Detection of resistance to the antibiotic metronidazole in C. difficile often requires the presence of heme in the media, for unclear reasons. Here, the authors show that most metronidazole-resistant strains carry a mutation that promotes expression of a heme-dependent enzyme that degrades nitroimidazoles, and the mutation often co-occurs with an amino-acid substitution in DNA gyrase that confers resistance to another class of antibiotics, fluoroquinolones.
- Abiola O. Olaitan
- Chetna Dureja
- Julian G. Hurdle
