Determination of Adsorption Capacity of Alum Hydroxide {Al (OH) 3} Gel for Streptococcus equi sub specie equi and Streptococcus dysgalacltae sub species equisimillis

The present study was conducted to determine the adsorption capacity of Alum Hydroxide gel for Streptococcus equi and Streptococcus equisimillis in combination. One ml of streptococcal inoculum containing live count of Streptococcus equi @ 2 × 109/ml and Streptococcus equisimillis @ 2 × 109/ml inoculated in each of six Eppendorf tubes containing 0.2 mg, 0.4 mg, 0.6 mg, 0.8 mg, 1.0 mg and 2.0 mgs of autoclaved Aluminium Hydroxide in the form of gel, mixed and centrifuged at 1600 rpm for 15 minutes produced supernatant, which upon streaking and incubation on seven nutrient agar plates including supernatant from 7th control negative Eppendorf tube containing sterilized normal saline produced different number of colonies after adsorbing streptococcal cells depending upon the concentration of Al(OH)3 in gel. 50 colonies were counted from supernatant recovered from Eppendorf containing 0.2 mg of Aluminium Hydroxide, 25 colonies from supernatant over 0.4 mg, 15 colonies from supernatant over 0.6 mg, 10 colonies from supernatant over 0.8 mg and no colony was obtained from supernatants over 1.0 mg and 2.0 mgs of Aluminium Hydroxide while 100 colonies were recovered from control negative ependorf containing only normal saline without Aluminium Hydroxide. It is concluded that Aluminium Hydroxide as gel should be used as adjuvant @ 1 mg per ml of streptococcal inoculum in a streptococcal vaccine.