Bacteriological Profile of Nosocomial Pneumonia and Current State of Antibiotic Resistance in the Military Hospital of Avicenne

This retrospective study, conducted over five years, aimed to assess the bacteriological profile of nosocomial pneumonia, the antibiotic resistance of isolated bacteria, and changes in these parameters over time. The analysis reviewed 660 samples from the microbiology department at the Military Hospital of Avicenne in Marrakech, Morocco, covering the period from January 1, 2017, to December 31, 2021. Among these samples, 303 microorganisms were identified from 251 specimens, confirming diagnoses of nosocomial pneumonia. Microorganism identification and antibiograms were performed using the Phoenix100 automated system from Becton Dickinson. The results revealed that 73% of the isolated microorganisms were Gram-negative bacilli, with <i>Acinetobacter baumannii</i> (29.4%) being the most common, followed by Enterobacteriaceae (28%), particularly <i>Klebsiella pneumoniae</i> (15.5%) and <i>Pseudomonas aeruginosa</i> (10.9%). Gram-positive cocci made up 22.5% of isolates, with <i>Staphylococcus aureus</i> (15.2%) being the most prevalent, while yeasts were present in 3.6% of cases. A polymicrobial nature was observed in 19.12% of samples. <i>A. baumannii</i> strains showed high resistance to most antibiotics, with an imipenem resistance rate of 88.5%; colistin was the only effective agent against these strains. In contrast, <i>P. aeruginosa</i> exhibited broad sensitivity to antibiotics, with only an 11.1% resistance rate to ceftazidime and good sensitivity to imipenem (80%). Extended-spectrum beta-lactamase production was noted in 11.5% of Enterobacteriaceae, mainly <i>K. pneumoniae</i>. Methicillin-resistant <i>S. aureus</i> prevalence was low at 11.6%, and all <i>S. aureus</i> strains were vancomycin-sensitive. The study highlights the importance of prudent antibiotic use, enhanced hospital hygiene practices, and ongoing monitoring of bacterial resistance. These measures are vital for developing therapeutic strategies suited to local epidemiology and reducing infections caused by multidrug-resistant microorganisms.