Introduction: Moraxella catarrhalis is a gram negative, aerobic, oxidase positive diplococcus. It is frequently found as a commensal of the upper respiratory tract. In recent years Moraxella has gained importance as a pathogenic organism causing upper respiratory tract infections in apparently healthy children and in elderly population. The present prospective study was carried out in the microbiology department of our diagnostic centre with the aim of studying the prevalence of Moraxella catarrhalis in respiratory specimens and to study the antibiogram. Materials and Methods: This was a prospective study carried out in Microbiology department of our diagnostic centre between July to December 2018. A total of 886 patients of both sexes registered for culture and sensitivity testing were included in the study. Samples were collected by following thorough aseptic techniques in sterile containers/swabs and were plated on 5% sheep blood agar and Maconkey agar and incubated at 37°C for 18-24 hours. Isolated organism was identified by Gram’s stain and colony morphology and further by biochemical tests. Antibiotic sensitivity was done on Vitec II (Biomerieux) Results: Moraxella catarrhalis was isolated in 16 out of 886 total specimens received for culture with an incidence of 1.81%. Moraxella catarrhalis was isolated in 7 sputum samples and in 9 (56.25%) throat swab specimens. Out of 108 sputum samples, no growth was observed in 66 (61.11%) patients and Moraxella was isolated in 7 (6.48%) cases. Out of 126 throat swab specimens, no growth was observed in 51.59% patients and Moraxella was isolated in 9 (7.14%)patients Conclusion: Clinical interest in M. catarrhalis has gained momentum in recent years only, so the epidemiological data are lacking regarding the prevalence of M. catarrhalis infection. More studies with larger sample size are required to correctly assess the pathogenecity and resistance pattern of M. catarrhalis.

Keywords: Moraxella; Beta lactamase; Commensals; Upper respiratory tract.