Bacteriological profile of nosocomial infections caused by multidrug-resistant bacteria in intensive care units

Background: Multidrug resistant bacteria are the most important threats to public health. Typically associated with nosocomial infections. However, some Multidrug resistant bacteria have become prevalent causes of community-acquired infections.

Objective: The objective of this study is to examine the bacteriological profile of nosocomial infections caused by multidrug-resistant bacteria in intensive care patients.

Methods: This is a descriptive study conducted in the microbiology department of the Ibn Tofail Hospital of the Mohamed VI University Hospital in Marrakech over a 12-month period from January to December 2024, including all samples received by the microbiology laboratory from patients hospitalized in the intensive care unit of the Ibn Tofail Hospital. Microorganism identification and antibiograms were performed using standard bacteriological tests, supplemented by biochemical identification panels (BioMérieux, France). Antimicrobial resistance profiles were determined using the agar diffusion method, in accordance with EUCAST standards.

Results: During this period, 160 samples were received. Bacterial cultures were positive in 88 samples (55%), including 32 (36%) multi- or extensively drug-resistant bacteria (MDR/XDR). The average age of these patients was 33 years, with a predominance of males (sex ratio = 8.3). Nosocomial pneumonia was the predominant infection (38%), followed by bacteremia (28%). Gram-negative bacteria accounted for 94% of MDR bacterial isolates. Imipenem-resistant Acinetobacter baumanii (IRAB) was found in 19 samples (59%), followed by carbapenemase-producing Enterobacteriaceae (CPE) (25%), extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL) (9%), and methicillin-resistant Staphylococcus aureus (MRSA) (6%). In terms of antibiotic susceptibility, IRAB strains were resistant to all antibiotics of medical interest, with the exception of colistin (100% susceptibility). MRSA strains were 50% resistant to trimethoprim-sulfamethoxazole, with 100% sensitivity to aminoglycosides, fluoroquinolones, and fosfomycin. E-ESBLs were represented by Klebsiella pneumoniae, Enterobacter cloacae, and Escherichia coli, with resistance to aminoglycosides (100%), trimethoprim-sulfamethoxazole (100%), and fluoroquinolones (33%), as well as preserved susceptibility to colistin and tigecycline (100%). Carbapenemase-producing Enterobacteriaceae were represented by Klebsiella pneumoniae (38%), Enterobacter cloacae (38%), and Escherichia coli (25%). Metallo-beta-lactamases (Ambler class B) were identified in 50% of CPE.

Conclusion: Nosocomial infections caused by multidrug-resistant or extensively drug-resistant bacteria in intensive care units increase morbidity and mortality and require special attention. Prevention is based on rigorous hygiene, appropriate use of antibiotics, and appropriate isolation measures. A strict, multidisciplinary approach is essential to limit their spread.