The number of Nocardia infections is increasing and it may be associated with non-cystic fibrosis bronchiectasis, according to researchers.
Findings from their study were published in the journal Annals of the American Thoracic Society in an article titled “Increasing Nocardia Incidence Associated With Bronchiectasis At A Tertiary Care Center.”
Nocardiosis is an opportunistic infection caused by the bacteria Nocardia. Immunosuppressed patients often acquire this infection, affecting the lungs, skin and/or the central nervous system (CNS).
To study the incidence of Nocardia over time, researchers analyzed the medical records of patients at Duke University Hospital in Durham, North Carolina, who had at least one positive culture from a bodily fluid or tissue specimen for Nocardia between January 1996 and December 2013.
The analysis identified 183 patients positive for Nocardia — 44 from 1996 to 2001; 64 from 2002 to 2007; and 75 from 2008 to 2013. Among these patients, 56% were immunocompromised, mainly because they were receiving treatment after solid organ or hematopoietic cell transplant (30%).
Nocardia infection was mostly restricted to the lungs (62% of patients), but was also detected in other organs such as the skin (10%), brain (2%), other sites (6%), and at multiple sites (17%).
Among the immunocompromised patients, 10% had bronchiectasis. In fact, the incidence of Nocardia significantly increased in these patients over time, but there was no significant change among patients who had received stem cell or solid organ transplants.
Nocardia incidence was also higher among bronchiectasis patients using inhaled corticosteroids, but this association was not statistically significant.
“Nocardia cases at our center increased significantly between 1996 and 2013,” the researchers wrote. “This increase was primarily driven by patients with bronchiectasis and Nocardia pulmonary infection, rather than by an increase in immunocompromised populations. … In contrast, the incidence among transplant patients, our single largest population of immunocompromised patients, was stable over the same period.”
The researchers said the study raises concerns “about the potential for increasing Nocardia incidence, particularly among patients with bronchiectasis.”
“As Medicare claims data demonstrate a steady rise in the prevalence of bronchiectasis, particularly in elderly patients, it will be important to conduct ongoing surveillance on the epidemiology of Nocardia infection,” they added. “Further understanding of risk factors for Nocardia, particularly the role of inhaled corticosteroids, and treatment outcomes will be needed.”