Screening of Natural product as an efflux pump inhibitor and synthesis of its antibiotics conjugates: a novel approach to treat MDR strains

Bacteria acquire resistance to different classes of antibiotics through various mechanisms. Among these, the upregulation of efflux pumps plays a key role in multidrug resistance. Thus, the problem is addressed by screening and using natural product-antibiotic conjugates against MDR Staphylococcus . Out of the screened natural products, the blue pigment was showed an excellent efflux pump inhibitory activity in Staphylococus aureus ATCC 6538, which again proved by fluorescence emission and real time efflux assay. The MIC of the blue pigment was found to be 64 µg/ml however, the conjugates of blue pigment with ciprofloxacin and penicillin enhanced the antibacterial activity by 1.5 to 1.9 fold respectively, against S. aureus . The synthesis of conjugates were confirmed by UV-visible spectroscopic analysis. Overall, the present study highlights the potential of blue pigment derived from Streptomyces as an efflux pump inhibitor, and its conjugates with antibiotics could offer a better option for tackling multidrug-resistance bacteria.