistance, particularly in carbapenem-resistant Gram-negative bacteria, has become a major public health concern. Recently developed antibiotics—ceftazidime-avibactam (CAZ-AVI), ceftolozane-tazobactam (TOL-TAZ), meropenem-vaborbactam (MER-VAB), eravacycline (ERV), and delafloxacin (DLX)—represent promising therapeutic alternatives. This study aimed to assess resistance patterns to these novel agents among Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa isolates from intensive care units (ICUs). Materials and Methods: Between January 2023 and December 2024, isolates obtained from ICU cultures at Uşak Training and Research Hospital were analyzed. Species identification was performed using the VITEK® 2 and VITEK® MS systems (bioMérieux, Marcy-l'Étoile, France). Antimicrobial susceptibility testing was conducted with the VITEK® 2 AST XN21 card (bioMérieux, Marcy-l'Étoile, France), while colistin (COL) susceptibility was determined by broth microdilution. Results were interpreted according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines, and statistical analysis was performed using Pearson’s chi-square test (p<0.05). Results: A total of 1525 clinical samples yielded 850 K. pneumoniae, 219 P. aeruginosa, and 456 A. baumannii isolates. Klebsiella pneumoniae isolates demonstrated high resistance rates to TOL-TAZ and MER-VAB, while resistance to CAZ-AVI was observed in approximately half of the isolates. Among P. aeruginosa strains, resistance rates were comparatively lower, particularly for CAZ-AVI and TOL-TAZ. Acinetobacter baumannii exhibited nearly complete resistance to meropenem and notable resistance to COL, with elevated minimum inhibitory concentration (MIC) values for MER-VAB and DLX. Temporal analysis revealed rising CAZ-AVI resistance (p=0.024) but declining TOL-TAZ resistance (p=0.004) in K. pneumoniae; significant decreases in TOL-TAZ (p<0.001) and COL resistance (p=0.002) in P. aeruginosa; and a marked reduction in COL resistance among A. baumannii (p<0.001). Conclusion: Although novel β-lactam/β-lactamase inhibitor combinations expand therapeutic options against multidrug-resistant Gram-negative infections, high resistance rates— particularly among K. pneumoniae isolates—remain concerning. This large-scale study from Türkiye, which provides MIC-based data on five novel agents, highlights the importance of continuous surveillance and rational antibiotic use to preserve their efficacy.