Objective: To discuss the main aspects of co-infection with Mycobacterium tuberculosis and human immunodeficiency virus in the city of Taubaté (located in the state of São Paulo, Brazil) in 2001 and 2002. Methods: This study presents epidemiological data on tuberculosis cases occurring in Taubaté in 2001 and 2002. Results: Of the 250 cases of tuberculosis analyzed, 70 (28%) presented human immunodeficiency virus seropositivity, 95 (38%) presented human immunodeficiency virus seronegativity, and 85 (34%) were patients who had not been submitted to serological testing. In the first group (tuberculosis and human immunodeficiency virus seropositivity), males from 30 to 40 years of age predominated, the most common clinical presentation of tuberculosis was pulmonary (65.71%), and the cure rate was 59.38%. In the group of tuberculosis patients presenting human immunodeficiency virus seronegativity, males from 30 to 40 years of age also predominated, the most common clinical presentation of tuberculosis was also pulmonary (70.55%), and the cure rate was 81.63%. Conclusion: We conclude that the human immunodeficiency virus plays an important role in the epidemiology of tuberculosis. Therefore, serological testing for human immunodeficiency virus should be carried out when a diagnosis of tuberculosis is made.

Keywords: Tuberculosis/epidemiology; HIV infections; HIV; Prevalence

Background: Surveys of patients diagnosed with mycobacteriosis, taken at the Laboratory of Mycobacteriology of the Hospital das Clínicas da Universidade Federal de Minas Gerais, have shown that lack of information concerning diagnosis prevented 42% from initiating treatment. Objective: To evaluate the profile of patients with mycobacterial infection attending the Hospital das Clínicas da Universidade Federal de Minas Gerais. To describe the follow up of those patients and compare it to the guidelines made by the National Program for the Control of Tuberculosis. Methods: The files of patients diagnosed with mycobacterium infection during 2002 were selected from the archives of the Laboratory of Mycobacteriology of the Hospital das Clínicas da Universidade Federal de Minas Gerais. An active search for these patients was carried out and follow-up exams were then performed. Results: Of the 66 patients selected, 62 (94%) were positive for Mycobacterium tuberculosis and 4 (6%) had nontuberculous mycobacteriosis. Another 4 (6%) had been transferred to other institutions. Of the remaining 58, 37 (63%) had been cured, 1 (2%) had refused treatment, 9 (16%) were not found and 11 (19%) had died. Of the 11 deaths, 7 (64%) had tested positive for HIV. Conclusion: Patients failed to receive treatment not due to lack of diagnosis, but to inadequate structure, low awareness levels of all parties, and lack of tuberculosis control organization at the hospital level. Due to the high number of HIV-positive patients, the number of patients cured was lower than that required by the National Health Ministry. Deaths were attributed to HIV infection and lack of knowledge about the disease. In order to identify and address the problems associated with clinical laboratory practice, laboratory professionals must work in concert with their clinical counterparts when carrying out operational research on tuberculosis.

Keywords: Tuberculosis/diagnosis. Mycobacterium infections/complications.

We report the case of a 74-year-old male patient with a one-year history of chest pain in the suprasternal notch associated with erythema, edema and drainage of purulent material from a fistulous lesion. The patient was HIV-negative with no history of TB. A CT scan of the chest showed an osteolytic lesion in the sternum, and a biopsy revealed caseous granuloma, which, in the microbiological evaluation, was negative for fungi and acid-fast bacilli. The diagnosis of sternal osteomyelitis caused by Mycobacterium tuberculosis was confirmed using PCR.

Keywords: Thorax; Mycobacterium infections; Tuberculosis, osteoarticular; Sternum; Diagnosis.

Objective: To determine the drug resistance profile of Mycobacterium tuberculosis in Mozambique. Methods: We analyzed secondary data from the National Tuberculosis Referral Laboratory, in the city of Maputo, Mozambique, and from the Beira Regional Tuberculosis Referral Laboratory, in the city of Beira, Mozambique. The data were based on culture-positive samples submitted to first-line drug susceptibility testing (DST) between January and December of 2011. We attempted to determine whether the frequency of DST positivity was associated with patient type or provenance. Results: During the study period, 641 strains were isolated in culture and submitted to DST. We found that 374 (58.3%) were resistant to at least one antituberculosis drug and 280 (43.7%) were resistant to multiple antituberculosis drugs. Of the 280 multidrug-resistant tuberculosis cases, 184 (65.7%) were in previously treated patients, most of whom were from southern Mozambique. Two (0.71%) of the cases of multidrug-resistant tuberculosis were confirmed to be cases of extensively drug-resistant tuberculosis. Multidrug-resistant tuberculosis was most common in males, particularly those in the 21-40 year age bracket. Conclusions: M. tuberculosis resistance to antituberculosis drugs is high in Mozambique, especially in previously treated patients. The frequency of M. tuberculosis strains that were resistant to isoniazid, rifampin, and streptomycin in combination was found to be high, particularly in samples from previously treated patients.

