Microbial etiology of acute otitis externa - a one year study

摘要

Acute otitis externa is a diffuse inflammation of the external ear canal, caused by bacterial and/or fungal infections that may cause persistent, severe pain, swelling of the skin and detritus accumulation in the auditory canal accompanied by mild hearing loss. Microbiological samples were collected from the external ear canal of 59 outpatients and analyzed for the presence of aerobic pathogens responsible for otitis externa and the isolated strains sensitivity to currently tested antibiotics. Staphylococcus aureus was the most common microorganism encountered in the external ear canal (31 of 59 cases), followed by Pseudomonas aeruginosa (12 of 59 cases), Escherichia coli (4 cases) and Proteus vulgaris (3 cases). The unexpected high incidence of Staphylococcus aureus (58% of all cases), compared to data found in the literature that report a much smaller percent, was accompanied by a high level of resistance of the isolated Staphylococcus aureus strains to usual antibiotics such as ciprofloxacin (32%), cefuroxim (36%), azithromycin (40%), gentamicin (26%) and chloramphenicol (27%). Although otitis externa is considered a trivial pathology and many times receives empiric treatment, the results of our survey highlight the need for determination of the specific microbial etiology and of antibiotic susceptibility spectrum to enable a targeted treatment.