Multicentre clinical trial to evaluate microbial spectrum in acute diffuse otitis externa in the residents of Ukraine

Abstract

Introduction: Acute diffuse otitis externa is a spread skin inflammation of the external ear canal of the bacterial origin. It is reported at an incidence of up to 10% among healthy population of all age groups. Treatment is known to be based on the empirical approach for prescribing topical antibacterials. Therefore studying the bacterial spectrum of otitis externa causative agents is of great value in terms of relevant antimicrobial therapy. Aim: The objective of the study was to evaluate microbial spectrum in diffuse otitis externa in patients – residents of Ukraine. Materials and methods: Four hundred and ninety-three out-patients diagnosed with acute diffuse otitis externa were enrolled. Microbial composition of the external ear canal microflora was tested and aetiologically relevant titres of colony-forming units (CFU) were determined. Criteria for evaluation: titres of 104 to 106 CFU and >106 CFU were considered aetiologically relevant. titres of <104 CFU were considered aetiologically nonrelevant. Results and discussion: In the majority of cases of acute diffuse otitis externa, infection with Staphylococcus aureus in aetiologically relevant titres is reported in 53.2% and Pseudomonas aeruginosa in 23.6%. Cases of multimicrobial infection predominantly involving Gram-negative flora were also reported in 27.9%; each of them results in no more than 2 to 3% of otitis externa. Titres of Candida spp. (3.2%) and Staphylococcus epidermidis (2.6%) were measured as aetiologically non-relevant. Conclusion: common microbial pathogens in acute diffuse otitis externa in patients of the Ukrainian population are Staphylococcus aureus and Pseudomonas aeruginosa. Multimicrobial associations predominantly involving Gram-negative flora, which do not exceed 2 to 3% of cases. Fungal infections are a rare cause of otitis externa.