Keywords: Extensively drug-resistant tuberculosis; Tuberculosis; Tuberculosis, multidrug-resistant.

Objective: To estimate the prevalence of latent Mycobacterium tuberculosis infection (LTBI) in renal transplant recipients and to assess sociodemographic, behavioral, and clinical associations with positive tuberculin skin test (TST) results. Methods: This was a cross-sectional study of patients aged ≥ 18 years who underwent renal transplantation at the Renal Transplant Center of the Federal University of Minas Gerais Hospital das Clínicas, located in the city of Belo Horizonte, Brazil. We included renal transplant recipients who underwent the TST between January 2011 and July 2013. If the result of the first TST was negative, a second TST was administered. Bivariate and multivariate analyses using logistic regression were used to determine factors associated with positive TST results. Results: The sample included 216 patients. The prevalence of LTBI was 18.5%. In the multivariate analysis, history of contact with a tuberculosis case and preserved graft function (estimated glomerular filtration rate ≥ 60 mL/min/1.73 m2) were associated with positive TST results. TST induration increased by 5.8% from the first to the second test, which was considered significant (p = 0.012). Conclusions: The prevalence of LTBI was low in this sample of renal transplant recipients. The TST should be administered if renal graft function is preserved. A second TST should be administered if the first TST is negative.

Keywords: Tuberculosis; Tuberculin test; Immunocompromised host.

Objective: To determine the prevalence of and the factors associated with latent Mycobacterium tuberculosis infection (LTBI) in prisoners in the state of Minas Gerais, Brazil. Methods: This was a cross-sectional cohort study conducted in two prisons in Minas Gerais. Tuberculin skin tests were performed in the individuals who agreed to participate in the study. Results: A total of 1,120 individuals were selected for inclusion in this study. The prevalence of LTBI was 25.2%. In the multivariate analysis, LTBI was associated with self-reported contact with active tuberculosis patients within prisons (adjusted OR = 1.51; 95% CI: 1.05-2.18) and use of inhaled drugs (adjusted OR = 1.48; 95% CI: 1.03-2.13). Respiratory symptoms were identified in 131 (11.7%) of the participants. Serological testing for HIV was performed in 940 (83.9%) of the participants, and the result was positive in 5 (0.5%). Two cases of active tuberculosis were identified during the study period. Conclusions: Within the prisons under study, the prevalence of LTBI was high. In addition, LTBI was associated with self-reported contact with active tuberculosis patients and with the use of inhaled drugs. Our findings demonstrate that it is necessary to improve the conditions in prisons, as well as to introduce strategies, such as chest X-ray screening, in order to detect tuberculosis cases and, consequently, reduce M. tuberculosis infection within the prison system.

Keywords: Prisons; Tuberculin test; Latent tuberculosis, HIV.

Objective: To evaluate tuberculin test results and relate them to the presence or absence of active tuberculosis, as well as to CD4+ and CD8+ T-lymphocyte counts. Method: The charts of 802 patients with acquired immunodeficiency syndrome treated between August of 1985 and March of 2003 were reviewed. Of the 185 patients submitted to tuberculin tests (23.1%), 107 (57.8%) were male, and 78 (42.2%) were female. Patients were divided into two study groups: tuberculin test reactors (n = 28); and tuberculin test non-reactors (n = 157). Among the reactors, the mean age was 30.60 years, with a standard deviation of 6.62 years, compared with 34.45 years, with a standard deviation of 10.32 years, among the non-reactors. Results: Most of the individuals tested presented only a mild response to the tuberculin test. We found that, at the time of the test, the percentage of individuals with active tuberculosis was greater in the reactor group than in the non-reactor group. During the test period, 10 reactor group patients and 11 non-reactor group patients presented some clinical form of active tuberculosis. In addition, CD4+ T-lymphocyte counts were lower than 200 cells/mm3 in 6 reactor group patients and in 8 non-reactor group patients. Conclusion: Indurations greater than 5 mm were unrelated to higher absolute CD4+ T-cell counts.

