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Tuberculosis Research and Treatment
Volume 2011, Article ID 239042, 9 pages
Research Article

Mycobacterium tuberculosis Complex Genotype Diversity and Drug Resistance Profiles in a Pediatric Population in Mexico

1Department of Infectious Diseases, Instituto Nacional de Pediatría, Mexico City, Mexico
2Instituto Mexicano del Seguro Social Foundation, Mexico City, Mexico
3Subdivision of Medical Research, Instituto Nacional de Pediatría, Mexico City, DF, Mexico
4Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
5Department of Micobacteriology, Instituto De Diagnóstico y Referencia de Epidemiológicos, Secretaria de Salud, Mexico City, Mexico
6WHO Supranational Tuberculosis Reference Laboratory, Institut Pasteur de la Guadeloupe, Abymes, France

Received 17 March 2011; Accepted 22 May 2011

Academic Editor: Prasit Palittapongarnpim

Copyright © 2011 Mercedes Macías Parra et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The aim of this study was to determine the frequency of drug resistance and the clonality of genotype patterns in M. tuberculosis clinical isolates from pediatric patients in Mexico ( patients from 19 states; time period—January 2002 to December 2003). Pulmonary disease was the most frequent clinical manifestation (71%). Children with systemic tuberculosis (TB) were significantly younger compared to patients with localized TB infections (mean years versus years ). Resistance to any anti-TB drug was detected in 24/90 (26.7%) of the isolates; 21/90 (23.3%) and 10/90 (11.1%) were resistant to Isoniazid and Rifampicin, respectively, and 10/90 (11.1%) strains were multidrug-resistant (MDR). Spoligotyping produced a total of 55 different patterns; 12/55 corresponded to clustered isolates ( , clustering rate of 52.2%), and 43/55 to unclustered isolates (19 patterns were designated as orphan by the SITVIT2 database). Database comparison led to designation of 36 shared types (SITs); 32 SITs ( isolates) matched a preexisting shared type in SITVIT2, whereas 4 SITs ( isolates) were newly created. Lineage classification based on principal genetic groups (PGG) revealed that 10% of the strains belonged to PGG1 (Bovis and Manu lineages). Among PGG2/3 group, the most predominant clade was the Latin-American and Mediterranean (LAM) in 27.8% of isolates, followed by Haarlem and T lineages. The number of single drug-resistant (DR) and multidrug-resistant (MDR-TB) isolates in this study was similar to previously reported in studies from adult population with risk factors. No association between the spoligotype, age, region, or resistance pattern was observed. However, contrary to a study on M. tuberculosis spoligotyping in Acapulco city that characterized a single cluster of SIT19 corresponding to the EAI2-Manila lineage in 70 (26%) of patients, not a single SIT19 isolate was found in our pediatric patient population. Neither did we find any shared type belonging to the EAI family which represents ancestral PGG1 strains within the M. tuberculosis complex. We conclude that the population structure of pediatric TB in our setting is different from the one prevailing in adult TB patient population of Guerrero.