Choosing antimicrobials for anaerobic infections.

Anaerobes are opportunistic pathogens that are the predominant indigenous normal flora of the skin and mucous membranes in humans. Anaerobic infections are common, often found in proximity to their anatomical locations, and may be difficult to treat. Anaerobes are usually found in mixed culture along with aerobes. This article reviews the activity of various classes of antimicrobials used against anaerobes, along with their pharmacodynamics, and the susceptibility patterns and resistance mechanisms of important anaerobic pathogens such as Bacteroides fragilis. It is hoped that the reader will be able to use this information and synthesize it into an approach on how to select antimicrobials for anaerobic therapy.