Isolation of Bacteriophage against Salmonella typhi and its Potential to Control Biofilm

Abstract

Bacteriophages are known to be the most abundant entity in the universe. They infect bacteria and replicate inside bacterial cells either by lytic or lysogenic cycle. Bacteriophages have been employed for many applications i.e. for transfer of gene/protein vaccines, an alternative to antibiotics, screening of peptides/proteins, identification of pathogens etc. They also have an important role in controlling biofilm, an aggregation of microbial cells that are adhered to inert/biological surface or with each other. Biofilms are resistant to antibiotics and other disinfectants so they a play major role in the spread of disease, so an alternative should be find out to control biofilm formation. Amongst biofilm forming bacteria, Salmonella typhi is gram negative, rod shaped bacterium that is involved in spread of typhoid fever. Due to poor administrative measures of antibiotics, this bacterium has developed resistant towards 3rd generation antibiotics. This study aimed to isolate bacteriophage against Salmonella typhi and to control biofilm formation. Bacteriophages were isolated from sewage water against clinical bacterial strains and characterization of isolated phage showed it to be stable at long temperature range (37-65 ºC) and pH range (5-11) with adsorption rate increased by presence of divalent metal ions. The burst size of bacteriophage is 300 virions per cell with 24 minutes latent time period. The isolated phage reduced bacterial population to 2 folds in planktonic culture and 2.2 folds in the biofilm. In conclusion our findings suggest that waste water is a good source for finding bacteriophages against newly emerging antibiotic resistant bacteria Salmonella typhi. Phages can be used to control bacteria both in planktonic forms, as well as in biofilms. In conclusion our findings suggest that waste water is a good source for finding bacteriophages against newly emerging antibiotic resistant bacteria Salmonella typhi. Phages can be used to control bacteria both in planktonic forms, as well as in biofilms