Trichomonas vaginalis Metronidazole Resistance Is Associated with Single Nucleotide Polymorphisms in the Nitroreductase Genes ntr4 Tv and ntr6 Tv

Metronidazole resistance in the sexually transmitted parasite Trichomonas vaginalis is a problematic public health issue. We have identified single nucleotide polymorphisms (SNPs) in two nitroreductase genes ( ntr4 Tv and ntr6 Tv ) associated with resistance. These SNPs were associated with one of two distinct T. vaginalis populations identified by multilocus sequence typing, yet one SNP ( ntr6 Tv A238T), which results in a premature stop codon, was associated with resistance independent of population structure and may be of diagnostic value.