Achaogen, a South San Francisco developer of antibacterial compounds, said it has raised $26M in a second round of financing, led by new investor Domain Venture Partners.

All of Achaogen’s first-round investors (5AM Ventures, ARCH Venture Partners, Venrock Associates, and Versant Ventures) participated in the round, it said. The company said it will use the money to advance its lead antibacterial program through clinical proof of concept, and to progress additional programs through preclinical development.

The company focuses on small molecules that inhibit the emergence of bacterial resistance.

It raised $15 million in 2004.