Susceptibility of Clostridium difficile isolates of varying antimicrobial resistance phenotypes to SMT19969 and 11 comparators.

We determined the in vitro activity of SMT19969 and 11 comparators, including metronidazole, vancomycin and fidaxomicin, against 107 C. difficile isolates of different antimicrobial resistance phenotypes. Fidaxomicin and SMT19969 were most active. Geometric mean fidaxomicin and SMT19969 MICs were highest in ribotypes known to show multiple resistance. Co-resistance to linezolid and moxifloxacin was evident in ribotypes 001, 017, 027 and 356. High-level ceftriaxone resistance in ribotypes 356 and 018 was location-linked