Surveillance of Extrapulmonary Nontuberculous Mycobacteria Infections

Oregon, USA, 2007-2012

Emily Henkle; Katrina Hedberg; Sean D. Schafer; Kevin L. Winthrop

Disclosures

Emerging Infectious Diseases. 2017;23(10):1627-1630. 

In This Article

Results

Patient Characteristics and Species Isolated

We identified 334 patients with extrapulmonary isolates, including 1 patient with 2 distinct infections. Overall, 176 (53%) patients were female, and the median age was 50 years (range 0.8–92 years) (Table). Half (n = 167, 50%) of patients had M. avium/intracellulare complex (MAC) infection, 129 (38.6%) RGM infection, and 21 (6.3%) M. marinum infection.

Results by Site of Infection

Among the 334 extrapulmonary NTM infections, 197 (59.0%) were skin/soft tissue, 57 (17.1%) were disseminated, 28 (8.4%) were lymph node, 14 (4.2%) were joint, and 38 (11.4%) were other (Table). The overall species distribution was 50% MAC, 22.8% M. chelonae/abscessus complex or M. chelonae, 9.6% M. fortuitum, and 6.3% M. marinum. We identified an additional 13 patients with M. gordonae isolates. Patients with skin/soft tissue infections were more commonly female (58%), whereas disseminated infections occurred predominantly in male patients (67%); of these, 79% of patients had MAC infection. The median age of patients with disseminated infections was 41 years, and 60% of these infections occurred in HIV-positive patients. Lymph node infections were 82.1% MAC; 18% of these patients were HIV positive. Among 23 HIV-negative patients with lymph node infections, 10 (44%) were <5 years of age. Only 14 joint infections were reported; these patients had a median age of 70 years, and 64.3% of infections were caused by MAC. Of other infections, 52.6% were caused by MAC and 31.6% by M. chelonae/abscessus complex or M. chelonae.

Estimates of Annual Incidence

The average annual incidence of extrapulmonary NTM infection during 2007–2012 was 1.5 (95% CI 1.1–1.8) cases/100,000 population. The incidence was 1.4 (CI 1.0–1.8) cases/100,000 population in 2007, peaked at 1.7 (CI 1.3–2.1)/100,000 in 2009, and decreased to 1.3 (CI 1.0–1.7)/100,000 in 2012 (Figure). The Poisson estimate of change in annual incidence was not significant, at −1.8% (95% CI −0.08 to 0.04; p = 0.6). The incidence by site of isolation was 0.9 cases/100,000 population for skin/soft tissue, 0.2/100,000 for disseminated, 0.2/100,000 for lymph, 0.1/100,000 for joint, and 0.2/100,000 other. The average annual incidence was 0.7 cases/100,000 population for MAC, 0.2/100,000 for M. abscessus/chelonae complex, and 0.1/100,000 each for M. fortuitum, M. chelonae, and M. marinum.

Figure.

Observed incidence (cases/100,000 population) of extrapulmonary nontuberculous mycobacterium infection (excluding Mycobacterium gordonae), Oregon, USA, 2007–2012.

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