[Incidence of anaerobic bacteria in respiratory tract infections].

Anaerobic bacteria are predominant components of normal oral cavity, upper respiratory tract, gastrointestinal, genital and skin flora. They are involved in infections such as pneumonia, aspiration pneumonia, lung abscess and empyema. Laboratory diagnosis of anaerobic infections is based on recovering the etiological agents from clinical materials. Appropriatte specimens include: pus, purulent fluid, biopsy specimen of lung, transtracheal aspirates and bronchoalveolar lavage (BAL). Lower respiratory infections are usually either polymicrobial or mixed anaerobic-aerobic infections. Peptostreptococcus, Fusobacterium, Prevotella and Bacteroides are the most common anaerobes. Anaerobic bacteria are susceptible to metronidazole, tinidazole (exception of Gram-positive rods), amoxicillin/clavulanate, ampicillin/sulbactam, piperacillin/tazobactam, imipenem and clindamycin. Treatment includes an antibiotics regimen with an agent active against anaerobic and aerobic bacteria (therapy with 2 or 3 antimicrobial drugs).