title: Increasing Recovery of Nontuberculous Mycobacteria from Respiratory Specimens over a 10-Year Period in a Tertiary Referral Hospital in South Korea.
abstract: BACKGROUND
  The number of patients with pulmonary disease caused by nontuberculous mycobacteria (NTM) has been increasing worldwide. The aim of this study was to evaluate long-term trends in the NTM recovery rate from respiratory specimens over a 10-year period in a tertiary referral hospital in South Korea.
  
  
  METHODS
  We retrospectively reviewed the records of mycobacterial cultures of respiratory specimens at Samsung Medical Center from January 2001 to December 2011.
  
  
  RESULTS
  During the study period, 32,841 respiratory specimens from 10,563 patients were found to be culture-positive for mycobacteria. These included 12,619 (38%) Mycobacterium tuberculosis and 20,222 (62%) NTM isolates. The proportion of NTM among all positive mycobacterial cultures increased from 43% (548/1,283) in 2001 to 70% (3,341/4,800) in 2011 (p<0.001, test for trend). The recovery rate of NTM isolates from acid-fast bacilli smear-positive specimens increased from 9% (38/417) in 2001 to 64% (1,284/1,997) in 2011 (p<0.001, test for trend). The proportion of positive liquid cultures was higher for NTM than for M. tuberculosis (p<0.001). The most frequently isolated NTM were Mycobacterium avium-intracellulare complex (53%) and Mycobacterium abscessus-massiliense complex (25%).
  
  
  CONCLUSIONS
  The recovery rate of NTM from respiratory specimens in South Korea has increased steadily.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Won-Jung
authors.initials: WJ
authors.lastname: Koh
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Boksoon
authors.initials: B
authors.lastname: Chang
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Byeong-Ho
authors.initials: BH
authors.lastname: Jeong
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Kyeongman
authors.initials: K
authors.lastname: Jeon
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Su-Young
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Ki
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: O Jung
authors.initials: OJ
authors.lastname: Kwon
keywords: Epidemiology; Korea; Mycobacterium tuberculosis; Nontuberculous Mycobacteria