The stock culture, stored at −20 °C was transferred in TSA agar plates (Tryptone soya agar, OXOID, Cambridge, UK). After 18 h of incubation at 37 °C, one colony was picked and inoculated into a 15 mL sterile tube containing 3 mL of TSB (Tryptic Soy Broth, Difco Laboratories, Detroit, MI) and was incubated at 37 °C overnight.