Open AccessMechanism of metronidazole‐resistance by isolates of nitroreductase‐producing Enterococcus gallinarum and Enterococcus casseliflavus from the human intestinal tract
Author(s) -
Rafii Fatemeh,
Wynne Rebecca,
Heinze Thomas M.,
Paine Donald D.
Publication year - 2003
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/s0378-1097(03)00513-5
Subject(s) - metronidazole , microbiology and biotechnology , nitroreductase , enterococcus faecalis , enterococcus , biology , antibacterial agent , bacteria , antibiotics , staphylococcus aureus , genetics
Enterococcus casseliflavus and Enterococcus gallinarum strains resistant to metronidazole, nitrofurantoin and nitrofurazone were isolated from fecal samples of a patient with recurrent ulcerative colitis treated with metronidazole. Unlike other metronidazole‐resistant bacteria, these strains produced nitroreductase but metabolized metronidazole to compounds that could not be detected by liquid chromatography with UV or mass spectral analysis. Metronidazole‐susceptible Clostridium perfringens grew equally well in spent cultures of Enterococcus spp. incubated with or without metronidazole. These data indicate that the nitroreductases produced by these Enterococcus strains did not activate metronidazole to bactericidal metabolites and these bacteria may reduce the effectiveness of metronidazole. We have indirect evidence for an alternative pathway that results in metronidazole resistance. These strains of enterococcus had nitroreductase so resistance should not have occurred.