A colorimetric amplification-based method for identification of Moraxella catarrhalis, a human respiratory tract pathogen

Moraxella catarrhalis is a significant pathogen associated with both upper and lower respiratory tract infections. This study aims to identify M. catarrhalis using the ompCD gene, which encodes a major outer membrane protein. Spectrophotometry was used to evaluate the accuracy of the colorimetric method by measuring the A450/A570. The colorimetric measurements and PCR method specificity were assessed utilizing twenty bacterial samples. The results of M. catarrhalis detection confirmed the presence of a specific band at 273 base pairs and a light red color, with an A450/A570 ratio of 1.5. However, 100% specificity was observed in negative samples with an A450/A570 ratio of 1.15 or less, lacking an amplicon band and showing a deep red color. Furthermore, the selectivity of the techniques was confirmed. The methods revealed a detection limit of 0.05 n g/ μ L. The colorimetric PCR approach is a suitable point-of-care test for rapidly and accurately identifying M. catarrhalis . • First-time detection of Moraxella catarrhalis using the ompCD gene colorimetric approach. • A colorimetric PCR technique was optimized to detect M. catarrhalis both by the naked eye and quantitatively. • To examine the diagnosis, endpoint spectrophotometry at 450 and 570 nm was carried out. • The specificity and selectivity of the method were investigated using several bacterial and mixed samples. • A sensitivity of 0.05 n g/ μ L and 100% specificity was achieved.