Comparative genomics and antimicrobial activity of recombinant phage endolisins against multi-resistant gram-negative bacteria

Abstract

Gram-negative bacteria such as Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., Salmonella and Helicobacter pylori are multiresistant bacteria of clinical interest. Recombinant phage endolysins therefore appear as potential new antimicrobials to combat infections caused by antibiotic-resistant Gram-negative bacteria. Endolysins target the peptidoglycan layer, highly conserved structure that maintains the integrity of bacterial cells. Studies show that the main barrier to exogenous application of endolysins against Gram-negative bacteria is the low permeability of the lipopolysaccharide membrane. Thus, the aim of the present project is to unravel the evolutionary markers selected in the association of phage-endolysin-host ecology in Gram-negative bacteria of clinical interest and to evaluate the antimicrobial activity of broad-spectrum modified endolysins against multiresistant Gram-negative bacteria. Broad-spectrum endolysins will be selected, modified and cloned by comparing the evolutionary rate of species-specific bacteriophage-encoded phage endolysins to the selected bacteria. The antibacterial activity of purified enzymes will be evaluated in vitro and in vivo models of Galleria mellonella and/or BALB/c mice in the presence and absence of permeabilizing agents. This project presents as innovation the search for broad spectrum phage endolysins against multiresistant Gram-negative bacteria by selecting appropriate protein motifs and/or mutation and construction of genetically modified enzymes for exogenous action as possible alternative treatments to infections caused by antibiotic resistant bacteria. (AU)