Antibiotic adjuvants: Diverse strategies for controlling drug-resistant pathogens

Abstract

The growing number of bacterial pathogens that are resistant to numerous antibiotics is a cause for concern around the globe. There have been no new broad-spectrum antibiotics developed in the last 40 years, and the drugs we have currently are quickly becoming ineffective. In this article, we explore a range of therapeutic strategies that could be employed in conjunction with antibiotics and may help to prolong the life span of these life-saving drugs. Discussed topics include antiresistance drugs, which are administered to potentiate the effects of current antimicrobials in bacteria where they are no longer (or never were) effective; antivirulence drugs, which are directed against bacterial virulence factors; host-directed therapies, which modulate the host's immune system to facilitate infection clearance; and alternative treatments, which include such therapies as oral rehydration for diarrhea, phage therapy, and probiotics. All of these avenues show promise for the treatment of bacterial infections and should be further investigated to explore their full potential in the face of a postantibiotic era. Global incidence of antimicrobial resistance is increasing so there is a great need to prolong the lives of our antibiotics. We review drugs that can be taken in conjunction with antibiotics, or antimicrobial adjuvants. Such therapeutics can increase the effectiveness of antibiotics, target bacterial virulence factors, modulate the immune system to help clear bacterial infections or act via a diverse range of alternative methods. These treatments show great promise and should be further investigated to prevent a post-antibiotic era.