title: A retrospective analysis of isoniazid-monoresistant tuberculosis: among Iranian pulmonary tuberculosis patients.
abstract: OBJECTIVE
  Isoniazid (INH) is one of the most potent anti-tuberculosis (TB) drugs. The spread and transmission of INH- resistant bacilli are likely to pose a significant problem for National TB control Program (NTP). In this study, we aimed to determine the trend of INH-monoresistant TB in Iran.
  
  
  METHODS
  The susceptibility patterns of Mycobacterium tuberculosis (MTB) strains that were isolated from clinical samples were retrospectively analyzed (January 2003-December 2011). Identification and drug susceptibility testing (DST) were performed using both conventional and molecular methods. The associated risk factors were assessed using the Chi-square test.
  
  
  RESULTS
  Out of 4825 culture-positive isolates, 6.1% were resistant to INH, with an increasing trend over the study period. The INH-monoresistance from 4.4 in 2003 reached to 9.4% in 2011. Among the studied risk factors, age was significantly associated with INH-monoresistance (p < 0.05).
  
  
  CONCLUSIONS
  The increased trend in INH-monoresistance underlines the need for greater enforcement of national TB control programs. In this regard, better management of TB cases, establishing advanced diagnostic facilities and use of standard treatment regimens are recommended to avoid further emergence of INH resistant cases.
authors.affiliation: Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Varahram
authors.affiliation: Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Nasiri
authors.affiliation: Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Parissa
authors.initials: P
authors.lastname: Farnia
authors.affiliation: Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohadese
authors.initials: M
authors.lastname: Mozafari
authors.affiliation: Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Velayati
keywords: Drug resistance; Iran; Mycobacterium tuberculosis.; isoniazid