Chest
Volume 129, Issue 2, February 2006, Pages 341-348
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Original Research
Clinical Significance of Nontuberculous Mycobacteria Isolated From Respiratory Specimens in Korea

https://doi.org/10.1378/chest.129.2.341Get rights and content

Study objectives

Precise epidemiologic data regarding nontuberculous mycobacterial (NTM) lung infection in many Asian countries have been relatively unavailable. In order to determine the clinical significance of NTM isolated from respiratory specimens, we reviewed medical records from all patients from whom NTM isolates were recovered within a 2-year period.

Materials and methods

We identified all NTM isolates from respiratory specimens at the Samsung Medical Center (Seoul, South Korea) obtained from January 2002 to December 2003. We then reviewed the clinical and radiologic characteristics of the patients from whom NTM was isolated. Patients were classified as having either definite, probable, or unlikely NTM lung disease, as defined by the guidelines of both the American Thoracic Society and the British Thoracic Society.

Results

During the study period, 1,548 NTM isolates were recovered from 794 patients. Of these 794 patients, 131 patients (17%) were determined to have definite NTM lung disease, and 64 patients (8%) were designated as probable disease candidates. The most commonly involved organisms in the definite and probable NTM lung disease cases were Mycobacterium avium complex (n = 94, 48%) and Mycobacterium abscessus (n = 64, 33%). In 195 patients with NTM lung disease, 82 patients (42%) manifested the upper lobe cavitary form, 101 patients (52%) exhibited the nodular bronchiectatic form, and 12 patients (6%) exhibited the unclassifiable form.

Conclusions

About one fourth of the patients in whom NTM was isolated from respiratory specimens were found to have clinically significant NTM lung infections. The spectrum of organisms responsible for the NTM lung disease in these Korean patients differed from those reported in other regions of the world. However, the estimates of clinical significance in this study may be underestimates due to the retrospective analysis. Some of the patients might have “true” NTM lung disease that could be diagnosed with continued evaluation and follow-up.

Section snippets

Study Subjects

All consecutive isolates from a mycobacterial laboratory at the Samsung Medical Center (a 1,250-bed tertiary referral hospital in Seoul, South Korea) during the 2-year period from January 2002 to December 2003 were collected and analyzed. All identified NTM isolates were considered to be significant, with the exception of Mycobacterium gordonae, a well-known environmental contaminant.31314 Patients with culture findings positive for M gordonae were included in the study only if multiple

Frequency of NTM Isolates

From 2002 to 2003, cultures of 1,548 respiratory specimens from 794 patients were found to be positive for NTM. The source of the isolate was sputum (n = 1,383, 89%), bronchial wash (n = 139, 9%), or lung tissue (n = 26, 2%). The mean age of the 794 patients was 56 ± 15 years (± SD). In 1,548 NTM isolates, the most frequently isolated organisms were Mycobacterium avium complex (n = 491, 32%), Mycobacterium abscessus (n = 442, 29%), and Mycobacterium fortuitum complex (n = 268, 17%) [Table 1].

Discussion

NTMs were first observed shortly after the discovery by Koch of the tubercle bacillus3 and were believed to represent environmental contamination or colonization; it was not until the 1950s that NTM were identified as potential pathogens. Since that time, these organisms have been implicated in an increasingly large proportion of pulmonary infections throughout the world, in both immunocompetent and immunocompromised hosts.1718192021 The reasons for this increasing rate of NTM lung disease are

ACKNOWLEDGMENT

We thank Eun-Mi Park, Shin-Hye Lee, and Eun Joo Kim for technical assistance.

References (37)

  • WolinskyE

    Nontuberculous mycobacteria and associated diseases

    Am Rev Respir Dis

    (1979)
  • HongYP et al.

    The seventh nationwide tuberculosis prevalence survey in Korea, 1995

    Int J Tuberc Lung Dis

    (1998)
  • van CrevelR et al.

    The impact of nontuberculous mycobacteria on management of presumed pulmonary tuberculosis

    Infection

    (2001)
  • KohWJ et al.

    Nontuberculous mycobacterial pulmonary diseases in immunocompetent patients

    Korean J Radiol

    (2002)
  • HanD et al.

    Radiographic and CT findings of nontuberculous mycobacterial pulmonary infection caused byMycobacterium abscessus.

    AJR Am J Roentgenol

    (2003)
  • JeongYJ et al.

    Nontuberculous mycobacterial pulmonary infection in immunocompetent patients: comparison of thin-section CT and histopathologic findings

    Radiology

    (2004)
  • KohWJ et al.

    Bilateral bronchiectasis and bronchiolitis at thin-section CT: diagnostic implications in nontuberculous mycobacterial pulmonary infection

    Radiology

    (2005)
  • KimTS et al.

    Hypothesis on the evolution of cavitary lesions in nontuberculous mycobacterial pulmonary infection: thin-section CT and histopathologic correlation

    AJR Am J Roentgenol

    (2005)
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    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

    This work was supported by grant R11–2002-103 from the Korea Science and Engineering Foundation.

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