Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 18 3 2026 06 07 332 337 Wissal Nordine Department of Biology, Mohamed VI University Hospital Center, Marrakech, Morocco Ayoub Ame Department of Biology, Mohamed VI University Hospital Center, Marrakech, Morocco Taoufik Benhoumich Department of Microbiology, Faculty of Medicine, Cadi Ayyad University, Marrakech, Morocco Asmaa Lamrani Hanchi Department of Microbiology, Faculty of Medicine, Cadi Ayyad University, Marrakech, Morocco Nabila Soraa Laboratory of Microbiology, University Hospital Mohamed VI, Faculty of Medicine and Pharmacy, Cadi Ayyad University, Marrakech, Morocco 2025 11 24 2026 05 06 Background and Objectives: Carbapenemase-producing Enterobacterales (CPE) constitute a critical public health concern due to multidrug resistance and limited available treatment options. This study aimed to assess the in vitro susceptibility of CPE isolates to colistin, fosfomycin, and mecillinam. Materials and Methods: Prospective study was conducted in 2023 at Mohammed VI University Hospital, Marrakech. A total sample of 180 non-duplicate CPE isolates were collected and identified by standard microbiological methods. Antimicrobial susceptibility testing was performed following recommended guidelines. Results: Among the isolates, Klebsiella pneumoniae (60%) and Escherichia coli (14%) predominated. The most common carbapenemase was NDM (62%), followed by OXA-48 (26%) and co-producers (11%). Most isolates were obtained from intensive care (32%), plastic surgery (13%), and neonatology (12%) units. Skin and soft tissue (43%) and bloodstream (21%) were the predominant infected sites. Resistance rates were 25% for colistin, 48% for fosfomycin, and 64% for mecillinam, with frequent co-resistance to fluoroquinolones, aminoglycosides, and cotrimoxazole. Conclusion: The high prevalence of NDM-producing Klebsiella pneumoniae and significant resistance to last-line agents suggest the urgent need for antimicrobial stewardship, optimized therapeutic strategies, and strengthened regional surveillance. https://ijm.tums.ac.ir/index.php/ijm/article/view/5960 https://ijm.tums.ac.ir/index.php/ijm/article/download/5960/1892