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Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:25:57Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:47:17Z : No. of bitstreams: 1 2-s2.0-79960881158.pdf: 269242 bytes, checksum: dac50b17746f5739edcbadf223e062e4 (MD5) Made available in DSpace on 2014-05-27T11:25:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-02 Background: Tuberculosis is a major health problem in São Paulo, Brazil, which is the most populous and one of the most cosmopolitan cities in South America. To characterize the genetic diversity of Mycobacterium tuberculosis in the population of this city, the genotyping techniques of spoligotyping and MIRU were applied to 93 isolates collected in two consecutive years from 93 different tuberculosis patients residing in São Paulo city and attending the Clemente Ferreira Institute (the reference clinic for the treatment of tuberculosis). Findings. Spoligotyping generated 53 different spoligotype patterns. Fifty-one isolates (54.8%) were grouped into 13 spoligotyping clusters. Seventy- two strains (77.4%) showed spoligotypes described in the international databases (SpolDB4, SITVIT), and 21 (22.6%) showed unidentified patterns. The most frequent spoligotype families were Latin American Mediterranean (LAM) (26 isolates), followed by the T family (24 isolates) and Haarlem (H) (11 isolates), which together accounted for 65.4% of all the isolates. These three families represent the major genotypes found in Africa, Central America, South America and Europe. Six Spoligo-International- types (designated SITs by the database) comprised 51.8% (37/72) of all the identified spoligotypes (SIT53, SIT50, SIT42, SIT60, SIT17 and SIT1). Other SITs found in this study indicated the great genetic diversity of M. tuberculosis, reflecting the remarkable ethnic diversity of São Paulo city inhabitants. The MIRU technique was more discriminatory and did not identify any genetic clusters with 100% similarity among the 93 isolates. The allelic analysis showed that MIRU loci 26, 40, 23 and 10 were the most discriminatory. When MIRU and spoligotyping techniques were combined, all isolates grouped in the 13 spoligotyping clusters were separated. Conclusions: Our data indicated the genomic stability of over 50% of spoligotypes identified in São Paulo and the great genetic diversity of M. tuberculosis isolates in the remaining SITs, reflecting the large ethnic mix of the São Paulo city inhabitants. The results also indicated that in this city, M. tuberculosis isolates acquired drug resistance independently of genotype and that resistance was more dependent on the selective pressure of treatment failure and the environmental circumstances of patients. © 2011 Leite et al; licensee BioMed Central Ltd. Laboratory of Micobacteriology Faculty of Pharmacy São Paulo State University at Araraquara, Araraquara-Jaú Road Km 01, Araraquara, SP 14801-902 Clemente Ferreira Institute, 717 Consolação St, São Paulo, SP 01301-000 State University of Maringá, 5790 Colombo Ave, Maringá, PR 87020-900 Fairport Ltda, 293 Jacarandá St, São Paulo, SP 04926-160 National Institute of Heath Dr. Ricardo Jorge, Padre Cruz Ave, Lisbon 1649-016 Institute of Chemistry São Paulo State University at Araraquara UNESP, 55 Prof. Francisco Degni St., Araraquara, SP 14800-060 Laboratory of Micobacteriology Faculty of Pharmacy São Paulo State University at Araraquara, Araraquara-Jaú Road Km 01, Araraquara, SP 14801-902 Institute of Chemistry São Paulo State University at Araraquara UNESP, 55 Prof. Francisco Degni St., Araraquara, SP 14800-060