In Vitro Activity of Rifampin, Rifabutin, Rifapentine, and Rifaximin against Planktonic and Biofilm States of Staphylococci Isolated from Periprosthetic Joint Infection
- Antimicrob Agents Chemother. 2019 Oct 22;63(11):e00959-19. doi: 10.1128/AAC.00959-19.
- 1. Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
- 2. Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
- 3. Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
- 4. Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA [email protected].
The in vitro activities of rifampin, rifabutin, rifapentine, and rifaximin were tested against 200 periprosthetic joint Infection (PJI)-associated staphylococci. Seven rifampin-resistant isolates had MICs of ≥4 μg/ml. Three isolates had rifampin MICs of 0.25 to 1 μg/ml and harbored an Asp471Gly RpoB variant, suggesting that the CLSI rifampin-susceptible staphylococcal breakpoint of ≤1 μg/ml may be too high. The remaining isolates had rifampin MICs of ≤0.016 μg/ml, and the rifampin, rifabutin, rifapentine, and rifaximin minimum biofilm bactericidal concentrations (MBBC) for ≥50% of isolates were 8, 1, 2, and 4 μg/ml (for S. aureus) and 2, 0.06, 0.25, and 0.5 μg/ml (for S. epidermidis), respectively, for rifampin-susceptible isolates. Nonrifampin rifamycins have promising staphylococcal activity, including antibiofilm activity.