title: Prevalence of extensively drug-resistant tuberculosis among patients with multidrug-resistant tuberculosis: a retrospective hospital-based study.
abstract: OBJECTIVE
  Extensively drug-resistant tuberculosis (XDR-TB) is a difficult-to-treat form of multidrug-resistant tuberculosis (MDR-TB). High rates of XDR-TB have been reported from India. We sought to ascertain the prevalence of XDR-TB among patients with MDR-TB treated at a tertiary care centre in New Delhi, India.
  
  
  METHODS
  Case records of patients treated for MDR-TB at the All India Institute of Medical Sciences hospital, New Delhi, between 1997 and 2003 were retrospectively reviewed. All patients underwent a pretreatment drug-susceptibility testing (DST) to first- as well as second-line drugs. XDR-TB was defined as TB caused by bacilli showing resistance to rifampicin and isoniazid in addition to any fluoroquinolone and to at least one of the three following injectable drugs: capreomycin, kanamycin, and amikacin.
  
  
  RESULTS
  A total of 211 laboratory-confirmed cases of MDR-TB were reviewed. The mean age of the patients was 33 +/- 12 yr. Fifty one (24%) patients were females. All patients were sero-negative for human immunodeficiency virus infection. Five of the 211 MDR-TB patients had XDR-TB. The prevalence of XDR-TB was 2.4 per cent among MDR-TB patients.
  
  
  CONCLUSIONS
  Our results showed that XDR-TB was rare among patients with MDR-TB treated between 1997 and 2003 at our centre. Unreported selection bias might have been responsible for the high prevalence of XDR-TB reported in previous hospital-based studies from India.
authors: Department of Medicine, All India Institute of Medical Sciences, New Delhi, India. sksharma@aiims.ac.in
authors: Surendra K
authors: SK
authors: Sharma
authors: Ninoo
authors: N
authors: George
authors: Tamilarasu
authors: T
authors: Kadhiravan
authors: Pradip K
authors: PK
authors: Saha
authors: Hemant K
authors: HK
authors: Mishra
authors: Mahmud
authors: M
authors: Hanif
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use; D054908:Extensively Drug-Resistant Tuberculosis / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D006761:Hospitals; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents