Cutibacterium Positive Cultures in Total Hip Arthroplasty: Contaminant or Pathogen?

ABSTRACT

BACKGROUND: Cutibacterium spp. is an emerging pathogen in total hip arthroplasty (THA) that is not well evaluated in the literature. This study reported on the presentation and management of THA complicated by positive intraoperative Cutibacterium cultures. METHODS: This is a retrospective review of 27 revision THAs with positive monomicrobial intraoperative Cutibacterium cultures from 2014 to 2020 at one academic center. These patients were divided into two cohorts based on meeting Musculoskeletal Infection Society (MSIS) criteria for prosthetic joint infections (PJI). Patient demographics, preoperative labs, and hip aspirate results were collected. Procedure performed, postoperative antibiotic regimens, and repeat infections were recorded. Data were compared with univariate analysis. RESULTS: Nine of the 27 patients preoperatively met MSIS criteria for PJI. Patients with positive MSIS criteria had significantly higher median synovial cell count (P = .048) and neutrophil percentage in a preoperative aspirate (P = .050). Eight patients with positive MSIS criteria received six weeks of postoperative antibiotics compared to two patients with negative criteria. Two patients with positive MSIS criteria had a postoperative infection that required further surgical intervention. Four patients with negative criteria who required further surgical intervention did not receive postoperative antibiotics after initial revision. CONCLUSION: While often categorized as a contaminant, Cutibacterium is an increasingly recognized pathogen in THA. Cutibacterium can often present with normal serology, which may result in misdiagnosis as aseptic THA failure. Without the administration of postoperative antibiotics after positive cultures, there is a risk for persistent infection requiring further surgical intervention.