Outbreaks of nontuberculous mycobacteria

The purpose of this review is to summarize the emerging literature on nontuberculous mycobacteria outbreaks in healthcare settings. As our ability to identify mycobacterial species develops, we are better able to recognize epidemiologic connections and better understand the prevalence and importance of these outbreaks and pseudo-outbreaks in healthcare settings.

The number of outbreaks related to nontuberculous outbreaks is increasing because of heightened awareness and better diagnostic tests for species level identification of mycobacteria. Outbreaks in healthcare settings have been related to cardiac surgery, plastic surgery, including medical tourism, colonized humidifiers and heater-cooler devices, imperfect disinfection, and hospital water sources. Mycobacteria have a predilection to form biofilms, are resistant to disinfection and are prevalent in hospital water systems. Patients with structural lung disease like cystic fibrosis patients are at particularly high risk for mycobacterial infection. It has been thought that acquisition in this patient population is from common environmental exposure; however, there is increasing evidence that transmission in this patient population can occur through either direct or indirect patient-to-patient spread.

Mycobacteria outbreaks in healthcare settings have been underrecognized. As we identify additional clusters of infection with better diagnostic tools and heightened awareness, we will likely need better infection control practices to prevent infections in healthcare settings.