Dynamic PET-facilitated modeling and high-dose rifampin regimens for Staphylococcus aureus orthopedic implant-associated infections

Sci Transl Med. 2021 Dec;13(622):eabl6851. doi: 10.1126/scitranslmed.abl6851. Epub 2021 Dec 1.

Abstract

Staphylococcus aureus is a major human pathogen causing serious implant–associated infections. Combination treatment with rifampin (10 to 15 mg/kg per day), which has dose-dependent activity, is recommended to treat S. aureus orthopedic implant–associated infections. Rifampin, however, has limited bone penetration. Here, dynamic 11C-rifampin positron emission tomography (PET) performed in prospectively enrolled patients with confirmed S. aureus bone infection (n = 3) or without orthopedic infection (n = 12) demonstrated bone/plasma area under the concentration-time curve ratio of 0.14 (interquartile range, 0.09 to 0.19), exposures lower than previously thought. PET-based pharmacokinetic modeling predicted rifampin concentration-time profiles in bone and facilitated studies in a mouse model of S. aureus orthopedic implant infection. Administration of high-dose rifampin (human equipotent to 35 mg/kg per day) substantially increased bone concentrations (2 mg/liter versus <0.2 mg/liter with standard dosing) in mice and achieved higher bacterial killing and biofilm disruption. Treatment for 4 weeks with high-dose rifampin and vancomycin was noninferior to the recommended 6-week treatment of standard-dose rifampin with vancomycin in mice (risk difference, −6.7% favoring high-dose rifampin regimen). High-dose rifampin treatment ameliorated antimicrobial resistance (0% versus 38%; P = 0.04) and mitigated adverse bone remodeling (P < 0.01). Last, whole-genome sequencing demonstrated that administration of high-dose rifampin in mice reduced selection of bacterial mutations conferring rifampin resistance (rpoB) and mutations in genes potentially linked to persistence. These data suggest that administration of high-dose rifampin is necessary to achieve optimal bone concentrations, which could shorten and improve treatments for S. aureus orthopedic implant infections.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use
  • Humans
  • Mice
  • Microbial Sensitivity Tests
  • Positron-Emission Tomography
  • Rifampin* / pharmacokinetics
  • Rifampin* / therapeutic use
  • Staphylococcal Infections* / drug therapy
  • Staphylococcal Infections* / microbiology
  • Staphylococcus aureus

Substances

  • Anti-Bacterial Agents
  • Rifampin