Detectives with tail (Bacteriophages) explain the diversity of Salmonella in animal systems in Chile. IS017 D Rivera1, V Toledo2, F Dueñas2, R Tardone2, C Hamilton-West2, C salazar2, D Peñaloza2, C Cáceres, P Soza2, A Moreno Switt2. 1 Escuela de Medicina Veterinaria. Universidad Andrés Bello, Santiago. Chile. 2 Departamento de Medicina Preventiva. Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile. Santiago. Chile. email: dacil.rivera@gmail.com INTRODUCTION Phages are the most abundant entities on the Earth, estimated in a magnitude of 1031. They also have a small genome, but always retaining the most successful genes for their evolution along with their host (Reyes et al, 2012). In order to explain the diversity of a system, it is very interesting to understand their presence and distribution, since they are considered excellent reporters of environments . Phages are biological entities very specific to their host, so their presence in the system is a reliable indicator of the presence of the host, which for our model corresponds to Salmonella. OBJECTIVE The objective of this study was to phenotypically characterize lithic Salmonella phages from cattle, birds and swines, either from backyard or industrial systems, birds from periurban systems, zoo reptiles and Altiplanic animals. METHODOLOGY 675 animal samples were analyzed for this study. Phage isolation was performed using the overlay method with 0.7% TSA, with a pre-enrichment using 4 strains of Salmonella hosts (Infantis, Heidelberg, Typhimurium and Enteritidis). Only lithic phages were selected. These phages were purified, titrated by spot method and stored at refrigeration temperature. Subsequently, they were characterized in terms of their host range using 26 different serotypes of Salmonella (Moreno et al, 2013). Results A Table 1. Number of isolated phage and Salmonella by host Salmonella Animal system Analyzed samples Number of Salmonella strain Number of phage isolated for host Salmonella Heidelberg Salmonella Infantis Salmonella Typhimurium Salmonella Enteritidis Total Backyard birds 35 31 9 15 43 63 Intensive cattle (Valdivia) 160 3 4 28 45 Intensive pork 36 11 5 8 22 Wild birds periurban 49 30 1 32 44 Wild birds wetlands 271 21 27 Reptilians 6 18 Altiplanic animals 13 Cattle Easter Island 47 10 75 90 total 675 99 25 48 24 250 343 B Table 2. Serotypes of host Salmonella more susceptible by system Figure 1. Number of isolated phages for Salmonella host Animal system Average lisis Salmonella serotypes more susceptible Cattle Easter Island 6,2 JAVIANA,HEILDERBERG,DUBLIN Y ENTERITIDIS Intensive cattle (Valdivia) 4 JAVIANA, DUBLIN Y ENTERITIDIS Backyard birds 4,6 Wild birds wetlands 6,7 PANAMA,MBANDAKA,NWPORT,BARANDERUP Wild birds periurban 3,5 JAVIANA,HEILDERBERG,DUBLIN Y ENTERITIDIS, 4,5,12:i:- Intensive pork 4,2 Reptilian 2,03 Altiplanic animals C TP: Backyard birds IP: Cattle Easter Island AS: Wild birds wetlands Figure 2. A. Heatmap of isolated phage from Easter Island cattle and Valdivia intensive bovine production systems both negative to Salmonella isolation. B. Heatmap of isolated phage from intensive pork, South American camelids and zoo reptilian. C. Phage of backyard birds, wild wetlands, wild peri-urban .The vertical axis is the Salmonella cluster, the horizontal axis is the phage cluster. Red represents lysis and blue don`t represent lysis Figure 3. Fragment Length Polymorphism RFLP. It shows different cutting patterns using the enzymes EcoI, EcoV, HindIII. Different patterns were found per system and was found to be insensitive among some phages from different systems. Conclusions The dynamics between phages and Salmonella, conditions the behavior of phages. In all the systems found phages of wide host range, the most extensive was the wild bird of wetlands. The most susceptible strains Salmonella, present in all the systems studied, were Enteritidis, Javiana and Typhimurium. It is important to be able to understand the role of phage-Salmonella dynamics in the different animal systems, since these systems are a source of maintenance, amplification and diversification of Salmonella enterica, considering that phages are one of the main engines of bacterial change. REFERENCIAS Reyes, A., Semenkovich, N. P., Whiteson, K., Rohwer, F., & Gordon, J. I. (2012). Going viral: next-generation sequencing applied to phage populations in the human gut. Nature Reviews Microbiology, 10(9), 607-617. Moreno Switt, A.I., den Bakker H, C.,Vongkamjan, K., Warnick, L, D., Cumming, K, J., and Wiedmann, M., 2013. Salmonella bacteriophage diversity reflects host diversity on dairy farms. Food Microbiol. 36, 275-285. Wongsuntornpoj, S., Moreno Switt, A.I., Bergholz, P., Wiedmann, M., Chaturongakul, S., 2014. Salmonella phages isolated from dairy farms in Thailand show wider host range than a comparable set of phages isolated from U.S. dairy farms. Vet. Microbiol. 172, 345–52. doi:10.1016/j.vetmic.2014.05.023 AGRADECIMIENTOS: Proyectos FONDECYT 11140108, Proyecto Regular UNAB DI-1300-16/RG and Martin Wiedmann (Cornell U.)