TORONTO, - Optimer Pharmaceuticals Canada, Inc. announced today the approval of DIFICID (fidaxomicin) by Health Canada for the treatment of Clostridium difficile infection (CDI) in patients 18 years of age and older. DIFICID was approved in Canada on a priority basis recognizing the critical need for new options to treat this disease and is the first new treatment for CDI in over 20 years.