CRISPR-Cas9 mediated phage therapy as an alternative to antibiotics

Abstract

Inappropriate use of antibiotics is globally creating public health hazards associated with antibiotic resistance. Bacteria often acquire antibiotic resistance by altering their genes through mutation or acquisition of plasmid-encoding resistance genes. To treat drug-resistant strains of bacteria, the recently developed CRISPR-Cas9 system might be an alternative molecular tool to conventional antibiotics. It disables antibiotic-resistance genes (plasmids) or deactivates bacterial virulence factors and sensitizes drug-resistant bacteria through site-specific cleavage of crucial domains of their genome. This molecular tool uses phages as vehicles for CRISPR-cas9 delivery into bacteria. Since phages are species-specific and natural predators of bacteria, they are capable of easily injecting their DNA to target bacteria. The CRISPR system is packaged into phagemid vectors, in such a way that the bacteria containing the antibiotic-resistance plasmid sequence or that containing specific DNA sequences were made to be targeted. Upon CRISPR delivery, Cas9 is programmed to recognize target sequences through the guide RNA thereby causing double-strand cleavage of targeted bacterial DNA or loss of drug resistance plasmid, which results in cell death. Remarkably, the safety and efficacy of this newly developed biotechnology tool and the biocontrol product need to be further refined for its usage in clinical translation.

Pharmacokinetics and Biodistribution of Phages and their Current Applications in Antimicrobial Therapy

“…[ 38–41 ] Genetic approaches include phage‐mediated CRISPR‐Cas9 delivery to inactivate antimicrobial resistance genes, expression of antimicrobial peptides, and engineered receptor‐binding proteins to alter host ranges. [ 31,34–37,42–45 ]…”

“…[38][39][40][41] Genetic approaches include phage-mediated CRISPR-Cas9 delivery to inactivate antimicrobial resistance genes, expression of antimicrobial peptides, and engineered receptor-binding proteins to alter host ranges. [31,[34][35][36][37][42][43][44][45] continually within the host cell, causing release of virions without lysis. [8] Despite commonalities in their basic architecture and replicative mechanisms, phages are found in various shapes (tailed, filamentous, and polyhedral) and sizes (20-200 nm) and have different genomic organizations and specificities for bacterial hosts.…”

“…[38][39][40][41] There have also been recent advancements in CRISPR-Cas-mediated phage therapy as a novel precision medicine that can disable antibiotic resistance genes in specific bacterial strains. [42][43][44][45] These recent developments show how phages are modular engineering platforms that may enable diverse antibacterial mechanisms.…”

“…Phage capsid proteins can serve as scaffolds to chemically conjugate small molecules or nanoparticles, which can be activated to kill bacteria [38][39][40][41]. Genetic approaches include phage-mediated CRISPR-Cas9 delivery to inactivate antimicrobial resistance genes, expression of antimicrobial peptides, and engineered receptor-binding proteins to alter host ranges [31,[34][35][36][37][42][43][44][45].…”

In vitro antimicrobial activity evaluation of selected medicinal plants against multidrug- resistant isolate of Clinical Bovine Mastitis

“…As a result, treatment failure in dairy mastitis remains to be the main challenge affecting the development of the dairy industry in Ethiopia. As part of global efforts against multi-drug resistant pathogens utilizing biochemical and molecular tools of drug discovery [29,30], investigating the antimicrobial activity of the most used locally available medicinal plants against antibiotic-resistant isolates from clinical mastitis is very important. In this regard we used S. aureus and E. coli for the reason that these two test bacteria are the common bacterial isolate that has been reported to develop drug resistance [7-9, 31, 32].…”