Inhibition of Targeted Bacterial Growth Using MazF-Expressing Phagemids: A Novel Therapeutic Approach Based on Endoribonuclease Toxin Molecules.

The extensive and indiscriminate use of antibiotics, which are intended to halt bacterial growth or eliminate them, has unintentionally given rise to antimicrobial resistance (AMR), which is a critical threat to global health. In the pursuit of alternative solutions, researchers have focused on type II toxin-antitoxin systems prevalent within the bacterial domain. One such promising example is the MazF toxin, which has been demonstrated to cleave RNA at specific sequences. MazF toxins are now recognized as present in a diverse range of bacterial species and exhibit varying cleavage sequence specificities. This diversity offers the potential for controlling bacterial growth by silencing the expression of hundreds of essential genes. In this study, a preliminary screening of five MazF homologs from distinct taxonomic groups was conducted to identify a MazF candidate that can effectively suppress bacterial proliferation. MazFne1, an endoribonuclease toxin originating from Nitrosomonas europaea that specifically targets UGG sequences, emerged as a promising candidate. Building upon this discovery, a phagemid system was engineered to deliver mazFne1 and express it in two distinct Escherichia coli strains. This approach successfully inhibited E. coli growth, suggesting a potential strategy for developing therapeutic interventions to combat antibiotic-resistant bacterial infections.