- Volume 1, Issue 10, 2019

Introduction. Invasive infections due to Cellulosimicrobium spp. (a Gram-positive coryneform) are extremely rare. Only a few cases of bloodstream infections and endocarditis have been described, as bacteraemia due to coryneforms is usually discarded as blood culture contamination.

Case presentation. A 66-year-old female, with a history of aortic valve replacement, presented with fever, left leg purpura and acute kidney injury. Multiple repeated blood cultures were positive for Cellulosimicrobium cellulans , and targeted therapy was started. At first, endocarditis was excluded by echocardiograms, and the acute nephritis was interpreted as an atypical presentation of Henoch–Shönlein purpura. High-dose prednisone was started, and after 10 weeks the patient presented again with fever, mental confusion and acute left arm ischaemia. A subsequent echocardiogram and radiolabelled leukocyte scintigraphic evaluation revealed aortic prosthetic valve endocarditis with periprosthetic abscess and arterial brachial thrombosis. The patient deceased, and the autoptic examination confirmed an aortic valve periprosthetic abscess and revealed multiple arterial thromboses and septic embolisms in the kidneys, brain, spleen and myocardium.

Conclusion. Isolation of coryneform bacteria on blood culture should not always be discarded as blood culture contamination. In the case of endocarditis due to Cellulosimicrobium spp., the removal of any prosthetic material, along with prolonged in vitro active antimicrobial therapy, should be pursued in order to reduce persistence or relapses of infection.

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms found in soil and water. Infections caused by NTM are increasing with conditions ranging from harmless colonization to invasive infections, the latter being more common in immunocompromised hosts. In this report, we present a case of bacteraemia caused by Mycobacterium chelonae , a rapidly growing NTM belonging to Class IV in the Runyon classification, in a 71-year-old male with ocular myasthenia gravis undergoing treatment with oral prednisolone. Gram staining of these organisms from blood culture can be easily overlooked or confused with diptheroids. Detection of Gram-positive bacilli should prompt Ziehl–Neelsen staining to distinguish diphtheroids from rapidly growing mycobacteria in immunosuppressed patients. In addition, speciation and antimicrobial susceptibility testing are of paramount importance in such cases as there is considerable variation in the resistance patterns between different species of NTM. Line probe assay provides a rapid and reliable method for identification of NTM to the species level, which can guide treatment with appropriate antibiotics. This case report highlights the importance of early detection of such cases so as to optimize management and improve patient outcomes.