title: Effect of Introducing Xpert MTB/RIF to Test and Treat Individuals at Risk of Multidrug-Resistant Tuberculosis in Kazakhstan: A Prospective Cohort Study.
abstract: BACKGROUND
  Xpert MTB/RIF (Xpert) was piloted in Kazakhstan to detect tuberculosis (TB) and rifampicin resistance (RR-)TB among individuals at risk of multidrug-resistant (MDR-) TB. This study assessed the performance of Xpert compared to conventional diagnostic methods, RR-TB case detection among various risk groups, treatment initiation and time to diagnosis and treatment.
  
  
  METHODS
  Eligible individuals were tested with Xpert, smear microscopy, culture and drug-susceptibility testing (DST) at the national TB reference laboratory and three provincial laboratories. Data was collected prospectively from August 2012 to May 2013 from routine laboratory and treatment registers.
  
  
  RESULTS
  A total of 5,611 Xpert tests were performed mostly targeting contacts of MDR-TB patients, 'other' presumptive MDR-TB patients, and retreatment cases (26%, 24% and 22%, respectively). Compared to phenotypic DST, the positive predictive value of Xpert to detect RR-TB was 93.1% and 96.4% and the negative predictive value was 94.6% and 92.7% using solid and liquid culture media, respectively. RR-TB detection was highest among (former) prisoners, retreatment cases, people living with HIV/AIDS (PLWHA), and TB patients with positive smears after intensive phase of treatment (59%, 58%, 54% and 53% among TB positives, respectively). 88.9% of RR-TB patients were registered to have started second-line TB treatment. Median time to diagnosis with Xpert was 0.0 days (IQR 0.0-1.0), time from diagnosis to start of first-line treatment 3.0 days (IQR 1.0-7.0), and to start of second-line treatment 7.0 days (IQR 4.0-16).
  
  
  CONCLUSIONS
  Compared to conventional culture and DST, Xpert had a shorter result turn-around-time and excellent concordance to detect RR-TB. Time from sputum collection to start of second-line treatment was reduced to one week. The yield of Xpert could be maximized by increasing referrals from penitentiary and HIV centers to TB centers.
authors.affiliation: KNCV Tuberculosis Foundation, Central Office, The Hague, Netherlands.
authors.forename: Sanne Christine
authors.initials: SC
authors.lastname: van Kampen
authors.affiliation: KNCV Tuberculosis Foundation, Central Asia Office, Almaty, Kazakhstan.
authors.forename: Aigul
authors.initials: A
authors.lastname: Tursynbayeva
authors.affiliation: National Center of Tuberculosis Control, Almaty, Kazakhstan.
authors.forename: Aliya
authors.initials: A
authors.lastname: Koptleuova
authors.forename: Zauresh
authors.initials: Z
authors.lastname: Murzakhmetova
authors.affiliation: Akmola Regional Tuberculosis Dispensary, Kokshetau, Kazakhstan.
authors.forename: Zauresh
authors.initials: Z
authors.lastname: Murzabekova
authors.affiliation: East Kazakhstan Regional Tuberculosis Dispensary, Oskemen, Kazakhstan.
authors.forename: Lyazzat
authors.initials: L
authors.lastname: Bigalieva
authors.affiliation: Almaty City Tuberculosis Dispensary, Almaty, Kazakhstan.
authors.forename: Moldir
authors.initials: M
authors.lastname: Aubakirova
authors.affiliation: KNCV Tuberculosis Foundation, Central Asia Office, Almaty, Kazakhstan.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Pak
authors.affiliation: KNCV Tuberculosis Foundation, Central Office, The Hague, Netherlands.
authors.forename: Susan
authors.initials: S
authors.lastname: van den Hof
mesh_terms: D000904:Antibiotics, Antitubercular / Q000627:therapeutic use; D015373:Bacterial Typing Techniques; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007623:Kazakhstan; D008297:Male; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D011446:Prospective Studies; D011933:Reagent Kits, Diagnostic / Q000706:statistics & numerical data*; D012293:Rifampin / Q000627:therapeutic use; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000188:drug therapy* / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000188:drug therapy* / Q000382:microbiology
chemical_list: D000904:Antibiotics, Antitubercular; D011933:Reagent Kits, Diagnostic; D012293:Rifampin