IMPACT OF GLYCEROL AND DIMETHYL SULFOXIDE ON THE PERSISTENCE OF PASTEURELLA MULTOCIDA DURING ITS PRESEVATION AT DIFFERENT TEMPERATURES

Bacterium Pasteurella multocida type B:2 is the causative agent of Hemorrhagic Septicemia in bovines in Pakistan. This organism is also being used for oil adjuvanted (Montanide ISA 50 V2) vaccine for mass vaccination in cattle & buffaloes in Punjab, Pakistan. A study was conducted to study the impact of glycerol and dimethyl sulfoxide (DMSO) on persistence of P. multocida duringits course of storage at 0, 4 and – 20 °C. Pure seed of P .multocida was grown in Brain Heart Infusion(BHI) broth at pH 7.4 and incubated at 37 °C for 18 hrs. in shaking incubator. The growth was observed for its purity microscopically as well as culturing on MacConkey’s & Nutrient agar slants.  The pure culture was divided into three parts. One part was added with 5 % sterilized DMSO (final concentration) and second part was added with 10 % sterilized DMSO (final concentration) and 15 %  glycerine (final concentration) while third part was kept as control without addition of DMSO and glycerine. All three parts were aliquoted (1 mL) in sterilized 1.5 mL eppendroff tubes and stored at three different temperatures i.e 0, 4 and – 20 °C. Eppendroff tubes from different temperatures were thawed in water bath (22 °C) and subjected to direct culturing on BHI broth, microscopic examination, purity testing on slants, culture turbidity / Optical Density (OD) values, dry biomass calculation and mice inoculation test for three months with 15 days intervals. The results indicated that pure P. multocida culture mixed with 10 % sterilized DMSO and 15 % sterilized glycerol stored at – 20 °C survived for three months and can be used for HS vaccine production without losing its survival.