Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 33-14: Infections Caused by Moraxella Catarrhalis + Key Features Download Section PDF Listen +++ ++ An infection caused by a gram-negative aerobic coccus, Moraxella catarrhalis, which is morphologically and biochemically similar to Neisseria + Clinical Findings Download Section PDF Listen +++ ++ Sinusitis, bronchitis, otitis and, rarely, pneumonia Bacteremia and meningitis have also been reported in immunocompromised patients + Diagnosis Download Section PDF Listen +++ ++ Culture The organism frequently colonizes the respiratory tract, and differentiation of colonization from infection can be difficult If M catarrhalis is the predominant isolate, therapy should be directed against it + Treatment Download Section PDF Listen +++ ++ Amoxicillin-clavulanate, ampicillin-sulbactam, trimethoprim-sulfamethoxazole, ciprofloxacin, and second- and third-generation cephalosporins Treatment is similar to that for Haemophilus infections (see Haemophilus Infections) Typically produces beta-lactamase and, therefore, is usually resistant to ampicillin and amoxicillin