Molecular basis of metronidazole resistance in pathogenic bacteria and protozoa.

The molecular basis of metronidazole resistance has been examined in anaerobic bacteria, such as Bacteroides, Clostridium, and Helicobacter, and anaerobic parasitic protists such as Giardia, Entamoeba, and trichomonads. A variety of enzymatic and cellular alterations have been shown to correlate with metronidazole susceptibility in these pathogens; however, a common theme has been revealed. Resistant cells are typically deficient in drug activation. The frequent correlation between metronidazole resistance and ineffective drug activation suggests that drug resistance is the result of modification of proteins involved in drug activation. Copyright 1999 Harcourt Publishers Ltd.