Moraxella catarrhalis: An often overlooked pathogen of the respiratory tract

Background: Moraxella catarrhalis is an upper respiratory tract commensal which can also be pathogenic. It is now considered as the third most common pathogen of the respiratory tract. Aim: The aim of the present study was to assess and evaluate the risk factors in adults with lower respiratory tract infections which were caused by M. catarrhalis. Material and methods: Sputum samples from 1402 adults with lower respiratory tract infections were studied over two years. M. catarrhalis was isolated from 137 samples. Data such as date, name, sex, age, smoking history and underlying disease conditions were collected to study the risk factors. Results: Most patients (68%) were of above 50 years of age. Underlying risk factors such as COPD (37%) and diabetes mellitus (18%) were seen in a majority of the cases (87%). No underlying risk factors were detected in 12(12.7%) patients. The isolation was more during the colder months (63.5%). While all isolates were susceptible to Amoxyclav, only 14% were sensitive to Penicillin. Conclusion: The isolation of M.catarrhalis should be considered significant in adult patients with lower respiratory tract infections and associated underlying risk factors. Since 86% of the isolates showed penicillin resistance, treatment with appropriate antibiotics should be instituted.