Moraxella catarrhalis: An emerging pathogen in bronchopulmonary infections

Abstract

Background: Moraxella catarrhalis (M. catarrhalis) is a common pathogen in the human upper respiratory tract. This microbe is also implicated in chronic lower respiratory tract infections as well as conjunctivitis, sinusitis, meningitis, otitis media, osteomyelitis, endocarditis, etc. Objectives: This study was carried out to know various facets of M. catarrhalis infection among adults with bronchopulmonary infections and the related antibiotic susceptibility pattern. Materials and Methods: A hospital-based study was carried out among adult participants with history of respiratory tract infection admitted to a tertiary care teaching hospital in Karnataka during the period of May 2007 to April 2010. A total of 912 early morning sputum samples were collected, processed with standard procedures, and analyzed. Results: Out of all the sputum samples, M. catarrhalis was the third most important pathogen (16.01%). Most of these M. catarrhalis isolates were sourced from participants with bronchopneumonia (31.51%), followed by chronic bronchitis (25.34%), bronchiectasis (25.34%), and bronchial asthma (17.81%). M. catarrhalis infection was predominantly noted among males (78.08%) and in older age group (22.60%), i.e., 61-70 years. All strains of M. catarrhalis were sensitive to tetracycline, co-trimoxazole, chloramphenicol, and gentamicin; 75.34% were resistant to penicillin, ampicillin, and amoxycillin. Surprisingly, all strains were resistant to erythromycin; 37 (25.34%) were beta-lactamase positive. Conclusions: M. catarrhalis is one of the emerging pathogens in bronchopulmonary infections, and the beta-lactamase-producing strains imply its ability for antibiotic resistance.