Abstract
Corynebacterium spp. are rarely considered as pathogens but data in orthopedic infections are sparse. Therefore, we asked how often Corynebacterium spp. caused an infection in a defined cohort of orthopedic patients with a positive culture. In addition, we aimed to determine the species variety and susceptibility of isolated strains in regards to potential treatment strategies. Between 2006 and 2015, we retrospectively assessed all Corynebacterium sp. bone and joint cultures from an orthopedic ward. The isolates were considered as relevant indicating an infection if the same Corynebacterium sp. was present in at least two samples. We found 97 orthopedic cases with isolation of Corynebacterium spp. (128 positive samples), mainly Corynebacterium tuberculostearicum (n=26), Corynebacterium amycolatum (n=17), Corynebacterium striatum (n=13), and Corynebacterium afermentans (n=11). Compared to a cohort of positive blood cultures, we found significantly more C. striatum and C. tuberculostearicum but no C. jeikeium cases. Only 16 cases out 66 cases (24.2%) with an available diagnostic set of at least 2 samples had an infection. Antibiotic susceptibility testing (AST) of different antibiotics showed various susceptibility results except for vancomycin and linezolid with a 100% susceptibility rate. Rates of susceptibility of corynebacteria isolated from orthopedic samples and of isolates from blood cultures were comparable. In conclusion, our study results confirmed that Corynebacterium sp. is most often isolated as a contaminant in a cohort of orthopedic patients. AST is necessary to define the optimal treatment in orthopedic infections.
Kalt, Fabian