Stydy on Mechanism of Resistance to Fluoroquinolones by norA-Mediated in Staphylococcus aureus

摘要

Objective To study mechanism of Resistance to fluoroquinolones by norA-Mediated in S.aureus. Methods The Dig-labbled norA gene probe was made by PCR; norA gene and the transcription of norA gene of sensitives, resistances and induced resistant strai nwere studied by Dot plot hybridization and Slot plot hybridization, respectively. Results norA gene is detected in all S.aureus studied; The level of transcription of norA gnee in induced resistant strain SA2-16 is higher than that of its parent; The level of transcription of norA gene in sensitive organisms are same as resistant strains'. The level of transcription of norA gene in strains grown in 1/10 are not different with that of strains grown in normal LB. Conclusion no rA gene may be normal gene in S. aureus; The reason of enhanced hydrophilic fluoroquinolones efflux is the increasing of transcription of norA gene; This reisstance mechanism mediated by norA gene is not exist in every strains.