Maria Alice da Silva Telles

III Diretrizes para Tuberculose da Sociedade Brasileira de Pneumologia e Tisiologia

New scientific articles about tuberculosis (TB) are published daily worldwide. However, it is difficult for health care workers, overloaded with work, to stay abreast of the latest research findings and to discern which information can and should be used in their daily practice on assisting TB patients. The purpose of the III Brazilian Thoracic Association (BTA) Guidelines on TB is to critically review the most recent national and international scientific information on TB, presenting an updated text with the most current and useful tools against TB to health care workers in our country. The III BTA Guidelines on TB have been developed by the BTA Committee on TB and the TB Work Group, based on the text of the II BTA Guidelines on TB (2004). We reviewed the following databases: LILACS (SciELO) and PubMed (Medline). The level of evidence of the cited articles was determined, and 24 recommendations on TB have been evaluated, discussed by all of the members of the BTA Committee on TB and of the TB Work Group, and highlighted. The first version of the present Guidelines was posted on the BTA website and was available for public consultation for three weeks. Comments and critiques were evaluated. The level of scientific evidence of each reference was evaluated before its acceptance for use in the final text.

Mutations in katG, inhA, and ahpC Genes of Brazilian Isoniazid-Resistant Isolates of Mycobacterium tuberculosis

ABSTRACT The presence of mutations in specific regions of the katG, inhA, and ahpC genes was analyzed with 69 Mycobacterium tuberculosis isoniazid-resistant isolates from three Brazilian states. Point mutations in codon 315 of the katG gene were observed in 87.1, 60.9, and 60% of the isolates from Rio Grande do Sul, Rio de Janeiro, and São Paulo, respectively. Mutations in the inhA gene were identified only in one isolate from RJ State, and the ahpC promoter region revealed mutations in distinct positions in 12.9, 21.7, and 6.7% of the isolates from RS, RJ and SP, respectively.

Correlations of mutations in katG, oxyR-ahpC and inhA genes and in vitro susceptibility in Mycobacterium tuberculosis clinical strains segregated by spoligotype families from tuberculosis prevalent countries in South America.

BackgroundMutations 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.ResultsWe, 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.ConclusionOur 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.

Mycobacterium tuberculosis strains of the Beijing genotype are rarely observed in tuberculosis patients in South America

The frequency of the Beijing genotype of Mycobacterium tuberculosis as a cause of tuberculosis (TB) in South America was determined by analyzing genotypes of strains isolated from patients that had been diagnosed with the disease between 1997 and 2003 in seven countries of the subcontinent. In total, 19 of the 1,202 (1.6%) TB cases carried Beijing isolates, including 11 of the 185 patients from Peru (5.9%), five of the 512 patients from Argentina (1.0%), two of the 252 Brazilian cases (0.8%), one of the 166 patients from Paraguay (0.6%) and none of the samples obtained from Chile (35), Colombia (36) and Ecuador (16). Except for two patients that were East Asian immigrants, all cases with Beijing strains were native South Americans. No association was found between carrying a strain with the Beijing genotype and having drug or multi-drug resistant disease. Our data show that presently transmission of M. tuberculosis strains of the Beijing genotype is not frequent in Latin America. In addition, the lack of association of drug resistant TB and infection with M. tuberculosis of the Beijing genotype observed presently demands efforts to define better the contribution of the virulence and lack of response to treatment to the growing spread of Beijing strains observed in other parts of the world.

Human Mycobacterium bovis infection in ten Latin American countries.

The aim of this work was to obtain the best possible estimate of the relevance of bovine tuberculosis (BTB) in humans in Argentina, Brazil, Chile, Colombia, Costa Rica, Dominican Republic, Ecuador, Peru, Uruguay and Venezuela. Sources of information were a questionnaire filled by the participant laboratories, and a search of published literature (1970-2007). Only four of these countries reported bacteriologically confirmed cases of BTB in humans. Most of these were diagnosed in Argentina, where the mean percentage of Mycobacterium bovis cases in relation to those due to Mycobacterium tuberculosis (2000-2006) ranged from 0.34% to 1.0%, according to the region. A slowly decreasing trend was observed in non HIV as well as in HIV/AIDS patients in Buenos Aires. In most of these countries, the low coverage of culture methods, especially of those including pyruvate-containing media, appropriate to isolate M. bovis, contributes to an underestimate of the problem. It was confirmed that BTB in humans exists, even though its relevance seems to be low. Milk pasteurization, sanitary controls to dairy products, and meat inspection at slaughterhouses contribute to the protection of human health. However, occupational aerogenous exposure to TB cattle and their carcasses remains a source of infection in the region.

