Ceftriaxone treatment of spondylodiscitis and other serious infections with Cutibacterium acnes.

Objectives: To establish testing and treatment recommendations for a ceftriaxone once-daily dose regimen for systemic infections with Cutibacterium acnes. Methods: A review of the literature and a retrospective evaluation of patients diagnosed with C. acnes spondylodiscitis and treated with ceftriaxone were performed. Ceftriaxone and penicillin MICs were determined for C. acnes isolates from blood and biopsies and the epidemiological cut-off (ECOFF) was determined with surveillance data from the UK Anaerobe Reference Laboratory in Cardiff. Results: Limited clinical data exist from endocarditis and prosthetic joint infections using treatment with ceftriaxone 2g once daily for C. acnes with ceftriaxone MICs <= 0.5mg/L. In this case study, five patients were successfully treated with ceftriaxone as part of the treatment for spondylodiscitis with C. acnes. Ceftriaxone and penicillin MICs of the C. acnes isolates from the patients were 0.016-0.125mg/L and 0.012-0.032mg/L, respectively. The ceftriaxone ECOFF was 0.5mg/L and the penicillin ECOFF was 0.25mg/L based on available surveillance data. Conclusions: From the data presented in this study it would be acceptable to consider treatment with a once-daily dose of ceftriaxone 2g for systemic infections, including endocarditis, spondylodiscitis and prosthetic joint infections with C. acnes using a clinical breakpoint of <= 0.5mg/L (the ECOFF). However, clinical data are still limited and the response of patients treated with ceftriaxone for serious infections with C. acnes should be monitored closely.