Moraxella Catarrhalis Infection

Key Features

• An infection caused by a gram-negative aerobic coccus, Moraxella catarrhalis, which is morphologically and biochemically similar to Neisseria

Clinical Findings

• Sinusitis, bronchitis, otitis and, rarely, pneumonia

• Bacteremia and meningitis have also been reported in immunocompromised patients

Diagnosis

• 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

• 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