Abstract
The increasing use of antiseptic compounds creates selective pressure cause emergence of antiseptic resistance among Staphylococcus aureus .Resistance mechanism of antiseptic is driven mainly by multi drug resistant (MDR) efflux protein.Sixty five isolates of S.aureuswere collected from different clinical sources and subjected to 11 antibiotics most of them are recognized by efflux systems as extruded substrates. Range of efflux activity was estimated using cartwheel method. Simultaneous discrimination of antiseptic coding genes (qacA/B, smr and norA)as well as nuc and mecA genes among multidrug resistantS.aureus(MRSA) isolates was preformed using multiplex PCR assay , 61 isolatesamong 65 were positive tonucand mecA genes, 58 of them were positive to norA, 14 of them were positive to qacA/B and only two were positive to smr. All isolates detected with qacA/B characterized by fluoroquinolones resistant and most of them show strong efflux activity at cartwheel assay, all of the 14 isolates positive qacA/B were sequenced to differentiate between variants depending on position 323 (aspartic in QacA, alanine in QacB), 3 of them harbored asparagines amino acid at position 323 and considered to be a new variants that reported for the first time.
Highlights
The increasing use of antiseptic compounds creates selective pressure cause emergence of antiseptic resistance among Staphylococcus aureus .Resistance mechanism of antiseptic is driven mainly by multi drug resistant (MDR) efflux protein.Sixty five isolates of S.aureuswere collected from different clinical sources and subjected to 11 antibiotics most of them are recognized by efflux systems as extruded substrates
Plasmid encoded proteins Quaternary Ammonium Compunds (QacA) and (QacB)(4) and Small Multidrug resistance family(smr) [5] .Effluxes machinery belong to major facilitator superfamily (MFS) and small multi drug resistance family (SMR) family that uses secondary transporting system depend on ion moving (H+, K+) in electrochemical concentration gradients called proton motive force as energy source involved in transporting substrate from inside bacteria cell to surrounding environment to reduc intracellular concentration of toxic compound(1, 6,7)
Vol.16(3)2019 [6,14], qacA and qacB are called qacA/B genes since they share high homology [5],some early observations hypothesized that plasmid basedantiseptic resistance can be found as part of S.aureus chromosome since it is harbored by transposon [6].Biocides resistance in S.aureus contributed by smr; historically known which confers resistance to some quaternary ammonium compound and ethidium bromide [15,6].As far as we know, the current study is the first report that was investigated the occurrence of antiseptic resistance determinates among Methicilin Resistant Staphylococcus aureus (MRSA) isolates collected from different clinical cases
Summary
The increasing use of antiseptic compounds creates selective pressure cause emergence of antiseptic resistance among Staphylococcus aureus .Resistance mechanism of antiseptic is driven mainly by multi drug resistant (MDR) efflux protein.Sixty five isolates of S.aureuswere collected from different clinical sources and subjected to 11 antibiotics most of them are recognized by efflux systems as extruded substrates. The multi-drug resistance (MDR) pattern efflux pump that belongs to efflux family when consists of different number of monomers, 4 segments (Smr), 12 segments flouroquinoline efflux transporter protein (norA) and 14 segment (QacA, QacB) called transmembrane helices[8,9].Efflux pump is classified as one of the mechanisms contributes to MDR phenotype in methicillin resistant S.aureus since resistance of antibioticsbiocides is interface [10].Chromosomal active efflux mediated by NorA extrude multiple targets included quaternary ammonium compounds (tetraphenylphosphonium bromide, cetrimide, benzelkonium chloride), fluoroquinolones antibiotics (Norfloxacin, enoxacin, ofloxacin, ciprofloxacin) and intercalating dyes[11,12] and [13]. the chromosomal NorA transporter possesses higher recognizing target ability than plasmid based effluxes, QacA/B efflux pump with 14 ɑ-helix transmembrane segments displayed exceptionally wide range of substrate specificity, qacA shared great homology; genetic resemblance with qacB which distorted in 6 positionS only Single nucleotide polymorphisms (SNPs) at codon 323 provide non-conserved change in amino acid (Aspartic in QacA protein to Alanine in QacB protein) which clarifies their specificity differences. Baghdad Science Journal [6,14], qacA and qacB are called qacA/B genes since they share high homology [5],some early observations hypothesized that plasmid basedantiseptic resistance can be found as part of S.aureus chromosome since it is harbored by transposon [6].Biocides resistance in S.aureus contributed by smr; historically known (qacC, ebrand qacD) which confers resistance to some quaternary ammonium compound and ethidium bromide [15,6].As far as we know , the current study is the first report that was investigated the occurrence of antiseptic resistance determinates among Methicilin Resistant Staphylococcus aureus (MRSA) isolates collected from different clinical cases
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