title: Characterization of the genetic diversity of Mycobacterium tuberculosis in São Paulo city, Brazil.
abstract: 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).
  
  
  RESULTS
  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.
authors.affiliation: Laboratory of Micobacteriology, Faculty of Pharmacy, São Paulo State University at Araraquara, UNESP, Araraquara-Jaú Road Km 01, Araraquara, SP, 14801-902, Brazil. leitecqf@fcfar.unesp.br.
authors.forename: Natália H
authors.initials: NH
authors.lastname: Mendes
authors.forename: Fernando Af
authors.initials: FA
authors.lastname: Melo
authors.forename: Adolfo Cb
authors.initials: AC
authors.lastname: Santos
authors.forename: José Rc
authors.initials: JR
authors.lastname: Pandolfi
authors.forename: Elisabete A
authors.initials: EA
authors.lastname: Almeida
authors.forename: Rosilene F
authors.initials: RF
authors.lastname: Cardoso
authors.forename: Henri
authors.initials: H
authors.lastname: Berghs
authors.forename: Suzana
authors.initials: S
authors.lastname: David
authors.forename: Faber K
authors.initials: FK
authors.lastname: Johansen
authors.forename: Lívia G
authors.initials: LG
authors.lastname: Espanha
authors.forename: Sergio Ra
authors.initials: SR
authors.lastname: Leite
authors.forename: Clarice Qf
authors.initials: CQ
authors.lastname: Leite