免疫能が正常な患者におけるMicrococcus luteus誘発性人工弁感染性心内膜炎：インドからの症例報告

Micrococcus luteus (M. luteus) is a Gram-positive microorganism that typically dwells in environments such as soil, water, and human skin, hence, entitling it as a contaminant organism. However, there are instances where M. luteus affects immunocompromised patients, such as in infective endocarditis and septic arthritis, but typically among immunocompromised patients. However, an evolutionary change has been observed in the infectious capability of this organism especially with reports emerging on its instance among immunocompetent population. A 68-year-old female presented to the emergency medicine department with complaints of persistent fever and neck soreness. Patient's blood culture reports were positive for M. luteus and owing to her history of undergoing prosthetic valve replacement. A preliminary diagnosis of prosthetic valve infective endocarditis was made. However, since M. luteus was a typical skin contaminant, and its infective etiology was limited toward immunocompromised patients, blood cultures were repeated for confirmation. Repeat blood cultures ascertained the suspicion of M. luteus; hence, treatment with intravenous vancomycin was initiated. Patient was discharged after 8 week of treatment following complete eradication of infective markers and symptomatic improvement. Here, we report the novel occurrence of prosthetic valve infective endocarditis, by a typically contaminant organism, in an immunocompetent individual, hence, raising concerns on the evolutionary changes in the organism, M. luteus.