Application of diagnostic criteria for non-tuberculous mycobacterial disease to a case series of mycobacterial-positive isolates

Abstract

The American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA) have provided guidelines to assist in the accurate diagnosis of lung disease caused by nontuberculous mycobacteria (NTM). These microbiologic, radiographic, and clinical criteria are considered equally important and all must be met to make the diagnosis of NTM lung disease. To assess the significance of the three criteria, each was evaluated for its contribution to the diagnosis of NTM lung disease in a case series. Laboratory reports of any specimen positive for NTM isolation were collected between January 1, 2006 and December 31, 2010 at a university medical center. Medical records were reviewed in detail using a standardized form. The total number of patients with a culture from any site positive for NTM was 297 while the number from respiratory specimens during the same period was 232 (78%). Samples from two of these patients also yielded M. tuberculosis complex and were excluded. While 128 of the remaining 230 patients (55.7%) in the cohort met the microbiologic criterion for diagnosis of NTM lung disease, 151 (65.6%) and 189 (78.3%) met the radiologic and clinical criteria respectively. Only 78 patients (33.9%) met all three criteria provided by the ATS/IDSA for diagnosis of NTM lung disease. This evaluation reaffirms that defining NTM lung disease using either one or two of the criteria provided by the 2007 ATS/IDSA guidelines may significantly overestimate the number of cases of NTM lung disease. Based on the experience of defining NTM lung disease in this case series, recommendations for modification of the ATS/IDSA guidelines are provided which include expansion of both radiologic patterns and the list of symptoms associated with NTM lung disease.

Evaluation of a new culture medium for isolation of nontuberculous mycobacteria from environmental water samples

“…In the United States the annual incidence of NTM disease is thought to be 3.2–9.8 per 100,000 population [ 2 ] and the associated economic burden of hospitalization has been estimated to be $435 million per year [ 3 ]. There are over 150 known species of NTM and infection from pathogenic strains is increasing in frequency with the potential to cause severe infection in those most vulnerable [ 4 , 5 ]. Mycobacterium species have characteristics that make them difficult to control in building water systems even with on-site secondary disinfection.…”

“…mucogenicum clade [ 6 , 7 ]. NTM infections can be classified into four clinical presentations including chronic lung disease, lymphadenitis, cutaneous disease, and disseminated disease [ 5 ].…”

“…NTM can be recovered from a variety of engineered environments including aerosols from pools and spas, ice machines, potable water, instruments in healthcare settings, and in biofilms in water distribution systems [5,6]. Human disease most commonly occurs from exposure to potable water sources and, in healthcare environments, can be caused by at least 17 NTM species or complexes including M. abscessus clade, M. avium complex, M. chelonae, and M. mucogenicum clade [6,7].…”

“…Human disease most commonly occurs from exposure to potable water sources and, in healthcare environments, can be caused by at least 17 NTM species or complexes including M. abscessus clade, M. avium complex, M. chelonae, and M. mucogenicum clade [6,7]. NTM infections can be classified into four clinical presentations including chronic lung disease, lymphadenitis, cutaneous disease, and disseminated disease [5].…”

Development and clinical evaluation of a new multiplex PCR assay for a simultaneous diagnosis of tuberculous and nontuberculous mycobacteria

“…We should note that all five cases fulfilled the American Thoracic Society (ATS)’s definition of MAC disease, with MAC detected in at least two sputum samples collected at different times, a presence of TB/NTM infection-like respiratory symptoms (fever, cough, weight lost, night sweats) and M. tuberculosis not detected in the sputum samples. [27] The Multiplex assay in combination with the Xpert assay, could serve as a complement to the current diagnostic algorithm for patients with TB/NTM infection-like symptoms. For the pan-mycobacteria panel and “Other-NTM”, the clinical context is part of the diagnostic process, as patients have to fulfil the American Thoracic Society (ATS) diagnostic criteria for NTM disease described above.…”