<prompt> The most common organism causing acute tonsillitis is:Staph aureusAnaerobesHemolytic streptococciPneumococcus  <response>: Group A beta hemolytic streptococci is the MC bacteria causing acute tonsillitis. other causes are: staph aureus pnuemococci H. Influenza Ref Dhingra 5e,p 341,6e,p 288. 