Isolation Trend of Nontuberculosis Mycobacteria at a Tertiary-care Hospital in 2003-2011

Yang, Hee Young

Abstract

OBJECTIVES
This study was performed to investigate the prevalence of nontuberculous mycobacteria (NTM) species and to determine the clinical significance of NTM isolates.
METHODS
From January 2003 to July 2011, NTMs were identified using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or reverse blot hybridization assay (REBA). And pulmonary NTM infection was diagnosed by clinical history, underlying disease, radiological and microbiological findings according to the diagnostic criteria of 2007 American Thoracic Society (ATS).
RESULTS
Of the 697 AFB culture-positive specimens, NTM was detected in 149 (21.4%) specimens. Among 154 NTM isolates from 149 specimens, M. avium-intracellulare complex (MAC) (48.1%) was the most frequently isolated organisms followed by M. abscessus (13.6%), M. gordonae (9.1%), M. kansasii (8.4%), M. szulgai (3.9%), M. fortuitum complex (3.3%), M. scrofulaceum (2.0%), M. malmoense (1.3%), M. chelonae (1.3%), M. marinum (1.3%), M. genavense (1.3%), M. lentiflavum (1.3%) and M. mucogenicum (0.6%). Among 147NTM isolates from 142 respiratory specimens, 54 NTM isolates (36.7%) were causative organisms in NTM pulmonary infection.
CONCLUSIONS
The isolation rate of NTM was 21.4% in clinical specimen, and in some cases NTM species results in pulmonary NTM infection. Because the treatment of pulmonary NTM infection depends on the infecting species, accurate identification and clinical significance of NTM are required for adequate treatment.