Potent cationic antimicrobial peptides against Mycobacterium tuberculosis in vitro

Background: Tuberculosis (TB) is known to be one of the 10 causes of global death by infectious agents. The increasing numbers of multiple antibiotic resistance (MDR-TB) and cases of extensive resistance to antibiotics (XDR-TB) have led to the development of new and effective TB therapy. Cationic antimicrobial peptides (CAMPs) have emerged in the research as a safe and effective treatment against a variable range of bacterial and fungi pathogens, including Mycobacterium tuberculosis (M. tuberculosis). Method: This study developed a new CAMP coupled with cinnamic acid derivatives, and studied the antimicrobial activity against clinical isolates of M. tuberculosis (H37Rv) and MDR-TB. Results: All modified CAMPs showed enhanced activity against both M. tuberculosis strains and were capable of disrupting heavy clumping of mycobacteria in culture. In addition, all modified CAMPs were able to substantially inhibit the intracellular growth of both strains at low concentrations. Conclusions: The characteristic proprieties of cinnamic acid + CAMP(n) successfully inhibited the growth of both clinical isolates M. tuberculosis and MDR-TB in vitro and have, for now, promising use as a drug adjuvant due to their effect on mycobacteria growth. (C) 2019 Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.