Antimicrobial Peptides: Features, Action, and Their Resistance Mechanisms in Bacteria

Abstract

In recent years, because of increased resistance to conventional antimicrobials, many researchers have started to study the synthesis of new antibiotics to control the disease-causing effects of infectious pathogens. Antimicrobial peptides (AMPs) are among the newest antibiotics; these peptides are integral compounds in all kinds of organisms and play a significant role in microbial ecology, and critically contribute to the innate immunity of organisms by destroying invading microorganisms. Moreover, AMPs may encourage cells to produce chemokines, stimulate angiogenesis, accelerate wound healing, and influence programmed cell death in multicellular organisms. Bacteria differ in their inherent susceptibility and resistance mechanisms to these peptides when responding to the antimicrobial effects of AMPs. Generally, the development of AMP resistance mechanisms is driven by direct competition between bacterial species, and host and pathogen interactions. Several studies have shown diverse mechanisms of bacterial resistance to AMPs, for example, some bacteria produce proteases and trapping proteins; some modify cell surface charge, change membrane fluidity, and activate efflux pumps; and some species make use of biofilms and exopolymers, and develop sensing systems by selective gene expression. A closer understanding of bacterial resistance mechanisms may help in developing novel therapeutic approaches for the treatment of infections caused by pathogenic organisms that are successful in developing extensive resistance to AMPs. Based on these observations, this review discusses the properties of AMPs, their targeting mechanisms, and bacterial resistance mechanisms against AMPs.

Assessment of Susceptibility to Five Common Antibiotics and Their Resistance Pattern in Clinical Enterococcus Isolates

“…Over the past two decades, due to excessive consumption of antibiotics, resistance to common antibiotics has been increased (30)(31)(32). Accordingly, infections with methicillinresistant S. aureus (MRSA) and vancomycinresistant Enterococcus species (VRE) poses significant treatment challenges, which leads to an increase in treatment failure, relapse, and higher rates of mortality, as according to the reports mortality from enterococcal bacteremia is estimated at 15-35% (33).…”

Chemical Composition and Antibacterial Activity of the Essential Oils Extracted From 4 Medicinal Plants (Labiatae) of Kerman, Iran

“…The increasingly growing rate of bacteria resistance to the antibiotics requires developing and searching for new antimicrobial agents. 1 Compounds derived from the medicinal plants have gained widespread interest in respect to the search of alternative antibacterial agents. The reason is this perception exists that they are safe and have a long history of being used in folk medicine for treating infectious diseases.…”

“…As it mentioned, the increasing microbial resistance against antibiotics has naturally led to search for new antimicrobial agents. 1 Labiatae or Lamiaceae, also called as the mint family, is a family of flowering plants. The enlarged Labiatae contains about 236 genera and 6900-7200 species.…”

In Vitro Evaluation of Antibacterial Properties of Zinc Oxide Nanoparticles on Pathogenic Prokaryotes

“…Bacterial resistance to antibiotics has become a global problem nowadays. 1 In examining different options to solve this problem, nanomaterials, such as metal oxide nanoparticles, have appeared to be promising candidates during the last few years. As a result, the science of nanotechnology has significantly advanced due to its wide application.…”