title: Epidemiology of Rifampicin Resistant Tuberculosis and Common Mutations in rpoB Gene of Mycobacterium tuberculosis: A Retrospective Study from Six Districts of Punjab (India) Using Xpert MTB/RIF Assay.
abstract: BACKGROUND
  Xpert MTB/RIF assay has revolutionized the diagnosis of tuberculosis (TB) by simultaneously detecting the bacteria and resistance to rifampicin (RIF), a surrogate marker for multidrug-resistant TB (MDR-TB) in <2 h. The RIF resistance pattern in Malwa region of Punjab, India, is not documented. Here, we report the epidemiology of RIF-resistant TB and mutations in rpoB gene of Mycobacterium tuberculosis (MTB).
  
  
  METHODS
  A total of 1612 specimens received between October 2013 and February 2015 were tested by Xpert MTB/RIF assay following manufacturer's instructions. The results thus obtained were analyzed using SPSS version 20.0.0 (SPSS Inc., Chicago, IL, USA) statistical software.
  
  
  RESULTS
  RIF resistance was statistically higher in previously treated patients in comparison to the new patients (P = 0.006) and in patients with acid fast-Bacilli (AFB) positive smears to AFB-negative smears (P = 0.048). RIF resistance mutations in 130 specimens revealed frequency of E 73/130 (56%), B 28/130 (21.5%), D 18/130 (13.8%), A 11/130 (8.4%), and C 1/130 (0.7%) while in one specimen, mutation combination, i.e., mutations associated with more than one probe (A and B both) was present.
  
  
  CONCLUSIONS
  Xpert MTB/RIF assay is a user-friendly screening tool for detection of MTB and RIF resistance from suspected TB/MDR cases in a shorter period of time. It could also serve as a useful technique to have simultaneous preliminary information regarding the mutation pattern of RIF resistance in MTB isolates.
authors.affiliation: Department of Microbiology, Guru Gobind Singh Medical College, Faridkot, Punjab, India.
authors.forename: Ramandeep
authors.initials: R
authors.lastname: Kaur
authors.affiliation: Department of Microbiology, Guru Gobind Singh Medical College, Faridkot, Punjab, India.
authors.forename: Neerja
authors.initials: N
authors.lastname: Jindal
authors.affiliation: Department of Microbiology, Guru Gobind Singh Medical College, Faridkot, Punjab, India.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Arora
authors.affiliation: Department of Microbiology, Guru Gobind Singh Medical College, Faridkot, Punjab, India.
authors.forename: Shajla
authors.initials: S
authors.lastname: Kataria
keywords: Epidemiology; Mycobacterium tuberculosis; Xpert MTB/RIF assay; multidrug-resistant tuberculosis; rifampicin resistance determining region