Characterization of pncA Mutations in Pyrazinamide-Resistant Mycobacterium tuberculosis in Brazil

ABSTRACT In this study the nucleotide sequence of the pncA gene from 59 Mycobacterium tuberculosis clinical isolates was analyzed. Mutations in the pncA gene were identified in 29 of 40 pyrazinamide-resistant isolates, and no pyrazinamidase activity was detected in 39 of them. Twelve mutations found in this work have not been described previously.

Molecular characterization of Mycobacterium kansasii isolates in the State of São Paulo between 1995-1998

Mycobacterium kansasii is the most common cause of pulmonary nontuberculous mycobacteria infection and classical identification of this pathogen needs a time consuming phenotypic tests. Polymerase chain reaction-restriction fragment length polymorphism analysis (PRA) of the gene enconding for the 65 kDa heat shock (hsp65) protein offers an easy, rapid, and inexpensive procedure to identify and subtype M. kansasii isolates. In the present study, we performed a retrospective analysis of patients who had mycobacteria identified on the basis of phenotypic tests by means of a review of database at Mycobacteria Laboratory of the Instituto Adolfo Lutz in the period 1995-1998. A total of 9381 clinical isolates were analyzed of which 7777 (82.9%) were identified as M. tuberculosis complex and 1604 (17.1%) as nontuberculous mycobacteria. Of the 296 M. kansasii isolates, 189 (63.8%) isolates obtained from 119 patients were viable and were analyzed by PRA-hsp65. Hundred eight two (98.9%) were classified as M. kansasii type I. Two isolates were classified as type II and III and five isolates were characterized as other Mycobacterium species. Clinical isolates of M. kansasii in the state of Sao Paulo was almost exclusively subtype I regardless of HIV status.

Standartization of broth microdilution method for Mycobacterium tuberculosis

Indirect drug susceptibility tests of Mycobacterium tuberculosis was done to investigate the accuracy and feasibility of a broth microdilution method (BMM) for determining minimal inhibitory concentrations of conventional drugs against M. tuberculosis. Test drugs included isoniazid (H), rifampicin (R), ethambutol (E), streptomycin (S) and pyrazinamide (Z). Fifty isolates of M. tuberculosis from patients who had never received drug therapy, and H37Rv strain for control, were evaluated in the system. When comparing this method with the gold standard proportional method in Lowenstein-Jensen medium, sensitivity of 100% for all drugs and specifities of 91, 100, 96, 98 and 85% were observed respectively for H, R, E, S and Z. The BMM was read faster (14-20 days) than the proportional method (20-28 days). The microdilution method evaluated allows the testing of multiple drugs in multiple concentrations. It is easy to perform and does not require special equipment or expensive supplies. In contrast to radiometric method it does not use radioactive material.

Cord formation and colony morphology for the presumptive identification of Mycobacterium tuberculosis complex

The identification of Mycobacterium tuberculosis complex (MT), using non-molecular methods, is time-consuming. The objective of this study was to evaluate a screening test for the presumptive identification of MT, which could potentially decrease laboratory turn-around time for reporting preliminary results. From January 1998 to December 1999, 3056 cultures were analysed at the Mycobacterial Laboratory, Instituto Adolfo Lutz, Sao Paulo, Brasil. The screening test consisted of observation of colony morphology on Lowenstein Jensen medium and evaluation of cord formation on smear microscopy from those positive cultures. After the screening test, the cultures identified as non-tuberculous mycobacteria were identified to species by conventional methods (growth on culture and biochemical tests). Those identified as MT were submitted to drug susceptibility tests. The presumptive identification of MT using the proposed screening test, when compared with conventional tests, presented 98.9, 86.9, 97.8 and 93.0% of sensitivity, specificity, positive and negative predictive values, respectively. The conclusion is that it is possible to make a presumptive identification of MT using visual analysis of colony morphology and cord formation on microscopy examination. This method could be used to report the presumptive identification of MT and to guide laboratory decisions regarding susceptibility and identification tests with little cost and in a very practical way.

Gargalos e recomendações para a incorporação de novas tecnologias na rede pública laboratorial de tuberculose no Brasil

The World Health Organization (WHO) has recently recommended new technologies for the diagnosis of tuberculosis. The WHO recommendations include the development of a strategic plan for bringing the network up to grade; investment in supervision and quality control; and implementation of a system of laboratory environmental management. Without those measures having been taken, no new technology can be effectively incorporated. We surveyed the tuberculosis laboratory network in Brazil in order to identify possible bottlenecks for the incorporation of new technologies. We identified a lack of resources allocated to supervision and quality control; a low number of requests for cultures; a lack of effective laboratory information systems; and a lack of awareness regarding the future infrastructure needs of the laboratory network at the municipal level.