Solithromycin is a highly potent next-generation macrolide, the first fluoroketolide, which has potent activity against most macrolide-resistant strains. In vitro and in vivo studies have shown potent activity against S. pneumoniae as well as an extended spectrum of activity against CA-MRSA, enterococci, Mycobacterium avium and in animal models of malaria. It is also active against atypical bacteria, such as Legionella, Chlamydophila, Chlamydia, Mycoplasmaand Ureaplasma and against gonococci and other organisms that cause genitourinary tract infections. It is 8-16 times more potent than azithromycin and is active against azithromycin-resistant strains. Its activity against resistant strains is driven by its ability to bind to three sites on the bacterial ribosome, compared to one or two for current macrolides. It binds to the large 50S subunit of the ribosome and inhibits protein biosynthesis. The binding to three ribosomal sites is expected to limit resistance development. On July 2016 Cempra Announces FDA Acceptance of IV and oral formulations of Solithera (solithromycin) New Drug Applications for in the treatment of community-acquired bacterial pneumonia.