title: Genotypic characterization of drug-resistant Mycobacterium tuberculosis isolates from Peru.
abstract: METHODS
  Twenty-nine epidemiological unrelated and mostly multidrug-resistant Mycobacterium tuberculosis (MDR-TB) strains from Peruvian patients.
  
  
  OBJECTIVE
  To investigate the molecular genetics of MDR-TB strains recovered in a Latin American country.
  
  
  METHODS
  Antimicrobial agent susceptibility testing, major genetic group designation, IS6110 fingerprinting, spoligotyping, and automated deoxyribonucleic acid sequencing of regions of the katG, rpoB, embB, gyrA, and pncA genes with mutations commonly associated with drug resistance.
  
  
  RESULTS
  Nineteen isolates were found to be multidrug-resistant by susceptibility testing. IS6110 typing showed that virtually all isolates were unique and therefore had independently acquired drug resistance. Seventy-nine percent of isoniazid-resistant strains had a Ser315Thr amino acid change in KatG. Ninety-five percent of rifampin-resistant isolates had amino acid replacements in the rifampin-resistance determining region of RpoB. Six of 11 ethambutol-resistant strains had EmbB alterations. Eleven pyrazinamide-resistant strains had distinct mutations in pncA.
  
  
  CONCLUSIONS
  Virtually all organisms evolved drug resistance independently. The types of drug resistance-associated mutations identified were very similar to changes occurring in isolates from other areas of the world. Nucleotide sequence-based strategies for rapid detection of drug resistance-conferring mutants will be applicable to organisms recovered in Peru, and potentially other areas of Latin America.
authors.affiliation: Institute for the Study of Human Bacterial Pathogenesis, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: P
authors.initials: P
authors.lastname: Escalante
authors.forename: S
authors.initials: S
authors.lastname: Ramaswamy
authors.forename: H
authors.initials: H
authors.lastname: Sanabria
authors.forename: H
authors.initials: H
authors.lastname: Soini
authors.forename: X
authors.initials: X
authors.lastname: Pan
authors.forename: O
authors.initials: O
authors.lastname: Valiente-Castillo
authors.forename: J M
authors.initials: JM
authors.lastname: Musser
mesh_terms: D000581:Amidohydrolases / Q000235:genetics; D001426:Bacterial Proteins; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II / Q000235:genetics; D012321:DNA-Directed RNA Polymerases; D018432:Drug Resistance, Multiple / Q000235:genetics*; D005798:Genes, Bacterial; D005838:Genotype; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D010430:Pentosyltransferases / Q000235:genetics; D010544:Peroxidases / Q000235:genetics; D010568:Peru; D010940:Plant Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D010940:Plant Proteins; C101305:RpoB protein, Oryza sativa; D010544:Peroxidases; C076136:catalase HPI; D010430:Pentosyltransferases; C101967:arabinosyltransferase; D012321:DNA-Directed RNA Polymerases; D000581:Amidohydrolases; C022490:pyrazinamide deamidase; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II