Factors associated with rifampin resistance in staphylococcal periprosthetic joint infections (PJI): a matched case-control study.

PURPOSE: Rifampin combination therapy plays an important role in the management of staphylococcal periprosthetic joint infection (PJI). However, the emergence of rifampin resistance is a feared complication. We retrospectively analysed predetermined potential risk factors in patients with rifampin-resistant staphylococcal PJI in a multicentre case-control study.
METHODS: Cases (n = 48) were defined as PJI caused by rifampin-resistant staphylococci. Rifampin-susceptible controls (n = 48) were matched for microorganism and type of prosthetic joint. Uni- and multivariable conditional logistic regression analyses were performed to estimate odds ratios (OR) with 95 % confidence intervals (95 % CI).
RESULTS: Forty-eight cases (31 men; median age 67 years; age range 39-88 years) with hip- (n = 29), knee- (n = 13), elbow- (n = 4), shoulder- (n = 1) or ankle-PJI (n = 1) were enrolled in the study. Staphylococcus aureus and coagulase-negative staphylococci were isolated in ten and 38 episodes, respectively. Most of the cases (n = 44, 92 %) had a previous PJI, and 93 % (n = 41) of these had been treated with rifampin. There was an independent association of emergence of rifampin resistance with male sex (OR 3.6, 95 % CI 1.2-11), ≥ 3 previous surgical revisions (OR 4.7, 95 % CI 1.6-14.2), PJI treatment with high initial bacterial load (inadequate surgical debridement, <2 weeks of intravenous treatment of the combination medication; OR 4.9, 95 % CI 1.6-15) and inadequate rifampin therapy (OR 5.4, 95 % CI 1.2-25).
CONCLUSIONS: Based on our results, extensive surgical debridement and adequate antibiotic therapy are needed to prevent the emergence of rifampin resistance.