The nature and epidemiology of OqxAB, a multidrug efflux pump

Abstract

Background OqxAB efflux pump has been found to mediate multidrug resistance (MDR) in various bacteria over the past decades. The updates on the nature and epidemiology of OqxAB efflux pump need to be fully reviewed to broaden our understanding of this MDR determinant. Methods A literature search using the keyword of “oqxAB” was conducted in the online databases of Pubmed and ISI Web of Science with no restriction on the date of publication. The 87 publications were included into this review as references due to their close relevance to the nature and/or epidemiology of OqxAB efflux pump. Results The oqxAB gene generally locates on chromosome and/or plasmids flanked by IS26-like elements in clinical isolates of Enterobacteriaceae and Klebsiella pneumoniae , conferring low to intermediated resistance to quinoxalines, quinolones tigecycline, nitrofurantoin, several detergents and disinfectants (benzalkonium chloride, triclosan and SDS). It could co-spread with other antimicrobial resistance genes ( bla CTX-M , rmtB and aac(6′)-Ib etc.), virulence genes and heavy metal resistance genes ( pco and sil operons). Both RarA (activator) and OqxR (repressor) play important roles on regulation of the expression of OqxAB. Conclusions The dissemination of oqxAB gene may pose a great risk on food safety and public health. Further investigation and understanding of the natural functions, horizontal transfer, and regulation mechanism of the OqxAB efflux pump will aid in future strategies of antimicrobial usage.

<p>Emergence of NDM-5-Producing Carbapenem-Resistant <em>Klebsiella pneumoniae</em> and SIM-Producing Hypervirulent <em>Klebsiella pneumoniae</em> Isolated from Aseptic Body Fluid in a Large Tertiary Hospital, 2017–2018: Genetic Traits of <em>bla</em>NDM-Like and <em>bla</em>SIM-Like Genes as Determined by NGS</p>

“…As oqxA only can confer low-level resistance to quinolones, hvKP carrying oqxA may be susceptible to quinolones. 17 Moreover, SIM-producing hvKP strain was still susceptible to cephalosporins and monobactams antibiotics in our study. Additionally, fosA2 gene was only explored in hvKP strain.…”

“…16 Therefore, analyzing the local data can aid in optimizing the future strategies of antimicrobial usage and providing meaningful guidance to the clinical practice. 17 The virulence factors of KP lead to high mortality and enhance the difficulty of treatment. Most of the studies classified the virulence genes as four major classes, including type I and type III fimbriae, lipopolysaccharide, siderophore iron uptake systems, and a polysaccharide capsule.…”

Whole genome sequencing snapshot of multi-drug resistant Klebsiella pneumoniae strains from hospitals and receiving wastewater treatment plants in Southern Romania

“…The most prevalent were the oqxA/B complex genes conferring resistance to multiple classes of antibiotics, but also to detergents and disinfectants. The oqxA/B complex can be located on chromosome and/or plasmids, flanked by IS26-like elements, posing thus a great risk for the public and environmental health, in terms of AMR horizontal transmission and selection of multiple-drug resistant phenotypes [71].…”

An Intertwined Network of Regulation Controls Membrane Permeability Including Drug Influx and Efflux in Enterobacteriaceae

“…Besides acrRAB , the chromosome of K. pneumoniae contains another recently characterized locus, rarA-oqxABR , encoding an efflux system together with its regulatory elements [ 61 ]. The pump OqxAB is associated with resistance to quinoxalines, quinolones, tigecycline, nitrofurantoine, chloramphenicol [ 62 ]. RarA is an AraC-type transcriptional regulator that is overproduced as OqxAB when the negative regulator OqxR does not work [ 51 , 63 , 64 ].…”

“…Under the clusters of orthologous groups functional classification, the majority of affected genes belonged to the family of cell envelope biogenesis and post-translational modification, along with genes encoding previously uncharacterized transport proteins and the porin OmpK35 [ 65 ]. RarA is active in Klebsiella, Enterobacter, and Serratia, and is proposed to be the most effective positive effector of the Klebsiella MDR after RamA [ 62 ].…”