Objective: Cefiderocol is a siderophore cephalosporin used as a last resort treatment for infections caused by carbapenem-resistant Enterobacterales (CRE), which pose a threat to public health. This study aimed to determine cefiderocol susceptibility among CRE isolates from the Western Marmara Region of Türkiye and to evaluate the association between cefiderocol susceptibility and carbapenemase type. Materials and Methods: Susceptibility testing of CRE isolates collected from hospitals in Çanakkale and Edirne provinces was performed using the disk diffusion method according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) guidelines. Minimum inhibitory concentration (MIC) testing was performed for isolates resistant to cefiderocol or categorized within the area of technical uncertainty (ATU). The presence of Klebsiella pneumoniae carbapenemase (KPC), oxacillinase-48 (OXA-48), metallo-β-lactamase (MBL), and AmpC β-lactamase (AmpC) was investigated using the combination disk method. Results: A total of 120 CRE isolates were included in the study; 100 of which were collected from Çanakkale and 20 from Edirne. According to EUCAST, cefiderocol susceptibility was 92.5% (n=111), whereas it reached 99% (n=119) under CLSI. The prevalence of KPC, OXA-48, and MBL among the isolates was 48.9%, 31.6%, and 16.3%, respectively. Cefiderocol susceptibility rates among isolates producing KPC, OXA-48, and MBL were 90%, 100%, and 75%, respectively. Conclusion: Isolates producing OXA-48 were more susceptible to cefiderocol than MBL-producing isolates. Cefiderocol may represent an important therapeutic alternative for the treatment of infections caused by CRE in Türkiye. Keywords: Cefiderocol, antimicrobial resistance, Enterobacterales
Bayrak et al. (Fri,) studied this question.