Disseminated Mycobacterium chelonei infection following cadaveric renal transplantation: favorable response to cefoxitin

Management of Mycobacterium Other than Tuberculosis in Solid Organ Transplantation

Mycobacteria other than tuberculosis are important pathogens to consider in solid organ transplant recipients. Delay in recognition and treatment may incur significant morbidity and mortality. Management of mycobacteria other than tuberculosis requires a knowledge of treatment specific for each species and drug-drug interactions between antimicrobial and immunosuppressive drugs. Therapy in solid organ transplant can be prolonged and may require a reduction in immunosuppression to improve outcomes.

Non-tuberculous mycobacterial infections in solid organ transplant recipients: An update

Non-tuberculous mycobacteria are ubiquitous environmental organisms that are now increasingly recognized as important causes of clinical disease in solid organ transplant recipients. Risk factors of non-tuberculous mycobacteria infection are severe immunologic defects and structural abnormalities. Lung transplant recipients are at higher risk for non-tuberculous mycobacterial disease compared to recipients of other solid organs. The clinical presentation could be skin and soft tissue infection, osteoarticular disease, pleuropulmonary infection, bloodstream (including catheter-associated) infection, lymphadenitis, and disseminated or multi-organ disease. Management of non-tuberculous mycobacteria infection is complex due to the prolonged treatment course with multi-drug regimens that are anticipated to interact with immunosuppressive medications. This review article provides an update on infections due to non-tuberculous mycobacteria after solid organ transplantation, and discusses the epidemiology, risk factors, clinical presentation, and management.

Nontuberculous mycobacterial infection in hematopoietic stem cell and solid organ transplant recipients

Nontuberculous mycobacteria (NTM) are ubiquitous environmental organisms. In immunocompetent hosts, they are a rare cause of disease. In immunocompromised hosts, disease due to NTM is well documented. Reports of NTM disease have increased in hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients. This increase may reflect increased numbers of transplants, intensification of immune suppressive regimens, prolonged survival of transplant recipients, and/or improved diagnostic techniques. The difficulty of diagnosis and the impact associated with infections due to NTM in HSCT and SOT recipients necessitates that, to ensure prompt diagnosis and early initiation of therapy, a high level of suspicion for NTM disease be maintained. The most common manifestations of NTM infection in SOT recipients include cutaneous and pleuropulmonary disease, and, in HSCT recipients, catheter-related infection. Skin and pulmonary lesions should be biopsied for histologic examination, special staining, and microbiologic cultures, including cultures for bacteria, Nocardia species, fungi, and mycobacteria. Mycobacterial infections associated with catheters may be documented by tunnel or blood (isolator) cultures. Susceptibility testing of mycobacterial isolates is an essential component of optimal care. The frequent isolation of NTM other than Mycobacterium avium complex (MAC) from transplant recipients limits the extrapolation of therapeutic data from human immunodeficiency virus-infected individuals to the population of transplant recipients. Issues involved in the management of NTM disease in transplant recipients are characterized by a case of disseminated infection due to Mycobacterium avium complex in a lung transplant recipient, with a review of the relevant literature.

A case of cutaneous Mycobacterium chelonae abscessus infection in a renal transplant patient

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 sporotrichoid 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.

Mycobacterium chelonae: a cause of nodular skin lesions with a proclivity for renal transplant recipients

PURPOSE

Infections due to Mycobacterium chelonae are uncommon. Several renal transplant recipients at our medical center have developed M. chelonae infections during the past several years, so we decided to review our recent experience with M. chelonae infections.

PATIENTS AND METHODS

The clinical microbiology laboratory records of four Vanderbilt University Affiliated Hospitals were reviewed. Ten patients with M. chelonae tissue or blood infections were identified between 1982 and July 1988.

RESULTS

All infections involved the skin and subcutaneous tissue. Three infections developed at the sites of medical injections. The remaining seven infections occurred in renal transplant recipients and produced a clinically distinctive syndrome. All were indolent tender nodular lesions on the extremities, usually the lower legs. Systemic symptoms were absent, and white blood cell counts were within normal limits. Diagnosis required tissue biopsy and cultures that were incubated for a month. Therapy consisted of surgical excision combined with long-term antibiotics. Even so, some patients had a chronic, relapsing course.

CONCLUSION

Although other diagnoses must be considered, the presumptive diagnosis of M. chelonae infection is suggested by the appearance of nodular erythematous lesions on the legs of a renal transplant recipient.