Microbiological Profile and Antimicrobial Resistance in Intensive Care Unit Patients With Sepsis and Septic Shock: A Prospective Single-Center Study From a Tertiary Care Intensive Care Unit

Background Sepsis and septic shock remain the major causes of mortality in intensive care units (ICUs), increasingly complicated by antimicrobial resistance. However, microbiological profiles and resistance patterns vary widely across regions, and data from North African ICUs remain limited. This study aimed to describe the distribution of pathogens according to infection site, to analyze antimicrobial susceptibility patterns, and to assess the burden of multidrug-resistant organisms among ICU patients with sepsis and septic shock. Methods We conducted a prospective observational study in a mixed medical-surgical ICU at Ibn Rochd University Hospital, Casablanca, Morocco, over a 30-month period (January 2023-June 2025). Adult patients with sepsis or septic shock, defined according to Sepsis-3 criteria, were included. Microbiological analysis was restricted to patients with at least one clinically significant isolate, and only the first isolate per infectious episode was considered. Data included infection sites, pathogen distribution, antimicrobial resistance profiles, and ICU mortality. Results Eighty patients were included, yielding 192 microbiological samples, of which 126 (65.6%) were positive, corresponding to 142 clinically significant isolates. Polymicrobial infections were identified in 22/80 patients (27.5%). Gram-negative bacteria predominated overall, with Acinetobacter spp. (28/142, 19.7%), Escherichia coli (26/142, 18.3%), and Pseudomonas aeruginosa (20/142, 14.1%) as the most frequently identified pathogens. Multidrug resistance (MDR) was observed in 58/142 isolates (40.8%) and in 36/80 patients (45%). The highest MDR rates were found in Acinetobacter spp. (22/28, 78.6%), which was also the leading pathogen in bloodstream (18/52, 34.6%) and respiratory (12/42, 28.6%) infections. Acinetobacter spp. exhibited high resistance rates to ciprofloxacin (20/26, 76.9%), gentamicin (20/23, 87.0%), and imipenem (21/27, 77.8%), while colistin resistance remained low (3/28, 10.7%). The overall ICU mortality rate was 36/80 (45%). MDR infections were significantly associated with higher ICU mortality (24/36 (67%) vs. 12/44 (27%), p < 0.001). Conclusion In this North African ICU, sepsis was characterized by a high burden of multidrug-resistant Gram-negative bacteria, with a prominent role of Acinetobacter spp. across major infection sites. MDR infections were associated with higher ICU mortality, highlighting the potential clinical impact of antimicrobial resistance in critically ill patients. These findings suggest that empirical antibiotic strategies should be adapted to local ICU ecology, with consideration of multidrug-resistant Gram-negative bacteria in high-risk patients and a site-specific approach.