Studying the role of different genes involving in vitro-induced multidrug resistance of Staphylococcus aureus

Abstract

In this study, we examined gyrB, grlB which involve in flouroquinolone resistance (FQ) and norA, mecA which relate to multidrug resistance in S.aureus. Genomic DNA of seven S. aureus strains (CIP-, LEV,-OFL resistant and CIP-, LEV-, OFL- revertant of S.aureus strains) were extracted and amplified by conventional PCR. Sequencing results showed no mutation in QRDR of grlB.In QRDR of gyrB gene, a substitution mutation has revealed at Thr451 to Ser (ACG  UCG) of all bacterial strains without of CIP-revertant. Additionally, mutation at Arg450 to Ser (AGA  AGU) was also detected in QRDR of CIP±resistantstrain. The mutation at Ala328 has been substituted by Gly(GCA  GGA) innorA coding region of CIP-, LEV- , OFL-resistant and OFL-revertant strains. Results of our study demonstrate that emergence of invitro-induced multidrug resistant S. aureus is resulted of multi- mutation presenting in particular genes. Keywords: S.aureus, multidrug resistance, in vitro, gyrB, grlB, norA, MecA.