Bacterial Meningitis Agents Isolated from Cerebrospinal Fluid and Their Antimicrobial Resistance Profiles

Aim: Meningitis is an inflammation of the meninges surrounding the brain and spinal cord. Bacterial meningitis typically presents acutely and is associated with high morbidity and mortality. Therefore, early diagnosis and appropriate treatment are crucial. This study aims to identify the frequency of bacterial meningitis pathogens in our hospital, assess their antimicrobial resistance profiles, and support empirical treatment decisions.Material and Methods: Cerebrospinal fluid (CSF) cultures submitted to our hospital's Medical Microbiology Laboratory between January 2019, and December 2024 were retrospectively analyzed. Bacterial identification and antimicrobial susceptibility testing were performed using automated systems.Results: A total of 4101 CSF samples from 1908 patients were evaluated, with bacterial growth detected in 11.48% of samples. The most common isolates were Staphylococcus epidermidis (29.36%), Acinetobacter baumannii (11.06%), Klebsiella pneumoniae (8.94%), and Staphylococcus aureus (7.66%). Methicillin resistance was found in 38.89% of S. aureus and 82.35% of coagulase-negative staphylococci (CNS). Extended-spectrum β-lactamase was detected in 66.67% of Escherichia coli and 90.48% of K. pneumoniae. Meropenem resistance was observed in 52.38% of K. pneumoniae, 76.92% of A. baumannii, and 20% of Pseudomonas aeruginosa, while E. coli showed no resistance.Conclusion: The most frequent isolate was CNS, followed by A. baumannii, K. pneumoniae, and S. aureus. High carbapenem resistance in A. baumannii and K. pneumoniae presents a challenge for empirical therapy. This underscores the importance of microbiological data in guiding antibiotic selection. Regular monitoring of local pathogens and resistance rates is essential for effective antimicrobial planning.