title: Molecular analysis of clinical isolates previously diagnosed as Mycobacterium intracellulare reveals incidental findings of "Mycobacterium indicus pranii" genotypes in human lung infection.
abstract: BACKGROUND
  Mycobacterium intracellulare is a major cause of Mycobacterium avium complex lung disease in many countries. Molecular studies have revealed several new Mycobacteria species that are closely related to M. intracellulare. The aim of this study was to re-identify and characterize clinical isolates from patients previously diagnosed with M. intracellulare lung disease at the molecular level.
  
  
  METHODS
  Mycobacterial isolates from 77 patients, initially diagnosed with M. intracellulare lung disease were re-analyzed by multi-locus sequencing and pattern of insertion sequences.
  
  
  RESULTS
  Among the 77 isolates, 74 (96 %) isolates were designated as M. intracellulare based on multigene sequence-based analysis. Interestingly, the three remaining strains (4 %) were re-identified as "Mycobacterium indicus pranii" according to distinct molecular phylogenetic positions in rpoB and hsp65 sequence-based typing. In hsp65 sequevar analysis, code 13 was found in the majority of cases and three unreported codes were identified. In 16S-23S rRNA internal transcribed spacer (ITS) sequevar analysis, all isolates of both species were classified within the Min-A ITS sequevar. Interestingly, four of the M. intracellulare isolates harbored IS1311, a M. avium-specific element. Two of three patients infected with "M. indicus pranii" had persistent positive sputum cultures after antibiotic therapy, indicating the clinical relevance of this study.
  
  
  CONCLUSIONS
  This analysis highlights the importance of precise identification of clinical isolates genetically close to Mycobacterium species, and suggests that greater attention should be paid to nontuberculous mycobacteria lung disease caused by "M. indicus pranii".
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. suyoung5505@hanmail.net.
authors.forename: Su-Young
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. hyeyunpark@skku.edu.
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. myacousticlung@gmail.com.
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, South Korea. kjeon@skku.edu.
authors.forename: Kyeongman
authors.initials: K
authors.lastname: Jeon
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. heejae.huh@samsung.com.
authors.forename: Hee Jae
authors.initials: HJ
authors.lastname: Huh
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. changski@skku.edu.
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Ki
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. mrmicro@skku.edu.
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Lee
authors.affiliation: Department of Microbiology, Institute for Immunology and Immunological Diseases, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea. hansjung@yuhs.ac.
authors.forename: Seung-Jung
authors.initials: SJ
authors.lastname: Han
authors.affiliation: Department of Microbiology, Institute for Immunology and Immunological Diseases, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea. sjshin@yuhs.ac.
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. wjkoh@skku.edu.
authors.forename: Won-Jung
authors.initials: WJ
authors.lastname: Koh
mesh_terms: D000368:Aged; D001426:Bacterial Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics; D001483:Base Sequence; D004251:DNA Transposable Elements; D005260:Female; D005838:Genotype; D006801:Humans; D008171:Lung Diseases / Q000175:diagnosis* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D009161:Mycobacterium / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D015269:Mycobacterium avium Complex / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D015270:Mycobacterium avium-intracellulare Infection / Q000175:diagnosis* / Q000382:microbiology; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014057:Tomography, X-Ray Computed
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D012336:RNA, Ribosomal, 16S