Conversion Of Antibiotic Resistance In Methicillin-resistant Staphylococcus Aureus By Blocking MecR1 And BlaR1 Signal Pathways With DNAzymes

AIM: Staphylococcus aureus is a common pathogen causing serious hospital infections and community acquired infections and is also the pathogen with the highest drug resistant incidence. It is very high that the death rate of patients infected MRSA (Methicillin-resistant Staphylococcus aureus). But there is no specific and selective antibacterial agents to kill MRSA. The last treatment option is vancomycin. However, clinical isolations of vancomycin-resistant S. aureus were reported one after another in the United States, France, Australian and this situation is more and more serious. So it is evident and urgent to seek a new defending strategy against MRSA now. The resistance is due to acquiring drug-resistant gene mecA and blaZ, which encode PBP2a and β-lactamase, respectively. Transcription of mecA is regulated by the sensor-transducer proteins, MecR1 and its partner repressor, MecI. Similarily, transcription of blaZ is regulated by BlaR1 and BlaI. In our experiment, in order to restore the susceptibility of MRSA to oxacillin, we block resistant signal pathways in MRSA by PS-deoxyribozymes, which target mecR1 mRNA or blaR1 mRNA.METHODS:...