Bacterial Etiology and Antimicrobial Resistance in Ear Infections: A Cross-Sectional Study from Tripoli, Libya

Abstract

This cross-sectional study included 100 patients aged 18 to 60 from a teaching hospital in Tripoli, Libya, with an ear infection. Following normal bacteriological procedures, sterile ear swabs were used to collect middle ear secretions from study participants for culture and antimicrobial susceptibility testing. A total of eight bacterial species and one fungal species were recovered. The microbiological analysis of the clinical isolates demonstrated a predominance of Gram-negative bacteria (48.0%), followed by Gram-positive bacteria (34.0%) and fungal isolates (14.0%), while 4.0% of samples showed no microbial growth. Among Gram-negative organisms, Pseudomonas aeruginosa was the most frequently recovered pathogen, accounting for 28.0% of all isolates. Gram-positive bacteria were primarily represented by Staphylococcus epidermidis (16.0%) and Staphylococcus aureus (11.0%). Candida albicans was the only fungal pathogen identified in this cohort. Cefotaxime showed 100% resistance in Pseudomonas and Klebsiella spp., while gentamicin (100% efficacy in Gram-positive cocci; 85.7% in Pseudomonas) and amikacin (100% in Klebsiella; 92.9% in Pseudomonas) were the most effective agents, underscoring the urgent need for targeted antibiotic selection. Gram-negative bacteria, Gram-positive bacteria, and fungi in samples were the leading cause of ear infections, and they were generally susceptible to most of the antibiotics tested. Amikacin, cefepime, gentamicin, ciprofloxacin, and meropenem could be valuable in the empirical management of ear infections