Rapidly Growing Mycobacterial Infections in Transplant: Evolving Epidemiology and Treatment Options
Rapidly growing mycobacteria (RGM) are environmental microorganisms that thrive in water-associated biofilms and grow more quickly in the laboratory than slow-growing nontuberculous mycobacteria. Prevalence of RGM infection appears to be increasing, and patients with structural lung disease and immunocompromised hosts, especially patients with cystic fibrosis or lung transplant recipients, are at increased risk. Transplant recipients can acquire RGM from the community or from healthcare facilities, and several recent RGM outbreaks have occurred at hospitals with transplant programs. Diagnosis of RGM infection in transplant patients is challenging and often delayed due to indolent, atypical presentations and decreased sensitivity of culture. Treatment requires prolonged combination antimicrobial therapy, and many invasive RGM infections also require surgical debridement. Even with aggressive therapy, however, transplant patients with RGM infections commonly fail to achieve cure, and antibiotic-related toxicities are common. Development of more effective and better-tolerated therapies for both transplant recipients and candidates for transplantation with RGM infection represents an emerging need. In addition, close adherence to infection prevention measures is critical; strategies for prevention should be based upon local RGM and transplant epidemiology.