The invention relates to novel forms of compounds displaying broad spectrum antibiotic activity, especially crystalline polymorphic forms and amorphous forms of such compounds, compositions comprising such crystalline polymorphic forms and amorphous forms of such compounds, processes for manufacture and use thereof. The compounds and compositions of the invention are useful in the pharmaceutical industry, for example, in the treatment or prevention of diseases or disorders associated with the use of antibiotics, chemotherapies, or antiviral therapies, including, but not limited to, colitis, for example, pseudo-membranous colitis; antibiotic associated diarrhea; and infections due to Clostridium difficile ("C. difficile"), Clostridium perfringens ("C. perfringens"), Staphylococcus species, for example, methicillin-resistant Staphylococcus, or Enterococcus including Vancomycin-resistant enterococci.