<prompt> Streptococcus pyogenes can be checked by which drug diskBacitracinPolymycinOptochinNone of the above  <response>: Ans. a BacitracinRef.: Microbiology by Ananthanarayan and Paniker 8th ed. 201, 206-07, 2012 The various species of Streptococcus can be checked by various drug disks which is indicated as whether it is sensitive or resistant to the drug. S. pyogenes is bacitracin sensitive. S. agalactiae is bacitracin resistant. S. pneumoniae is inhibited by optochin. S. viridans is not inhibited by optochin. 