An important health problem in Bolivia is foodborne and waterborne infections mainly due to poor agricultural practices. Among the most common infections are those of Salmonella spp., E. coli and Campylobacter jejuni. The Microbial Contaminant Surveillance Network (INLASA, 2017 - 2018 Newsletter of the Ministry of Health), reporting a prevalence of E. coli in 3% samples outside the Standard of microbiological quality of food, showing an antimicrobial resistance profile characterized by resistance to nitrofurantoin and nalidixic acid in more than 65% of the strains and resistance to ampicillin and cephalosporins in more than 70%. Bacteriophages have become an important tool for biotechnologists. Bacteriophages are viruses capable of infecting their bacterial host and have been considered a promise as biocontrol agents. Further, bacteriophages infect specific bacteria without any effect on normal microbiota and any side effects for applications. Bacteriophages have a number of advantages over other alternatives: (i) high efficacy in killing bacteria, (ii) minimal or no side effects, (iii) no allergic effects, (iv) production is fast and cheap, and (v) they are host-specific and therefore do not affect the intestinal microbiota or other saprophytic bacteria of the agricultural environment. Bacteriophage endolysins are dsDNA bacteriophage-encoded peptidoglycan hydrolases (PGHs) that are synthesized in phage-infected bacterial cells during the late phase of gene expression at the end of the multiplication cycle (Loessner,2005). Numerous studies have investigated the specificity of endolysins by assaying the cleavage sites on purified peptidoglycan. Generally, the structure of bacteriophage endolysins differs between those enzymes targeting Gram-positive and Gram-negative bacteria, reflecting the differences in the cell wall architecture between these major bacterial groups. In gram-negative cells, the presence of the outer membrane (OM) effectively prevents access by hydrophilic lytic enzymes. Moreover, catalytically, a single enzyme molecule should be sufficient to cleave an adequate number of bonds to kill a bacterium. Unlike other secretory enzymes, there are also signal-arrest-release (SAR) Gram-negative phage endolysins which are independent of holin-mediated endolysins. Signal-arrest-release (SAR) endolysins are not processed by signal peptidase and released into the periplasm but instead accumulate in a membrane-tethered form. Activation occurs when the enzyme is released from the membrane and refold into the catalytically active form. The goal of the present project is to obtain a new bacteriophage endolysins for biological control of food-borne bacterial pathogens or antimicrobial-resistance bacteria. To accomplish this goal, studies based on 1) Comparative analysis based on metagenomic and genomic data of bacteriophages-infecting-Salmonella, Campylobacter, and E. coli from birds and human fecal samples; 2) Shotgun identification and characterization of the cell wall binding domain (CBD) and signal-arrest and release endolysins domain (SAR) for biocontrol of gram-negative bacteria (Salmonella, E. coli, and Campylobacter) emphasizing the common bacteriophages sequences found in both human and bird fecal samples, must be done. Finally, the synthesis and design of endolysins with specific anti-microbial activity against gram-negative bacteria (Salmonella, E.coli, and Campylobacter) by genetic engineering.