Moraxella catarrhalis in upper respiratory tract of healthy Yemeni children/adults and paediatric patients: detection and significance.

A highly variable carriage rate of Moraxella catarrhalis has been reported in the literature. In order to assess the reasons for this variability, detection rates of this organism from various sites of the upper respiratory tract of children and adults were studied. Throat swabs, oral swabs and nasal swabs from 131 children, 96 adults and 64 paediatric patients with upper respiratory tract infections were cultured on a selective medium. Detection rates of 31.4% in children less than three years of age, 38.5% in children between 4 and 12 years, 11.7% in adults and 21.9% in patients were found, respectively. The reasons for high variability in the carriage rates were many including the number and site of specimen collection, media used for isolation and identification criteria. All isolates were sensitive to amoxycillin-clavulanic acid and co-trimoxazole. A significantly higher share of M. catarrhalis isolates from patients were beta-lactamase producers (12/14, 85.7%) as compared to normal healthy subjects (41.9%), suggesting a cautious approach in the use of beta-lactam antibiotic in respiratory tract infections.