Mycobacterium chelonae bacteraemia in a patient with myasthenia gravis receiving long-term steroid therapy

Abstract

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.

Nontuberculous mycobacterial infections in patients with hematologic malignancies and recipients of hematopoietic stem cell transplantation

“…The diagnosis of NTM associated CRI is primarily established through positive blood, catheter material and/or wound swab cultures at the CVC exit site. Detection of initial and nonspeciated Gram-positive bacilli from these sites in immunocompromised patients should also raise the suspicion for RGM CRI 47,48. Identifying M. mucogenicum or any other RGM from blood cultures should always be considered significant, and CRI should TA B L E 1 Clinical syndromes, susceptibility testing, and treatment recommendations for select mycobacterial species in patients with hematologic malignancies and HSCT recipients.…”