Inducible NorA-mediated multidrug resistance in Staphylococcus aureus

Inducible clindamycin resistance among Staphylococcus aureus isolates

Introduction: Clindamycin is considered an useful alternate drug in penicillin-allergic patients in the treatment of skin & soft tissue infections caused by Staphylococcus aureus. Staphylococcus spp. can be resistant to erythromycin through either erm or msr A genes. Strains with erm-mediated erythromycin resistance may possess inducible clindamycin resistance but may appear susceptible to clin...

Quinolone susceptibility of norA-disrupted Staphylococcus aureus.

The MIC of norfloxacin for the norA-disrupted mutant termed RDN1, obtained from quinolone-susceptible Staphylococcus aureus RN4220, was eightfold lower than that for RN4220. The increase in susceptibility was related to an increase of drug accumulation by RDN1. These results indicate that NorA plays an important role in the susceptibility of quinolone-susceptible S. aureus to selected quinolones.

Methicillin resistance & inducible clindamycin resistance in Staphylococcus aureus

BACKGROUND & OBJECTIVES Methicillin resistant Staphylococcus aureus (MRSA) isolates with inducible clindamycin resistance (iCR) are resistant to erythromycin and sensitive to clindamycin on routine testing and inducible clindamycin resistance can only be identified by D-test. This study was aimed to detect methicillin resistance and iCR among S. aureus isolates, effectiveness of some commonly u...

A mutation in the 5' untranslated region increases stability of norA mRNA, encoding a multidrug resistance transporter of Staphylococcus aureus.

NorA, a multidrug efflux pump in Staphylococcus aureus, protects the cell from multiple drugs, including quinolones. The flqB mutation (T-->G) in the 5' untranslated region upstream of norA causes norA overexpression of 4.9-fold in cis, as measured in norA::blaZ fusions. The transcriptional initiation site of norA was unchanged in mutant and wild-type strains, but the half-life of norA mRNA was...

Staphylococcus aureus Efflux Transporter Distinct from NorA in Evidence for the Existence of a Multidrug