Antibiotic of Choice

Traditionally, penicillin alone was used and produced satisfactory results. Of late, there has been increasing incidence of penicillin resistance in oropharyngeal anaerobes. Hence, penicillin alone is no longer recommended. Metronidazole alone has failed despite its superb anaerobic spectrum due to lack of activity against microaerophilic streptococci which are significant pathogens in lung abscesses. Penicillin added to metronidazole is an acceptable alternative.

Clindamycin is the most popular antimicrobial for treatment of lung abscesses and has produced excellent results. The intracellular uptake of clindamycin and its stability in abscess which have low pH and poor vascularity may offer an advantage.

Other beta lactams such as ampicillin and sulbactam, ticarcillin or amoxicillin with clavulanate, piperacillin with tazobactam, cefoxitin and cefotetan also have excellent activity against anaerobes and offer expensive alternatives. Imipenem also has excellent activity against anaerobes. Presently, available quinolonoses such as ciprofloxacin, norfloxacin, oflaxacin, etc. have very poor activity against anaerobes and streptococci. Prolonged treatment over several weeks is typically required.