A Study recently published in the journal The Lancet Infectious Diseases indicates that overuse of fluoroquinolones may be sole cause of deadly C. Diff Epidemic. Antibiotic overuse can have severe consequences, especially with certain types of antibiotics and this study begins to quantify one of the ways in which this happens and how widespread the harm can be.

Some background published last year on  C Diff epidemic, including the role that antibiotics play in causing it:

NBC-News: Baddest Bug: C. Diff Hits Half a Million Americans

Articles discussing the recent new study indicating that fluoroquinolones are the class of antibiotics primarily responsible:

Consumer Reports- Surprising Remedy for Deadly Hospital Infections

Medical Express- Antibiotics, not dirty hospitals, the main cause of C. difficile epidemic