179. Two Cases of Corynebacterium Striatum Prosthetic Valve Endocarditis Resulting in Opposing Outcomes

Background The Corynebacterium species is associated with bacteremia, cellulitis, and rarely, endocarditis. Corynebacterium endocarditis used to be an extremely rare disease; however, the development of mechanical devices boosted its prevalence, rendering it unignorable. This bacteria is also described as an emerging multi-drug-resistant pathogen. Methods We encountered two cases of Corynebacterium striatum prosthetic valve endocarditis, one of which was successfully treated. We failed to treat the other case despite prolonged medical treatment. We describe their clinical courses and literature review. Results (Case 1) A 74-old man was admitted to our hospital because of C. striatum prosthetic valve endocarditis. He relapsed twice despite treatment with adequate dosage and duration (6 weeks) of vancomycin during the first episode, and following daptomycin during the second episode depending upon the result of drug susceptibility. However, both medical treatments failed. He had refused surgery upon each hospitalization. He was treated with intravenous vancomycin and oral rifampin for 24 weeks. His endocarditis did not relapse after 6 months’ treatment. (Case 2) A 71-year-old man who had a past medical history of enterococcal endocarditis was successfully treated with intravenous ampicillin and subsequent atrial valve replacement. He was admitted to our hospital because of fever and back pain. Prosthetic valve endocarditis was diagnosed because blood cultures revealed C. striatum, and evidence of metastatic lesions. While intravenous vancomycin and oral rifampin (600 mg/day) were initiated, several complications, such as pseudoaneurysm of ascending aorta, splenic artery aneurysm followed by a rupture, and cerebral hemorrhage occurred. The patient’s refusal of a re-operation rendered prolonged medical treatment necessary for 16 weeks. He died 20 weeks after the diagnosis of Corynebacterium endocarditis. Conclusion The same antibiotic treatment regimen resulted in opposing outcomes in our two patients. To the best of our knowledge, only 22 cases were previously described in English literature. However, there was no well-established medical treatment against this pathogen. Our experience might be beneficial for similar patients worldwide. Disclosures All authors: No reported disclosures.