Evidence for a novel bacteriophage from moraxella catarrhalis

Abstract

Moraxella catarrhalis is one of the major causes of RTI and otitis media, which was known as a harmless inhabitant of upper respiratory tract until 1980s. The knowledge on virulence factors, pathogenesis of this bacterium is scarce and the reason/(s) for recent pathogenic conversion of M. catarrhalis is/are not known. Several examples demonstrate that bacteriophages control bacterial virulence in almost every step of pathogenesis. Number of bacteriophages are known to be solely responsible from bacterial virulence. We hypothesize that a bacteriophage may be responsible for pathogenic conversion of M. catarrhalis, and we investigated whether a bacteriophage is present in M. catarrhalis. In this study, evidence for a bacteriophage from M.catarrhalis is presented. Supernatants of M.catarrhalis broth cultures were shown to cause bacterial cell lysis on soft agar cultures, indicating presence of bacteriophages released from them. Two particles having different morphologies and different size ranges (p<0. 05) were co-purified from these supernatants. One segment of dsDNA molecule and three segments of ssRNA molecules were extracted from these particles. The comparison between pathogenic and non-pathogenic strains of M.catarrhalis demonstrated marked differences in the quantity of these RNA and DNA molecules.Future studies are necessary to determine the origins of RNA and DNA molecules.