Despite winning FDA approval on Monday to market the antibiotic Zemdri (plazomicin) to treat adults with complicated urinary tract infections (cUTI) or pyelonephritis, Achaogen Inc. saw shares (NASDAQ:AKAO) sink 20.2 percent to $9.59 on Tuesday as the agency rebuffed its effort to secure approval to use the treatment of bloodstream infections (BSIs) with a complete response letter (CRL).