Moraxella catarrhalis
（重定向自Micrococcus catarrhalis）
![Antibiotic sensitivity test. This strain shows resistance to ampicillin because it produces the enzyme β-lactamase. This is confirmed by the disc labelled β turning red.](/Images/godic/202501/27/M._cat_BSAC5640.JPG")
Moraxella catarrhalis is a fastidious, nonmotile, Gram-negative, aerobic, oxidase-positive diplococcus that can cause infections of the respiratory system, middle ear, eye, central nervous system, and joints of humans. It causes the infection of the host cell by sticking to the host cell using a Trimeric Autotransporter Adhesins (TAA).