The role of anaerobes in human infections.

Anaerobic bacteria have been shown to play a role in infection of all types in humans. Certain infections are notable for the prominent role played by anaerobes; included are brain abscess, chronic sinusitis and otitis media, oral and dental infections, neck space infections, bite infections, lung abscess, aspiration pneumonia, empyema, intra-abdominal infections of all types (notably peritonitis, intra-abdominal abscess, and liver abscess), abdominal surgical wound infections, female genital tract infections of all types, various superficial and deep soft tissue infections, and osteomyelitis. In recent years, two new anaerobic infections have been appreciated-infant botulism and pseudomembranous colitis due to Clostridium difficile. Considerable progress has been made recently in delineating factors predisposing to anaerobic infections, virulence factors in anaerobes, and host defense mechanisms vs. these organisms. Taxonomic schemes for anaerobes have been improved and simplified considerably, as have techniques for growing and identifying anaerobic bacteria. Rapid procedures are coming into the picture. Finally, much has been learned about therapy of these infections. Although there has been some problem of increased resistance of anaerobes to antimicrobial agents, several promising new drugs are now available to offset this.