Isolamento e caracterização de bacteriófagos líticos para duas espécies de enterobatérias: salmonella esterica subespécie enterica e shigella sonnei

Abstract

Bacteriophages are viruses that only infect bacteria, do not interact with human cells and are the most abundant microorganisms on the planet. The use of phages has been considered as an alternative measure for the treatment of bacterial infections, mainly against multiresistant antibiotic strains. Salmonella and Shigella are enteropathogens commonly spread by water and food contaminated with fecal material; have a very large intestinal epithelial invasion power, being the most common causes of bacillary dysentery. The present work aimed to isolate and characterize lytic bacteriophages against Salmonella and Shigella strains. The bacteriophages were isolated from water sources, contaminated with domestic effluents, in the city of Manaus- Am. Two serovars of Salmonella enterica subspecies enterica and shigella sonnei were used as hosts for the isolation of species-specific phages; however, their respective infection capabilities have also been analyzed for other bacteria. The isolated phages were analyzed for the nature of their genetic material, infection cycle, morphology and stability. Altogether five lytic bacteriophages were isolated, from Salmonella Typhi, Salmonella Enteritidis and Shigella sonnei, all bacteriophages were able to infect at least ten other bacterial strains; the curves showed the relationships between different ranges of multiplicity of infection (MOI), and determined that the isolated viruses have a relatively low latency period, with releases of high amounts of new viral particles in the "busrt size", the transmission electron microscopy revealed that four of the phages belong to the family Siphoviridae, while a single phage has characteristics of Myoviridae; in the analysis of the genetic material it is not possible to differentiate the phages isolated for S. sonnei by RFLP, however all the other phages had different digestion profiles with the restriction enzymes used. The new phage characterized, in the present work, have promising characteristics to infect and generate lysis not only in host bacteria, but in other species of enterobacteria.