Stability and infectivity of bacteriophages under different environmental conditions

Abstract

Now a days, 80 % of the water resources have been polluted with various kinds of wastes, viz., domestic, industrial and agricultural wastes that includes salts, sugars, detergents, metals, agrochemicals especially pesticides etc. These pollutants may have an adverse impact on the microbial communities in the water bodies. Viruese of bacteria i.e. bacteriophages play a crucial role in maintaining ecological balance of the ecosystem. Pollutants present in the water may have direct effect on the stability and infectivity properties of such viruses present in the water environment. The main objective of the present work was to study the effect of chemical pollutants on stability and infectivity on phage particles in the natural environmental conditions. Stability of lytic9able to destroy its host bacterium) phages of Salmonella Paratyphi B, Pseudomonas aeruginosa and Klebsiella pneumoniae (viz., φSPB, BVPaP-3 and KPP respectively) was studied by exposing respective phage particle to various chemical factors for 1h and then determining remaining active phage particles by double agar layer plaque assay technique. Infectivity of φSPB, BVPaP-3 and KPP was studied at the sub-inhibitory concentration (SIC) values of chemical pollutants for the respective bacterial pathogen The infectivity of phage was determined in terms of number of plaque forming units after 24 h at 37 ËšC. They are found sensitive to SDS and Cetrimide but resistant to Tween 80 with 100% stability. Phages are found resistant to pesticide like Mancozeb but sensitive to Malathion. Zn2+, Co2+, Cd2+ exhibited stimulatory effect on stability of these phages. Phages viz., φSPB, BVPaP-3 and KPP could not able to infect their hosts in the presence of SDS and Cetrimide but in presence of Tween 80 infectivity was 100%. At lower concentrations of metals (Zn2+, Co2+, Cd2+), infectivity was almost 100 %. However, this particular study could be helpful in the use of φSPB, BVPaP-3 and KPP phages as biocontrol agent in water bodies against life threatening pathogens in the future