The emergence of metronidazole-resistant <i>Prevotella bivia</i> harboring <i>nimK</i> gene in Japan

Metronidazole (MTZ) is an important antimicrobial agent in anaerobic infections and is widely used in clinical settings. The rate of MTZ resistance in anaerobic bacteria has been increasing in recent years, and the <i>nim</i> gene (nitro-imidazole reductase) is one of the resistance mechanisms. <i>Prevotella bivia</i> is found in humans in the urinary tract and vagina and is known to cause infections in some cases. One of the <i>nim</i> genes, <i>nimK</i>, has recently been discovered in this species of bacteria, but there are no reports of antimicrobial resistance (AMR)-related regions in its whole genome level. In this study, we analyzed the AMR region of <i>nimK</i>-positive <i>P. bivia</i> derived from clinical specimens based on comparisons with other anaerobic genomes. <i>P. bivia</i> was found to be engaged in horizontal gene transfer with other anaerobic bacteria, and the future spread of the <i>nimK</i> gene is a concern.