Microbiological studies and evaluation of the antiviral activity of some bacterial extracts

Abstract

The control of viral-induced infectious diseases is important as a scientific goal in last years. Bovine Viral Diarrhea Virus (BVDV) was used to evaluate the antiviral activity of 13 bacterial isolates usingMadin Darby Bovine Kidney cells (MDBK) as cell culture system. Eight isolates were able to inhibit the activity of BVDV. Among them, 5 isolates showed 100% activity against BVDV were identified as Bacillus cereus strainLJ01,Bacillus cereus strain FT9, Pseudomonasputida strain sda2,Bacillus thuringiensis Bt407,Xanthomasfuscansbased on 16S rRNAgene analysis. Different physical and chemical conditions were used to obtain the maximum protein and carbohydrates contents ofPseudomonas oleovorans.The best conditions were 24 hours culture age, temperature 30°C at 200 rpm, initial pH 7.5and inoculum size 1.5 ml/100ml. In addition optimum 0.4% casamino acids and 0.78% NaClof Casamino acids Yeast extract Glucose (CYG) production medium. Cell free Culture ofPseudomonas oleovoranswas extracted by ethyl acetate followed by different concentrations of chloroform: methanol. The activity of the extracted fraction no.4 showed 80% inhibition of BVDV using plaque reduction assay. GC/Mass analysis of this fraction identified the presence of two saturated fatty acid esters called tetradecanoic acid and hexadecanoic acid methyl esters.