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 33-31: Anaerobic Infections + Key Features Download Section PDF Listen +++ ++ Frequently occur in the setting of poor oral hygiene and periodontal disease, aspiration of saliva (which contains 108 anaerobic organisms per milliliter in addition to aerobes) May lead to necrotizing pneumonia, lung abscess, and empyema Polymicrobial infection is the rule Anaerobes are frequently isolated etiologic agents, particularly Prevotella melaninogenica Fusobacteria Peptostreptococci + Clinical Findings Download Section PDF Listen +++ ++ Fever Productive cough Night sweats Weight loss Chronic course of illness Poor dentition (frequently) + Diagnosis Download Section PDF Listen +++ ++ Pleural fluid culture Chest radiograph CT scan + Treatment Download Section PDF Listen +++ ++ Clindamycin, 600 mg intravenously once, followed by 300 mg every 6–8 hours orally, is the treatment of choice Metronidazole is an alternative But does not cover facultative streptococci, which are often present So, if used, a second agent active against streptococci, such as ceftriaxone, 1 g/day intravenously or intramuscularly should be added Penicillin, 2 million units every 4 hours intravenously, followed by amoxicillin, 750–1000 mg every 12 hours orally, is an alternative; however, penicillin-resistant Bacteroides fragilis and P melaninogenica are commonly isolated and have been associated with clinical failures Moxifloxacin, 400 mg once daily orally or intravenously may be used Because these infections respond slowly, a prolonged course of therapy (eg, 4–6 weeks) is generally recommended