Transcriptional Regulation and Functional Characterization of the Plasmid-Borne oqxAB Genes in Salmonella Typhimurium

Abstract

The transferable mechanisms of quinolone resistance (TMQR) gene, oqxAB , has been widely detected in Salmonella and is commonly associated with aac(6′)-Ib-cr . It is thought to be associated with fluoroquinolone resistance, while its ancestor gene from K. pneumoniae is not. This study evaluated the actual role of the plasmid-borne oqxAB genes in Salmonella and showed that it was not able to mediate intermediated resistance to fluoroquinolone and only did so when it coexisted with aac(6′)-Ib-cr .

Effect of Enrofloxacin on the Microbiome, Metabolome, and Abundance of Antibiotic Resistance Genes in the Chicken Cecum

“…The plasmid genes qnrA , qnrB , qnrD , and qnrS encode proteins of the pentapeptide repeat sequence family, which protect DNA gyrase and topoisomerase IV from FQ-mediated inhibition ( 11 ). FQ resistance can also result from its acetylation with an appropriate amino nitrogen target mediated by a variant of the common aminoglycoside acetyltransferase gene aac(6′)-Ib-cr ( 12 ). A third mechanism involves the plasmid-based efflux pump-encoding genes qepA ( 13 ) and oqxAB ( 12 , 14 ), which enhance FQ clearance.…”

“…FQ resistance can also result from its acetylation with an appropriate amino nitrogen target mediated by a variant of the common aminoglycoside acetyltransferase gene aac(6′)-Ib-cr ( 12 ). A third mechanism involves the plasmid-based efflux pump-encoding genes qepA ( 13 ) and oqxAB ( 12 , 14 ), which enhance FQ clearance. In addition, it has been reported that the use of enrofloxacin causes an increase in the abundance of antibiotic resistance genes (ARGs) encoding resistance to macrolide-lincosamide-streptogramin, aminoglycosides, and tetracyclines.…”