Over the last decades, the overuse of antibiotics in treatment and prevention of fish farming diseases, leads the emergence of antibiotic resistant bacterial reservoirs, both in animals and aquatic environment, with consequent threat for human health as well as the environment. Within this context, the imperious need to introduce new sustainable techniques to ensure the treatment of these deseases in a harmless manner is completely necessary. Among these techniques, the use of bacterial strains producing bacteriocins might be considered as a affable alternative, not only for its inhibitory effect, also for the
beneficial effects in the host. This study is aimed to characterize bacterial strains with bacteriocin producing activity. To assess their bacteriocin producin activity 198 strains were isolated from
gastrointestinal tract of 198 different Cantabrian Sea wild fish species. TSA culture was used in order to isolate the strains according to its color morphology and shine. Among a total of 15 strains were found to produce bacteriocins against the aquaculture pathogenic generous Vibrio, Photobacterium and Shewanella, reflecting that the highiest antagonistic effect was shown by 4 strains. The bacterial strains were identified as Alcaligenes faecalis and Myroides marinus on the basis of PCR amplification of 16S ribosomal RNA gene followed by sequencing (>97% of homology). Finally the antibacterial activity was performed by three different treatments: thermostability, enzymes effect and pH effect
