The qnrB gene is one of several qnr alleles (often found on Enterobacteriaceae plasmids) that confer similar protective resistance to quinolones. qnrB-positive strains typically show modest increases in quinolone MICs, which can complicate therapy especially in serious infections. Detection of qnrB in a pathogen indicates a potential to survive fluoroquinolone therapy and select high-level mutants (Strahilevitz et al. 2009, Jacoby et al. 2014, Rodriguez-Martines et al. 2016).
Strahilevitz, J., Jacoby, G. A., Hooper, D. C., & Robicsek, A. (2009). Plasmid-mediated quinolone resistance: a multifaceted threat. Clinical microbiology reviews, 22(4), 664–689.
Jacoby, G. A., Strahilevitz, J., & Hooper, D. C. (2014). Plasmid-mediated quinolone resistance. Microbiology spectrum, 2(5), 10.1128/microbiolspec.PLAS-0006-2013.
Rodríguez-Martínez, J. M., Machuca, J., Cano, M. E., Calvo, J., Martínez-Martínez, L., & Pascual, A. (2016). Plasmid-mediated quinolone resistance: Two decades on. Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy, 29, 13–29.
