The present invention provides compositions and methods useful for detecting Moraxella catarrhalis. The compositions are antibodies, proteins or nucleic acid sequences specific to Moraxella catarrhalis (M. catarrhalis). The method comprises the steps of obtaining a biological sample from an individual and detecting within the biological sample the presence of proteins, nucleic acid sequences and lipooligosaccharides (LOS) specific to Moraxella catarrhalis. Further, compositions and methods useful for distinguishing between M. catarrhalis serotypes are provided.