Nocardia-induced granulocyte macrophage colony-stimulating factor is neutralized by autoantibodies in disseminated/extrapulmonary nocardiosis.

BACKGROUND: Nocardia species cause infections in both immunocompromised and otherwise immunocompetent patients, although the mechanisms defining susceptibility in the latter group are elusive. Anticytokine autoantibodies are an emerging cause of pathogen-specific susceptibility in previously healthy human immunodeficiency virus-uninfected adults, including anti-granulocyte macrophage colony-stimulating factor (GM-CSF) autoantibodies with cryptococcal meningitis. METHODS: Plasma from patients with disseminated/extrapulmonary nocardiosis and healthy controls was screened for anticytokine autoantibodies using a particle-based approach. Autoantibody function was assessed by intranuclear staining for GM-CSF-induced STAT5 phosphorylation in normal cells incubated with either patient or normal plasma. GM-CSF-mediated cellular activation by Nocardia was assessed by staining for intracellular cytokine production and intranuclear STAT5 phosphorylation. RESULTS: We identified neutralizing anti-GM-CSF autoantibodies in 5 of 7 patients studied with central nervous system nocardiosis and in no healthy controls (n = 14). GM-CSF production was induced by Nocardia in vitro, suggesting a causative role for anti-GM-CSF autoantibodies in Nocardia susceptibility and dissemination. CONCLUSIONS: In previously healthy adults with otherwise unexplained disseminated/extrapulmonary Nocardia infections, anti-GM-CSF autoantibodies should be considered. Their presence may suggest that these patients may be at risk for later development of pulmonary alveolar proteinosis or other opportunistic infections, and that patients may benefit from therapeutic GM-CSF administration.

Isolation of Rapidly Growing Nontuberculous Mycobacteria in Wounds Following Combat-Related Injury.

OBJECTIVES: Rapidly growing nontuberculous mycobacteria (RGNTM) have yet to be described in combat-related injuries. This study investigates the epidemiology, clinical findings, treatment, and outcomes of RGNTM infections among combat casualties wounded in Afghanistan from 2010 to 2012. METHODS: Patients with RGNTM were identified from the Department of Defense Trauma Registry through the Trauma Infectious Disease Outcomes Study. Trauma history, surgical management, and clinical data were collected. Six isolates from patients requiring antimycobacterial therapy were sequenced. RESULTS: Seventeen cases were identified. Six cases, predominantly associated with Mycobacterium abscessus, required aggressive debridement and a median of 180 days of multidrug antimycobacterial therapy that included clofazimine. M. abscessus isolates expressed the erythromycin resistance methylase (erm(41)) gene for inducible macrolide resistance, yet there were no clinical treatment failures when macrolides were utilized in combination therapy. No clonal similarity between M. abscessus isolates was found. Eleven cases had positive wound cultures, but did not require antimycobacterial therapy. The median duration of time of injury to first detection of a RGNTM was 57 days. CONCLUSIONS: This represents the first report of RGNTM infections in war-wounded patients. RGNTM should be recognized as potential pathogens in grossly infected combat wounds. Surgical debridement and multidrug antimycobacterial therapy, when clinically indicated, was associated with satisfactory clinical outcomes.