SAN DIEGO, Sept. 14 /PRNewswire-FirstCall/ -- Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR) today announced the presentation of results from its second prulifloxacin Phase 3 clinical study for the treatment of infectious diarrhea in travelers, by clinical investigator Robert Steffen, M.D., at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in San Francisco.