Moraxella catarrhalis

**Semantic type:** Bacterium

**Definition:** A species of gram-negative, aerobic, oxidase-positive diplococcus bacteria within the phylum Proteobacteria that causes upper respiratory tract infections, particularly in immunocompromised hosts.

**Synonyms:** - Branhamella catarrhalis - Branhamella catarrhalis - M. catarrhalis - MORAXELLA CATARRHALIS