A Case of Cutaneous Mycobacterium Chelonae Abscessus Infection in a Renal Transplant Patient

Abstract

Background: Mycobacterium chelonae is an atypical “fast-growing Mycobacteria” that is a rare cause of human infection. There have been several reports of cutaneous infection among immunosuppressed patients, as well as in immunocompetent individuals following trauma. Most cases to date seem to have occurred among renal transplant recipients, raising the possibility that there is something inherent to the renal transplant patient that increases their susceptibility more than other immunocompromised patients. Objective: The differential diagnosis of subcutaneous nodules distributed in a sporotri-choid pattern is extensive, particularly in an immunocompromised host. Although several cases of cutaneous M. chelonae abscessus infection have been reported among both immunosuppressed and immunocompetent patients, the clinical presentation has varied, and few cases have reported the appearance of lesions in a sporotrichoid pattern. We present a case of a renal transplant patient with a reported history of trauma to the lower extremities, who presents with subcutaneous nodules distributed in a sporotrichoid pattern. The patient is found to have M. chelonae abscessus infection, fails several treatment regimens, and presents with a recurrence. The literature of M. chelonae infection is reviewed, and the various treatment options are discussed. Methods: An initial skin biopsy was stained with Hematoxylin and Eosin and revealed deep dermal abscesses with acid-fast bacilli in clusters. The culture became positive for Mycobacterium chelonae abscesses in four days and was found to be sensitive to multiple antibiotics. The patient underwent surgical excision of 14 nodules, which revealed findings consistent with the skin biopsy, and was subsequently treated with the appropriate antibiotics. Results: Despite treatment with a full course of an organism-sensitive antibiotic regimen, the patient returned with persistent and recurrent nodules six weeks later. The patient was then treated as an inpatient with a seven-week course of intravenous antibiotics and was discharged home on a combined intravenous and oral regimen. Conclusion: Although M. chelonae abscessus is an extremely rare cause of infection among humans, there seems to be a predominance of cases reported among renal transplant patients. The explanation for this is not entirely clear; however, the organism must be considered as a cause of infection in any renal transplant recipient who presents with subcutaneous nodules. Eradication of the organism presents a tremendous challenge to the clinician, and, as presented here, even with appropriate antibiotics, there is a high rate of recurrence.