Background: Mutations associated with resistance to rifampin or streptomycin have been reported for W/Beijing and Latin American Mediterranean (LAM) strain families of Mycobacterium tuberculosis. A few studies with limited sample sizes have separately evaluated mutations in katG, ahpC and inhA genes that are associated with isoniazid (INH) resistance. Increasing prevalence of INH resistance, especially in high tuberculosis (TB) prevalent countries is worsening the burden of TB control programs, since similar transmission rates are noted for INH susceptible and resistant M. tuberculosis strains. Results: We, therefore, conducted a comprehensive evaluation of INH resistant M. tuberculosis strains (n = 224) from three South American countries with high burden of drug resistant TB to characterize mutations in katG, ahpC and inhA gene loci and correlate with minimal inhibitory concentrations (MIC) levels and spoligotype strain family. Mutations in katG were observed in 181 (80.8%) of the isolates of which 178 (98.3%) was contributed by the katG S315T mutation. Additional mutations seen included oxyR-ahpC; inhA regulatory region and inhA structural gene. The S315T katG mutation was significantly more likely to be associated with MIC for INH ≥2 μg/mL. The S315T katG mutation was also more frequent in Haarlem family strains than LAM (n = 81) and T strain families. Conclusion: Our data suggests that genetic screening for the S315T katG mutation may provide rapid information for anti-TB regimen selection, epidemiological monitoring of INH resistance and, possibly, to track transmission of INH resistant strains.

Background: Developments in molecular detection and strain differentiation of members of Mycobacterium tuberculosis complex have proved to be useful. The DNA extraction method influences the amplification efficiency, causing interference on the sensitivity and respective inhibitors. The aim of this study was to standardize a simple and fast DNA extraction method, providing DNA amplification by IS6110-PCR effectively free from undue interferences. Findings: The efficiency of the six different protocols tested in M. tuberculosis cultures has varied from 75% to 92.5%. This preliminary study evaluating the IS6110 PCR sensitivity and specificity was developed in DNA extracted from microscope slides, and achieved 100% of efficiency. Conclusions: DNA extraction by Chelex + NP-40 method from both, cultures of M. tuberculosis and smear slides, resulted in good quantity of interference free DNA, especially in samples with low concentrations of genetic material; therefore, such technique may be used for the molecular diagnosis of tuberculosis.

Early, accurate diagnosis of tuberculosis is one of the major pillars of the control of the disease. The purpose of this consensus statement is to provide health professionals with the most current, useful evidence for the diagnosis of tuberculosis in Brazil. To that end, the Tuberculosis Committee of the Brazilian Thoracic Association brought together 14 members of the Association with recognized expertise in tuberculosis in Brazil to compose the statement. A nonsystematic review of the following topics was carried out: clinical diagnosis, bacteriological diagnosis, radiological diagnosis, histopathological diagnosis, diagnosis of tuberculosis in children, and diagnosis of latent tuberculosis infection.

OBJETIVO: Descrever os dados de função pulmonar de pacientes com seqüela de tuberculose pulmonar, pleural e pleuropulmonar. MÉTODOS: Em um ambulatório de tuberculose de um hospital universitário, de 218 pacientes atendidos, 56 tinham seqüela de tuberculose pulmonar, pleural e pleuropulmonar, e 162 tiveram outros tipos de tuberculose. No laboratório de função pulmonar, 43 foram elegíveis para o estudo, de fevereiro de 2000 a julho de 2004. Foram excluídos os pacientes com doenças prévias, como: asma; doença pulmonar obstrutiva crônica; insuficiência cardíaca; doenças do colágeno; silicose; cirurgia torácica prévia; e espirometria inaceitável ou não realizada. Os campos pulmonares foram divididos em seis zonas e os radiogramas classificados em: grau I, com mínimo envolvimento em somente uma zona sem cavitação; grau II, com envolvimento de duas ou três zonas ou uma zona com cavitação; grau III, com envolvimento grave em mais de três zonas com ou sem cavitação. RESULTADOS: Cinqüenta pacientes foram incluídos no estudo e 44 deles tiveram tuberculose pulmonar (88%). O distúrbio ventilatório combinado foi o mais prevalente, 17/50 (34%). Os distúrbios acentuados foram mais significativos no grau III (p = 0,0002). A função pulmonar normal predominou nos graus I e II (p = 0,002). CONCLUSÃO: A descoberta e o tratamento precoce dos casos de tuberculose pulmonar contribuem para a diminuição dos casos da doença e de suas seqüelas, melhorando a qualidade de vida desses pacientes. Os autores sugerem uma análise logitudinal e seqüencial (protocolo), com maior número de pacientes com seqüelas de tuberculose nos serviços de referência no Brasil.

