Although plasmid-mediated quinolone resistance (PMQR) was thought not to exist before its discovery in 1998, the past decade has seen an explosion of research characterizing this phenomenon. The best-described form of PMQR is determined by the qnr group of genes. These genes, likely originating in aquatic organisms, code for pentapeptide repeat proteins. These proteins reduce susceptibility to ...

The in vitro antimicrobial activities of oxolinic acid, flumequine, sarafloxacin, enrofloxacin, and oxytetracycline against strains of bacteria pathogenic to fish (Aeromonas salmonicida subsp. salmonicida, atypical A. salmonicida, Vibrio salmonicida, Vibrio anguillarum, and Yersinia ruckeri) were determined at two different incubation temperatures, 4 and 15 degrees C, by a drug microdilution me...

Although quinolones have been in clinical use for decades, the mechanism underlying drug activity and resistance has remained elusive. However, recent studies indicate that clinically relevant quinolones interact with Bacillus anthracis (Gram-positive) topoisomerase IV through a critical water-metal ion bridge and that the most common quinolone resistance mutations decrease drug activity by dis...