title: Molecular characterization of multidrug-resistant Mycobacterium tuberculosis isolates from high prevalence tuberculosis states in Mexico.
abstract: Mexico is one of the most important contributors of multidrug resistance tuberculosis (MDR-TB) in Latin-America, however little is known about the molecular characteristics of these strains. For this reason, the objective of this work was to determine the genotype and characterize polymorphisms in genes associated with resistance to rifampicin, isoniazid, and second-line drugs in isolates from two regions of Mexico with high prevalence of drug resistant tuberculosis. Clinical isolates from individuals with confirmed MDR-TB were genotyped using MIRU-VNTR 12 loci. To characterize the polymorphisms in genes associated with resistance to rifampicin, isoniazid and second-line drugs; rpoB, katG, inhA, rrs, eis, gyrA, gyrB and tlyA were sequenced. 22 (41%) of the 54 MDR-TB isolates recovered were from the state of Baja California, while 32 (59%) were from Veracruz. The results show the katGS315T mutation was observed in 20% (11/54) of the isolates, while rpoBS315L was present in 33% (18/54). rrs had three polymorphisms (T1239C, ntA1401C and ntA1401G), gyrB presented no modifications, whereas gyrA showed five (S95T, F60Y, A90V, S91P and P124A), eis two (G-10A and A431G) and tlyA one (insertion at codon 67). Only 20% (11/54) of isolates were confirmed as MDR-TB by sequencing, and no mutations at any of the genes sequenced were observed in 43% (23/54) of the strains. Two isolates were recognized with the proper set of mutations like pre-XDR and one was XDR-TB. Eighteen isolates were classified as orphans and the remaining thirty-six were distributed in fourteen lineages, the most frequent were S (11%), Haarlem (9%), Ghana (9%) and LAM (7%). Out of the fourteen clusters identified, seven included unknown genotypes and nine had lineages. This is one of the most detailed analyses of genotypic characteristics and mutations associated with drug resistance to first and second-line drugs in MDR-TB isolates from Mexico. An important genetic variability and significant discrepancy between phenotypic tests and polymorphisms was observed. Our results set the need to screen additional loci as well as implement a molecular epidemiological surveillance system of MDR-TB in the country.
authors.affiliation: Instituto de Salud Pública, Universidad Veracruzana, Av. Luis Castelazo Ayala s/n, Col. Industrial Animas, CP 91190 Jalapa, Veracruz, Mexico.
authors.forename: Dulce Maria
authors.initials: DM
authors.lastname: Juarez-Eusebio
authors.affiliation: Instituto de Salud Pública, Universidad Veracruzana, Av. Luis Castelazo Ayala s/n, Col. Industrial Animas, CP 91190 Jalapa, Veracruz, Mexico; Instituto de Ciencias de Salud, Universidad Veracruzana, Veracruz, Mexico.
authors.forename: Daniela
authors.initials: D
authors.lastname: Munro-Rojas
authors.affiliation: Laboratorio de Epidemiología y Ecología y Molecular, Escuela de Ciencias de la Salud, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico; Red Multidisciplinaria de Investigación en Tuberculosis (www.remitb.org), Mexico.
authors.forename: Raquel
authors.initials: R
authors.lastname: Muñiz-Salazar
authors.affiliation: Clínica de Tuberculosis, Hospital General de Tijuana, ISESALUD, Tijuana, Baja California, Mexico; Facultad de Medicina y Psicología, Universidad Autónoma de Baja California, Baja California, Mexico; Red Multidisciplinaria de Investigación en Tuberculosis (www.remitb.org), Mexico.
authors.forename: Rafael
authors.initials: R
authors.lastname: Laniado-Laborín
authors.affiliation: Red Multidisciplinaria de Investigación en Tuberculosis (www.remitb.org), Mexico; Departamento de Mycobacterias, Instituto Nacional de Diagnóstico y Referencia Epidemiológica, Mexico.
authors.forename: Jose Armando
authors.initials: JA
authors.lastname: Martinez-Guarneros
authors.affiliation: Facultad de Ciencias, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico; Red Multidisciplinaria de Investigación en Tuberculosis (www.remitb.org), Mexico.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Flores-López
authors.affiliation: Instituto de Salud Pública, Universidad Veracruzana, Av. Luis Castelazo Ayala s/n, Col. Industrial Animas, CP 91190 Jalapa, Veracruz, Mexico; Red Multidisciplinaria de Investigación en Tuberculosis (www.remitb.org), Mexico. Electronic address: robzencue@gmail.com.
authors.forename: Roberto
authors.initials: R
authors.lastname: Zenteno-Cuevas
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D016000:Cluster Analysis; D054908:Extensively Drug-Resistant Tuberculosis / Q000453:epidemiology / Q000382:microbiology; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008800:Mexico / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D018598:Minisatellite Repeats; D058885:Multilocus Sequence Typing; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics*; D015995:Prevalence; D018088:Tuberculosis, Multidrug-Resistant / Q000453:epidemiology* / Q000382:microbiology*
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins
keywords: Baja California; Multidrug resistance; Tuberculosis; Veracruz