tailieunhanh - Báo cáo sinh học: "Antibacterial and resistance-modifying activities of thymoquinone against oral pathogens"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí y học Molecular Biology cung cấp cho các bạn kiến thức về ngành sinh học đề tài: Antibacterial and resistance-modifying activities of thymoquinone against oral pathogens. | Kouidhi et al. Annals of Clinical Microbiology and Antimicrobials 2011 10 29 http content 10 1 29 ANNALS OF CLINICAL MICROBIOLOGY AND ANTIMICROBIALS RESEARCH Open Access Antibacterial and resistance-modifying activities of thymoquinone against oral pathogens 1 1 3 2 1 2 Bochra Kouidhi Tarek Zmantar Hanene Jrah Yosra Souiden Kamel Chaieb Kacem Mahdouani and Amina Bakhrouf1 Abstract Background The presence of resistant bacteria in the oral cavity can be the major cause of dental antibiotic prophylaxis failure. Multidrug efflux has been described for many organisms including bacteria and fungi as part of their drugs resistance strategy. The discovery of a new efflux pump inhibitor could extend the useful lifetime of some antibiotics. Methods In this study the MICs of thymoquinone TQ tetracycline and benzalkonium chloride BC were determined in absence and in presence of a sub-MIC doses of thymoquinone 1 2 MIC . In addition the 4 6-diamidino-2-phenylindole DAPI efflux assay was carried out to determine the effect of TQ on DAPI cells accumulation. Results TQ induced a selective antimicrobial activity. Its synergic effect resulted in at least a 4-fold potentiation of the tested antibiotics and antiseptic. In addition TQ inhibited the DAPI efflux activity in a concentration-dependent manner. The rate of DAPI accumulation in clinical isolates was enhanced with TQ 0 to 200 pg ml . There is also a decrease in loss of DAPI from bacteria in the presence of TQ. The concentration causing 50 of DAPI efflux inhibition after 15 minutes was approximately 59 pg ml for Pseudomonas aeroginosa and 100 pg ml and Staphylococcus aureus respectively. Conclusions TQ possesses a selective antibacterial activity against oral bacteria. It is therefore suggested that TQ could be used as a source of natural products with resistance-modifying activity. Further investigation is needed to assess their clinical relevance. Background The human oral cavity is an habitat for about