Is Corynebacterium striatum an emerging prosthetic joint infection pathogen and how should it be treated?

Introduction: The aim of this study was to assess the incidence of Corynebacterium striatum prosthetic joint infections (PJI) to determine if an increase has occurred recently. Moreover, susceptibility testing was conducted on C. striatum preserved isolates to determine antibiotic options for these infections.

Methods: Retrospective review of PJI cases was conducted from 1/2017 through 1/2021 compared to 1/2021 through 7/2022 to determine how many cases of C. striatum have occurred for each of these time points. From these cases, demographics, outcomes and risk factors for C. striatum PJI were recorded. The preserved clinical isolates from these cases were tested for susceptibility to different antibiotics.

Results: A statistically significant increase in the proportion of C. striatum PJI cases (1.98 to 7.84, p=0.0489) has occurred over the past 16 months at a single institution. Chronic wounds and exposure to daptomycin were associated with the majority of these cases. Susceptibility testing of the clinical isolates showed uniform susceptibility to vancomycin, linezolid and dalbavancin. Uniform resistance was seen with ciprofloxacin, tetracycline and doxycycline as well. Interestingly, 85.7% of the isolates displayed inducible daptomycin resistance after overnight exposure to daptomycin.

Conclusions: C. striatum is an emerging PJI pathogen. It is important for clinicians to be cognizant that this pathogen can have inducible high level daptomycin resistance and that daptomycin is likely not a reliable antibiotic for these infections. While vancomycin and linezolid are the traditional antibiotics to use in these infections, other antibiotics such as dalbavancin, may also have utility, but more research is needed to determine the effectiveness of this antibiotic in C. striatum infections.