Historically, all efforts against tuberculosis were focused on rapid diagnosis and effective treatment to break the chain of transmission of Mycobacterium tuberculosis. However, in the last few years, more and more evidence has been found on the dramatic consequences of the condition defined as post-tuberculosis lung disease (PTLD). Approximately one third of patients surviving pulmonary tuberculosis face considerable ongoing morbidities, including respiratory impairment, psychosocial challenges, and reduced health-related quality of life after treatment completion. Given the important global and local burden of tuberculosis, as well as the estimated burden of PTLD, the development of a consensus document by a Brazilian scientific society-Sociedade Brasileira de Pneumologia e Tisiologia (SBPT)-was considered urgent for the prevention and management of this condition in order to allocate resources to and within tuberculosis services appropriately and serve as a guide for health care professionals. A team of eleven pulmonologists and one methodologist was created by the SBPT to review the current evidence on PTLD and develop recommendations adapted to the Brazilian context. The expert panel selected the topics on the basis of current evidence and international guidelines. During the first phase, three panel members drafted the recommendations, which were divided into three sections: definition and prevalence of PTLD, assessment of PTLD, and management of PTLD. In the second phase, all panel members reviewed, discussed, and revised the recommendations until a consensus was reached. The document was formally approved by the SBPT in a special session organized during the 2023 SBPT Annual Conference.

We aimed to characterize the genetic diversity of drug-resistant Mycobacterium tuberculosis (MTb) clinical isolates and investigate the molecular epidemiology of multidrug-resistant (MDR) tuberculosis from Minas Gerais State, Brazil. One hundred and four MTb clinical isolates were assessed by IS6110-RFLP, 24-locus mycobacterial interspersed repetitive units variable-number tandem repeats (MIRU-VNTR), TB-SPRINT (simultaneous spoligotyping and rifampicin-isoniazid drug-resistance mutation analysis) and 3R-SNP-typing (analysis of single-nucleotide polymorphisms in the genes involved in replication, recombination and repair functions). Fifty-seven different IS6110-RFLP patterns were found, among which 50 had unique patterns and 17 were grouped into seven clusters. The discriminatory index (Hunter and Gaston, HGDI) for RFLP was 0.9937. Ninety-nine different MIRU-VNTR patterns were found, 95 of which had unique patterns and nine isolates were grouped into four clusters. The major allelic diversity index in the MIRU-VNTR loci ranged from 0.6568 to 0.7789. The global HGDI for MIRU-VNTR was 0.9991. Thirty-two different spoligotyping profiles were found: 16 unique patterns (n = 16) and 16 clustered profiles (n = 88). The HGDI for spoligotyping was 0.9009. The spoligotyped clinical isolates were phylogenetically classified into Latin-American Mediterranean (66.34 %), T (14.42 %), Haarlem (5.76 %), X (1.92 %), S (1.92 %) and U (unknown profile; 8.65 %). Among the U isolates, 77.8 % were classified further by 3R-SNP-typing as 44.5 % Haarlem and 33.3 % LAM, while the 22.2 % remaining were not classified. Among the 104 clinical isolates, 86 were identified by TB-SPRINT as MDR, 12 were resistant to rifampicin only, one was resistant to isoniazid only, three were susceptible to both drugs, and two were not successfully amplified by PCR. A total of 42, 28 and eight isolates had mutations in rpoB positions 531, 526 and 516, respectively. Correlating the cluster analysis with the patient data did not suggest recent transmission of MDR-TB. Although our results do not suggest strong transmission of MDR-TB in Minas Gerais (using a classical 100 % MDR-TB identical isolates cluster definition), use of a smoother cluster definition (>85 % similarity) does not allow us to fully eliminate this possibility; hence, around 20–30 % of the isolates we analyzed might be MDR-TB transmission cases.