Rib-X Pharmaceuticals (New Haven, CT) a clinical-stage small molecule drug discovery company developing antiinfectives against community acquired pneumonia, chronic bronchitis and complicated skin infections, closed a $20M Series E financing. Participants have included Warburg Pincus, ABS Ventures, Axiom Ventures, EuclidSR Partners, MedImmune Ventures, Oxford Bioscience Partners, SR One and Vox Equity Partners.