Abstract
Aim
To assess the clinical characteristics, diagnostic tests and treatment strategies in orthopedic implant-associated infections (OIAI) caused by Cutibacterium spp.
Method
We retrospectively included consecutive patients with OIAI caused by Cutibacterium spp. treated at our institution from January 2012 to January 2017. OIAI was diagnosed when: (i) macroscopic purulence, sinus tract or exposed implant was present; (ii) acute inflammation in peri-implant-tissue was documented; (iii) Cutibacterium spp. grew in joint aspirate, ≥2 intraoperative peri-implant tissue samples or in sonication fluid of the removed implant (>50 CFU/ml).
Results
Of 67 patients with Cutibacterium OIAI, 42 (63%) had an infected joint prosthesis (21 hip, 12 shoulder, 9 knee) and 25 (37%) an infected fixation device (10 spinal hardware, 11 osteosynthesis, 2 anchorages after rotator cuff reparation, 2 cruciate ligament grafts). 53 (84%) presented with a delayed (3–24 months) or late (>24months) infection. 62 infections were caused by C. acnes and 5 by C. avidum, all being susceptible to levofloxacin and rifampin. Among non-culture-based diagnostic tests, tissue histology had the highest sensitivity (68%), followed by increased synovial fluid leukocyte count/differential (59%). Of culture-based tests, sonication fluid culture showed the highest sensitivity (83%), followed by tissue culture (71%) and synovial fluid culture (61%). Culture positivity rates of synovial fluid, peri-implant tissue and sonication fluid were 20%, 41% and 40%, respectively, after 7 days of incubation and 58%, 74% and 78%, respectively, after 14 days. Most patients were treated with one-stage (24%) or two-stage (55%) implant exchange of the implant. The majority of patients received oral levofloxacin and rifampin for 6–12 weeks.
Conclusions
Cutibacterium spp. affected various types of orthopaedic implants in different anatomic locations (lower and upper limbs and spine). Conventional diagnostic tests showed limited sensitivity of Cutibacterium OIAI and can be easily missed when cultures are incubated less than 10–14 days. All Cutibacterium isolates were susceptible to levofloxacin and rifampin.
