Cutibacterium (Formerly Propionibacterium) avidum: A Rare but Avid Agent of Prosthetic Hip Infection.

BACKGROUND: Cutibacterium spp. (formerly Propionibacterium) are slow-growing cutaneous anaerobic commensals, rarely reported in prosthetic joint infections (PJIs). We describe epidemiological, clinical, biological, and radiological characteristics of 15 Cutibacterium avidum PJIs, their treatments, and outcomes.

METHODS: This study is an observational, monocenter study (January 2004 to April 2017), with comparison of C avidum vs Cutibacterium acnes (n = 40) PJI characteristics.

RESULTS: Among 1179 PJIs treated during the study period, 15 (1%) PJIs were due to C avidum (14 classified as late chronic and 1 as early postoperative). They involved only obese patients with hip arthroplasties (median age 65 years, body mass index 35 kg/m2 ). Twelve patients' PJIs developed after primary hip arthroplasty. Thirteen patients' last clean operation had used an anterior approach. Fourteen preoperative joint aspirate cultures yielded C avidum. The 14 chronic PJIs were treated with 1-stage exchange arthroplasty, the acute case with excision synovectomy. Antibiotic therapy was administered for 12 [6-13] weeks, intravenously for 4 [2-6] weeks. The most used first-line agents were intravenous clindamycin (n = 8) or cefazolin (n = 6). After median follow-up of 27 [3-136] months, 1 relapse occurred. Compared to C acnes PJI patients, those with C avidum PJIs were significantly younger, had higher body mass indices, had only hip involvement, and had more frequent anterior surgical approach. C acnes PJIs were more frequent after revision arthroplasty.

CONCLUSION: C avidum is a rare PJI agent occurring in a particular subpopulation. Joint aspiration is the key diagnostic tool. Our results suggest that PJI risk factors include obesity, primary hip arthroplasty, and anterior surgical approach. Efforts to prevent these infections in high-risk patients should be developed.