title: Duration of Pulmonary Tuberculosis Infectiousness under Adequate Therapy, as Assessed Using Induced Sputum Samples.
abstract: BACKGROUND
  A sputum culture is the most reliable indicator of the infectiousness of pulmonary tuberculosis (PTB); however, a spontaneous sputum specimen may not be suitable. The aim of this study was to evaluate the infectious period in patients with non-drug-resistant (DR) PTB receiving adequate standard chemotherapy, using induced sputum (IS) specimens.
  
  
  METHODS
  We evaluated the duration of infectiousness of PTB using a retrospective cohort design.
  
  
  RESULTS
  Among the 35 patients with PTB, 22 were smear-positive. The rates of IS culture positivity from baseline to the sixth week of anti-tuberculosis medication in the smear-positive PTB group were 100%, 100%, 91%, 73%, 36%, and 18%, respectively. For smear-positive PTB cases, the median time of conversion to culture negativity was 35.0 days (range, 28.0-42.0 days). In the smear-negative PTB group (n=13), the weekly rates of positive IS culture were 100%, 77%, 39%, 8%, 0%, and 0%, respectively, and the median time to conversion to culture-negative was 21.0 days (range, 17.5-28.0 days).
  
  
  CONCLUSIONS
  The infectiousness of PTB, under adequate therapy, may persist longer than previously reported, even in patients with non-DR PTB.
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.; Lung Research Institute, Hallym University College of Medicine, Chuncheon, Korea.; Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Inje University Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
authors.forename: Yousang
authors.initials: Y
authors.lastname: Ko
authors.affiliation: Department of Laboratory Medicine, Inje University Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
authors.forename: Jeong Hwan
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Inje University Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
authors.forename: Hyun-Kyung
authors.initials: HK
authors.lastname: Lee
authors.affiliation: Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Young Seok
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.; Lung Research Institute, Hallym University College of Medicine, Chuncheon, Korea.
authors.forename: Suh-Young
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.; Lung Research Institute, Hallym University College of Medicine, Chuncheon, Korea.
authors.forename: So Young
authors.initials: SY
authors.lastname: Park
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.; Lung Research Institute, Hallym University College of Medicine, Chuncheon, Korea.
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Mo
authors.affiliation: Department of Internal Medicine, Jeju National University Hospital, Jeju, Korea.
authors.forename: Changhwan
authors.initials: C
authors.lastname: Kim
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.; Lung Research Institute, Hallym University College of Medicine, Chuncheon, Korea.
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Park
keywords: Induced Sputum; Infectious Disease Incubation Period; Mycobacterium tuberculosis; Tuberculosis, Pulmonary