title: Clinical Significance of Mycobacterium kansasii Isolates from Respiratory Specimens.
abstract: The clinical significance of Mycobacterium kansasii respiratory isolates is uncertain. The aims of this study were to determine the clinical relevance of M. kansasii isolates and to identify the clinical features and outcomes of M. kansasii lung disease. We reviewed the medical records of 104 patients from whom at least one respiratory M. kansasii isolate was obtained from January 2003 to July 2014 at Samsung Medical Center, South Korea. Of these 104 patients, 54 (52%) met the diagnostic criteria for nontuberculous mycobacterial lung disease; among them, 41 (76%) patients received antibiotic treatment for a median time of 15.0 months (interquartile range [IQR], 7.0-18.0 months). The remaining 13 (24%) without overt disease progression were observed for a median period of 24.0 months (IQR, 5.0-34.5 months). Patients with M. kansasii lung disease exhibited various radiographic findings of lung disease, including the fibrocavitary form (n = 24, 44%), the nodular bronchiectatic form (n = 17, 32%), and an unclassifiable form (n = 13, 24%). The fibrocavitary form was more common in patients who received treatment (n = 23, 56%), while the nodular bronchiectatic form was more common in patients with M. kansasii lung disease who did not receive treatment (n = 9, 70%). None of the patients with a single sputum isolate (n = 18) developed M. kansasii disease over a median follow-up period of 12.0 months (IQR, 4.0-26.5 months). In total, 52% of all patients with M. kansasii respiratory isolates exhibited clinically significant disease. Moreover, patients with M. kansasii lung disease displayed diverse radiographic findings in addition to the fibrocavitary form. The nodular bronchiectatic form was more common in patients with M. kansasii lung disease with an indolent clinical course. Thus, since the clinical significance of a single M. kansasii respiratory isolate is not definite, strict adherence to recommended diagnostic criteria is advised.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Seong Mi
authors.initials: SM
authors.lastname: Moon
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Hye Yun
authors.initials: HY
authors.lastname: Park
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South 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, South Korea.
authors.forename: Su-Young
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Myung Jin
authors.initials: MJ
authors.lastname: Chung
authors.affiliation: Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Hee Jae
authors.initials: HJ
authors.lastname: Huh
authors.affiliation: Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Ki
authors.affiliation: Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Lee
authors.affiliation: Department of Microbiology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Sung Jae
authors.initials: SJ
authors.lastname: Shin
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Won-Jung
authors.initials: WJ
authors.lastname: Koh
mesh_terms: D000328:Adult; D000368:Aged; D018450:Disease Progression; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D009165:Mycobacterium Infections, Nontuberculous / Q000382:microbiology*; D019909:Mycobacterium kansasii / Q000302:isolation & purification*; D056910:Republic of Korea; D012137:Respiratory System / Q000382:microbiology*; D013183:Sputum / Q000382:microbiology*