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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.

Abstract: In mycobacteria, the study of inhibition by metal ions has been limited by the absence of suitable molecular vectors. Recently, we reported on the inhibitory activity of a family of chelators, macrocyclic compounds (MCC), against Mycobacterium tuberculosis. In this study equimolar concentrations of the free cations vanadium(IV), arsenic(III), iron(III), indium(III) and bismuth(III), and as 1:1 complexes with the MCC 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetra-acetic acid (TETA) were tested in vitro against M. tuberculosis using the Bactec™ 460 TB radiometric technology (Becton-Dickinson, MD, USA). Radiometric inhibition above 80% was obtained with free indium(III) and bismuth(III), and ranged from 80% to 99%, with the complexes of TETA with vanadium(IV), bismuth(III) and indium(III), in the order of increasing activity. The highest radiometric inhibition levels were obtained with the [In(TETA)]− complex, which caused drops of up to 4log units in cellular viability. The minimal inhibitory concentration of this compound was evaluated at 3μM. [Copyright &y& Elsevier]

Subinhibitory concentrations of bacitracin, vancomycin and other inhibitors of cell wall synthesis reversed to varying extents the intrinsic resistance of Mycobacterium tuberculosis to clarithromycin. Ethambutol reversed clarithromycin resistance in all of the M. tuberculosis strains studied regardless of their susceptibility to this drug. [ABSTRACT FROM AUTHOR]

The present population study, from 1999 to 2003, has been based on the use of Spoligotyping in the genotyping of 452 isolates of the Mycobacterium tuberculosis complex from tuberculosis patients of the Fernando Fonseca Hospital. Spoligotypes were identified as "shared types" (STs) with the aid of an international database. Eleven rarely found STs, not identified in the database, grouped 8.4% of the isolates. Moreover, particular to Portugal, may be the predominance of STs identified in the database but not previously classified as genotypic families, such as ST244, ST150 and ST389, representing 13.3 % of the total. The identification of clinical isolates of M. africanum genotype Afri1 and of M. tuberculosis genotype CAS1 may confirm import of isolates of African and Asian origin. M. tuberculosis of the Beijing family was first reported by us as of 1999. Since then, the number of isolates at the Hospital has passed from one to five annually, representing 2.2% of the total and the tenth most predominant family in the present study. M. tuberculosis Beijing may correspond to an emerging problem in Portugal due to recent immigration from Eastern Europe and Asia. Other genotypes, ST150 and ST389, have shown increase, the significance of which is not clear. However, the relative frequencies of the predominant families LAM, T1 and Haarlem remained relatively stable. The present study confirms the genetic variability in Portugal of M. tuberculosis complex isolates. These studies may contribute to the definition of priorities in the national tuberculosis control programs.

Spoligotyping was used in the genotyping of 219 isolates of the Mycobacterium tuberculosis complex, from patients of the Hospital Fernando Fonseca. This technique, based on PCR methodology, analyses a region of the chromosome specific of the Mycobacterium tuberculosis complex, the DR locus (Direct Repeat). With the aid of an international database, we showed that the predominant Spoligotypes belonged to the LAM family (Latino-American Mediterranean), 29.2 %. The LAM 9 family, with 12.3 %, left us attentive to the possible import of the disease through populations from South America, were it has been frequently identified. The genotypic families T1 and Haarlem, with 6.4 % and 8.7 % respectively, represented a frequency typical to Europe. The Beijing family, with 1.4 %, may represent an emerging problem in our country due to recent immigration of Asian and Eastern European populations. Isolates with a Spoligotype of the M. bovis type were found at a high percentage, 3.7 %. In Europe, this infection is extremely rare suggesting the result may not be due to M. bovis infection but to M. bovis BCG (due to vaccination or eventual recombinant BCG based therapies), or M. africanum (due to the proximity of the two species). A high percentage of the Spoligotypes were not identified by the database, 21.4 %. This is the first study of this type amongst us and may be the starting point for the creation of a data base with important consequences on the national program against tuberculosis.