title: Frequency of mutations in rifampicin and isoniazid resistant isolates ofM. tuberculosis: an analysis from Central India.
abstract: BACKGROUND
  The spread of drug-resistant tuberculosis has challenged tuberculosis control strategies globally. The present study aims to analyze the frequency of mutations inrpoB,katGandinhAgenes in strains ofM. tuberculosiscomplex (MTBC) circulating in Central India. It is anticipated that the findings may provide a starting point to understand the evolutionary success of drug-resistant strains of MTBC in this region.
  
  
  METHODS
  Line probe assay was carried out on 720 consecutive sputum samples of MDR suspects from June 2012 to May 2013. Mutation frequencies in therpoB,katGandinhAgenes were analyzed.
  
  
  RESULTS
  Mutations were identified in 269 (37.6%) samples, as follows: 55 (7.6%) samples had mutations conferring resistance to only isoniazid, 84 (11.6%) had mutations conferring resistance to only rifampicin and 130 (18%) isolates had mutations conferring resistance to both isoniazid and rifampicin. The most frequent mutation in therpoBgene was at codon S531L, seen in 141 (19.5%) isolates. The most frequent mutation in thekatGgene was at codon S315T1, seen in 151 (20.9%) isolates; and in theinhAgene at codon C15T, seen in 21 (2.9%) isolates. Some unidentified mutations were also observed.
  
  
  CONCLUSIONS
  The patterns and the frequency of the mutations identified in this study indicate the most frequent mutations at S531L codon in therpoBgene, S315T1 codon in thekatGgene and C15T codon in the promoter region of theinhAgene. Controlling the emergence and spread of MDR TB requires an understanding of the evolution of these mutations.
authors.affiliation: MD, National Reference Laboratory, Department of Microbiology, Bhopal Memorial Hospital and Research Center, Bhopal, Madhya Pradesh, India.
authors.forename: Prabha
authors.initials: P
authors.lastname: Desikan
authors.affiliation: MS, Intermediate Reference Laboratory, MRTB Hospital & Chest Center, Indore, Madhya Pradesh, India.
authors.forename: Atul
authors.initials: A
authors.lastname: Kharate
authors.affiliation: MSc, National Reference Laboratory, Bhopal Memorial Hospital and Research Center, Bhopal, Madhya Pradesh, India.
authors.forename: Nikita
authors.initials: N
authors.lastname: Panwalkar
authors.affiliation: PhD, Intermediate Reference Laboratory, MRTB Hospital & Chest Center, Indore, Madhya Pradesh, India.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Khurana
authors.affiliation: MSc, National Reference Laboratory, Bhopal Memorial Hospital and Research Center, Bhopal, Madhya Pradesh, India.
authors.forename: Shaina Beg
authors.initials: SB
authors.lastname: Mirza
authors.affiliation: MSc, National Reference Laboratory, Bhopal Memorial Hospital and Research Center, Bhopal, Madhya Pradesh, India.
authors.forename: Aparna
authors.initials: A
authors.lastname: Chaturvedi
authors.affiliation: MSc, National Reference Laboratory, Bhopal Memorial Hospital and Research Center, Bhopal, Madhya Pradesh, India.
authors.forename: Reeta
authors.initials: R
authors.lastname: Varathe
authors.affiliation: MSc, National Reference Laboratory, Bhopal Memorial Hospital and Research Center, Bhopal, Madhya Pradesh, India.
authors.forename: Manju
authors.initials: M
authors.lastname: Chourey
authors.affiliation: MSc, National Reference Laboratory, Bhopal Memorial Hospital and Research Center, Bhopal, Madhya Pradesh, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
authors.affiliation: MSc, National Reference Laboratory, Bhopal Memorial Hospital and Research Center, Bhopal, Madhya Pradesh, India.
authors.forename: Nitin
authors.initials: N
authors.lastname: Doshi
authors.affiliation: MSc, National Reference Laboratory, Bhopal Memorial Hospital and Research Center, Bhopal, Madhya Pradesh, India.
authors.forename: Manoj
authors.initials: M
authors.lastname: Pandey
keywords: Central India; M. tuberculosis; Mutation; frequency