title: Extensively drug-resistant tuberculosis: 2 years of surveillance in Iran.
abstract: BACKGROUND
  Extensively drug-resistant (XDR) tuberculosis (TB) is a cause of concern, because it renders patients untreatable with available drugs. In this study, we documented the existence and transmission of XDR TB among patients with multidrug-resistant TB. These patients were referred to the National Research Institute of Tuberculosis and Lung Diseases (Tehran, Iran) for treatment and diagnosis from 2003 to 2005.
  
  
  METHODS
  The sputum specimens from a total of 2030 patients with TB were digested, examined microscopically for acid-fast bacilli, and inoculated into Lowenstein-Jensen slants by standard procedures. Testing of susceptibility to first-line drugs was performed for 1284 Mycobacterium tuberculosis isolates. Subsequently, the strains that were identified as multidrug-resistant M. tuberculosis (113 isolates) were subjected to susceptibility testing for second-line drugs. Spoligotyping and restriction fragment-length polymorphism were performed for strains that were identified as XDR M. tuberculosis.
  
  
  RESULTS
  A total of 12 (10.9%) of 113 multidrug-resistant M. tuberculosis strains were resistant to all 8 second-line drugs tested and, therefore, were denoted as XDR M. tuberculosis. Retrospective analysis of the cases of XDR TB showed that all of them belonged to 1 of 2 epidemiological clusters, either a single-family cluster (4 cases) or a cluster of close contacts (8 cases). The strains were identified as belonging to the M. tuberculosis superfamilies Haarlem 1 and East African Indian 3.
  
  
  CONCLUSIONS
  The emergence of XDR TB cases in Iran highlights the need to reinforce the Iranian TB policy with regard to control and detection strategies.
authors.affiliation: National Research Institute of Tuberculosis and Lung Diseases, Tehran, Iran.
authors.forename: Mohamad Reza
authors.initials: MR
authors.lastname: Masjedi
authors.forename: Parissa
authors.initials: P
authors.lastname: Farnia
authors.forename: Setara
authors.initials: S
authors.lastname: Sorooch
authors.forename: Majid Valiollah
authors.initials: MV
authors.lastname: Pooramiri
authors.forename: Seyed Davood
authors.initials: SD
authors.lastname: Mansoori
authors.forename: Abolhasan Zia
authors.initials: AZ
authors.lastname: Zarifi
authors.forename: Ali
authors.initials: A
authors.lastname: Akbarvelayati
authors.forename: Sven
authors.initials: S
authors.lastname: Hoffner
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D006801:Humans; D007492:Iran; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000302:isolation & purification*; D012150:Polymorphism, Restriction Fragment Length; D018088:Tuberculosis, Multidrug-Resistant / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents