Antimicrobial Peptides as a Promising Therapeutic Strategy for Neisseria Infections.

Antibiotic resistance is already widespread in the world, and it has become a great health problem. Therefore, comprehensive efforts are needed to minimize the resistance. The exploration of alternative therapies may offer a more targeted approach with less susceptibility to resistance. Even though antimicrobial peptides (AMPs) have been introduced as emerging antibiotic sources, they are not widely discussed in the literature. Since Neisseria infections show resistance to different types of antibiotics, the purpose of this review was to discuss the currently investigated AMPs with anti-Neisseria properties. In the present review, we provide an overview of 24 AMPs with in vitro anti-Neisseria properties.

Antimicrobial peptides as a promising treatment option against Acinetobacter baumannii infections.

BACKGROUND: With the increasing rate of antibiotic resistance in Acinetobacter, the World Health Organization introduced the carbapenem-resistant isolates in the priority pathogens list for which innovative new treatments are urgently needed. Antimicrobial peptides (AMPs) are one of the antimicrobial agents with high potential to produce new anti-Acinetobacter drugs. This review aims to summarize recent advances and compare AMPs with anti-Acinetobacter baumannii activity. METHODS: Active AMPs against Acinetobacter were considered, and essential features, including structure, mechanism of action, anti-A. baumannii potent, and other prominent characteristics, were investigated and compared to each other. In this regard, the Google Scholar search engine and databases of PubMed, Scopus, and Web of Science were used. RESULTS: Forty-six anti-Acinetobacter peptides were identified and classified into ten groups: Cathelicidins, Defensins, Frog AMPs, Melittin, Cecropins, Mastoparan, Histatins, Dermcidins, Tachyplesins, and computationally designed AMPs. According to the Minimum Inhibitory Concentration (MIC) reports, six peptides of Melittin, Histatin-8, Omega76, AM-CATH36, Hymenochirin, and Mastoparan have the highest anti-A. baumannii power against sensitive and antibiotic-resistant isolates. All anti-Acinetobacter peptides except Dermcidin have a net positive charge. Most of these peptides have alpha-helical structure; however, ß-sheet and other structures have been observed among them. The mechanism of action of these antimicrobial agents is divided into two categories of membrane-based and intracellular target-based attack. CONCLUSION: Evidence from this review indicates that AMPs would be likely among the main anti-A. baumannii drugs in the post-antibiotic era. Also, the application of computer science to increase anti-A. baumannii activity and reduce toxicity could be helpful.

Potent and selective inhibitors of class A ß-lactamase: 7-prenyloxy coumarins.

Class A and D ß-lactamases are the main causes of resistance against ß-lactam antibiotics, especially the penam group, in Staphylococcus aureus. On the basis of the potentiator property of ethanolic extracts of Ferula szowitsiana root on penicillin, MIC values observed for resistant S. aureus, the main naturally occurring compounds in these extracts, auraptene, umbelliprenin and galbanic acid, were evaluated for ß-lactamase inhibitory activity. Amongst them auraptene showed the most potent inhibitory activity (IC50=21±1.5 µM) toward class A ß-lactamase, whereas no inhibition was observed for class D ß-lactamase. To obtain the structure activity relationship of the mentioned compounds and rationalize the enzyme inhibitory results, docking analysis was performed for both groups of ß-lactamases. Docking analysis showed that the compounds have 100-500-fold lower bonding affinity toward the class D ß-lactamase than toward the class A enzyme.