Email updates

Keep up to date with the latest news and content from BMC Research Notes and BioMed Central.

Open Access Short Report

Characterization of the genetic diversity of Mycobacterium tuberculosis in São Paulo city, Brazil

Natália H Mendes1, Fernando AF Melo2, Adolfo CB Santos1, José RC Pandolfi1, Elisabete A Almeida2, Rosilene F Cardoso3, Henri Berghs4, Suzana David5, Faber K Johansen1, Lívia G Espanha1, Sergio RA Leite6 and Clarice QF Leite1*

Author Affiliations

1 Laboratory of Micobacteriology, Faculty of Pharmacy, São Paulo State University at Araraquara, UNESP. Araraquara-Jaú Road Km 01, Araraquara, SP, 14801-902, Brazil

2 Clemente Ferreira Institute. 717 Consolação St, São Paulo, SP, 01301-000, Brazil

3 State University of Maringá. 5790 Colombo Ave, Maringá, PR, 87020-900, Brazil

4 Fairport Ltda. 293 Jacarandá St, São Paulo, SP, 04926-160, Brazil

5 National Institute of Heath Dr. Ricardo Jorge. Padre Cruz Ave, Lisbon, 1649-016, Portugal

6 Institute of Chemistry, São Paulo State University at Araraquara, UNESP, 55 Prof. Francisco Degni St, Araraquara, SP, 14800-060, Brazil

For all author emails, please log on.

BMC Research Notes 2011, 4:269  doi:10.1186/1756-0500-4-269

Published: 29 July 2011

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).

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.