Extrapulmonary Nontuberculous Mycobacteria Infections in Hospitalized Patients

United States, 2009-2014

Emily E. Ricotta; Jennifer Adjemian; Rebekah A. Blakney; Yi Ling Lai; Sameer S. Kadri; D. Rebecca Prevots

Disclosures

Emerging Infectious Diseases. 2021;27(3):845-852. 

In This Article

Abstract and Introduction

Abstract

Nontuberculous mycobacteria (NTM) cause pulmonary and extrapulmonary infections in susceptible persons. To characterize the epidemiology of skin and soft tissue (SST) and disseminated extrapulmonary infections caused by NTM in the United States, we used a large electronic health record database to examine clinical, demographic, and laboratory data for hospitalized patients with NTM isolated from extrapulmonary sources during 2009–2014. Using all unique inpatients as the denominator, we estimated prevalence and summarized cases by key characteristics. Of 9,196,147 inpatients, 831 had confirmed extrapulmonary NTM. The 6-year prevalence was 11 cases/100,000 inpatients; source-specific prevalence was 4.4 SST infections/100,000 inpatients and 3.7 disseminated infections/100,000 inpatients. NTM species varied across geographic region; rapidly growing NTM were most prevalent in southern states. Infection with Mycobacterium avium complex was more common among patients with concurrent HIV and fungal infection, a relevant finding because treatment is more effective for M. avium complex than for other NTM infections.

Introduction

Nontuberculous mycobacteria (NTM) are opportunistic bacteria that are abundant in soil and water, including natural and plumbing-associated water sources.[1,2] For a minority of susceptible persons, exposure to NTM can result in extrapulmonary infections,[3] including skin, joint, lymph node, and disseminated infections. Extrapulmonary infections, especially disseminated disease, typically occur among persons with congenital or acquired immunodeficiencies (e.g., HIV infection)[4] but can also be associated with medical or cosmetic procedures that expose a wound to sources contaminated with mycobacteria.[5,6] A recently described outbreak identified disseminated infections with Mycobacterium chimaera after open heart surgery, arising from contamination of heater–cooler units.[6]

Few studies describe the epidemiology of extrapulmonary NTM in the United States at the national level. One recent study in Oregon evaluated the prevalence of extrapulmonary NTM by using statewide population-based laboratory surveillance data for 2007–2012, which included data for pulmonary and extrapulmonary NTM.[4] The researchers estimated a stable annual incidence of extrapulmonary NTM infection of 1.5 cases/100,000 population. The average age of extrapulmonary NTM patients (median 51 years) was younger than that of pulmonary NTM patients. In addition, rapidly growing NTM species were identified at a much greater frequency in extrapulmonary than in pulmonary NTM patients and represented one third of all cases in Oregon.[4] Epidemiologic studies of pulmonary NTM disease show tremendous geographic variation in prevalence and mycobacterial species,[7,8] suggesting the possibility of differences for extrapulmonary NTM as well, given the environmental influences on NTM disease dynamics. To characterize the epidemiology of skin and soft tissue (SST) and disseminated NTM infections and evaluate regional differences in incidence and mycobacterial species distribution, we examined laboratory-confirmed cases from a large electronic health record (EHR)–based repository of inpatient encounters from a national sample of US hospitals.

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