Abstract

Salmonella spp. is a worldwide distributed foodborne pathogen. In the last decade, Salmonella In- fans (SI) has been reported as an emergent serovar with high levels of muldrug resistance (MDR) in isolates from chicken meat, pork, humans, and the environment. Thus, biocontrol of MDR SI is crucial for food safety. Bacteriophages are viruses that infect only bacteria. Due to capability for cause lysis, phages are an alternave to target emergent MDR SI. Here, we evaluated genomic and phenotypic characteriscs of six phages that infect SI. Methods: We selected six phages (DR91, DR94, FD55, FD35, 4FA and RB01) from our library that infected SI (strain PUCV57). Phages were se- quenced by Illumina, annotated with Rask, their images were obtained with TEM. Addionally, we determined the host range, using 14 serovars of Salmonella spp., and evaluated their effect on 10 strains of SI with different resistant profiles. We selected RB01 to analyze the killing curve at MOI 10. Results: DR91, DR94, FD55, FD35 and 4FA were classified as Myoviridae, except DR91 that be- longs to the Siphoviridae family. Neither of the phages had genes associated with anbioc resis- tance, virulence or lysogeny. Host range results showed that DR091, DR094, FD55, FD35, 4FA and RB01 lyses, respecvely 13, 13, 6, 11, 8 and 12 different serovars of Salmonella spp., being DR91, DR94 and RB01 the phages with a broader host range. Addionally, DR091, DR094 and RB01 were able to lyses all evaluated MDR SI. FD55 and RB01 lyses 9, but phage FD55 cause paral lysis in 7 strains. Finally, we observed that RB01 inhibit the growth of MDR SI from the first to the seventh hour; and RB01 was capable to reduce in 1,23 log CFU/mL to strain tested. Significance: Genomic and phenotypic analysis of six phages idenfied phages DR091, DR094 and RB0 as possible candi- dates against MDR SI. Since the use of phages are an opon against MDR bacteria, it is necessary further studies to develop a cocktail against MDR SI.