Keywords: Tuberculin test; Acquired immunodeficiency syndrome; Tuberculosis; CD4-positive T-lymphocytes; CD8-positive T-lymphocytes

Objective: To estimate the prevalence of human immunodeficiency virus seropositivity among patients with active tuberculosis residing in the city of Londrina, in the state of Paraná, Brazil and treated at the Pulmonology Clinic of the 17th Regional Health Facility of the State of Paraná, and to compare those coinfected with human immunodeficiency virus to those with active tuberculosis only in terms of the clinical form of tuberculosis, sputum smear microscopy, chest X-ray and tuberculosis treatment regimen. Methods: A transversal study involving 188 active tuberculosis patients was conducted. Tuberculosis and human immunodeficiency virus infection were diagnosed based on criteria established by the Brazilian Ministry of Health. In addition to the data obtained through individual tuberculosis investigation files, clinical and epidemiological information were collected by means of questionnaires, which were completed by all participating patients. Results: The prevalence of human immunodeficiency virus seropositivity among patients with tuberculosis was 14.9%. The rate of positive sputum microscopy results was higher in the tuberculosis-only group (p = 0.0275), and the ratio for patients treatment with alternative scheme was significantly higher in the co-infected group (p = 0.042). In 32.1% of the coinfected patients, the serological diagnosis of human immunodeficiency virus infection was made simultaneously to or following that of the tuberculosis. Conclusion: The results underscore the importance of routinely testing for human immunodeficiency virus antibodies in patients diagnosed with tuberculosis.

Keywords: Tuberculosis/complications; Tuberculosis/diagnosis; Soropositivity; HIV/immunology; HIV infections/complications; HIV infections/epidemiology; HIV infections/ drug therapy; Rifampin/therapeutic use; Disease progression

Objective: In view of the relevance of co-infection with tuberculosis and human immunodeficiency virus, this study was designed to determine tuberculosis prevalence and identify factors related to tuberculosis in patients residing in a region in which both infections are highly prevalent. Methods: All patients treated during 1999 at the HIV/AIDS Clinic of the Universidade Federal do Rio Grande (Rio Grande Federal University) University Hospital were evaluated retrospectively, from the time of human immunodeficiency virus diagnosis, in terms of the incidence of tuberculosis and its relationship to sociodemographic, behavioral and immunological factors. Results: The sample included 204 patients, and tuberculosis prevalence was found to be 27%. The multivariate analysis showed a significant correlation between the development of tuberculosis and being of African descent (odds ratio: 4.76; 95% confidence interval: 1.93-11.72) and an inverse correlation between the development of tuberculosis and the TCD4+ lymphocyte count at the time of human immunodeficiency virus diagnosis (odds ratio: 0.995; 95% confidence interval: 0.993-0.997). When analyzed separately, other variables were found to be potential risk factors: being of the male gender (odds ratio: 2.49; 95% confidence interval: 1.15-5.39); and using illicit drugs (odds ratio: 2.1; 95% confidence interval: 1.02-4.31). Conclusion: The factors responsible for the development of tuberculosis among patients who are human immunodeficiency virus seropositive include immunological, socioeconomic and demographic factors. The high rate of tuberculosis prevalence among the seropositive patients underscores the urgent need to implement strategies that combine rapid identification and prompt treatment of individuals with active or latent infection, as well as of those with whom they have been in contact.

Keywords: HIV Infections/complications; AIDS-related opportunistic infections/complications; Tuberculosis/etiology; Tuberculosis/epidemiology

Objective: Virulent strains of the Mycobacterium tuberculosis complex, under certain appropriate conditions, grow as characteristic ropes, bundles or serpentine cords known as cord factor or growth in cords. The objective of the present study was to evaluate cord factor detection as a method of achieving presumptive identification of the M. tuberculosis complex, comparing it to conventional typing tests. Methods: A total of 743 strains were analyzed from January of 2002 to December of 2005 in the Mycobacteria Sector of the Adolfo Lutz Institute, located in the city of Santos, Brazil. Samples were obtained from clinical specimens collected from patients with respiratory symptoms treated at basic health clinics in the greater metropolitan area of Santos. Ziehl-Neelsen-stained smears were prepared, 301 (40.5%) in MB/BacT broth and 442 (59.5%) on solid media, either Lowenstein-Jensen or Ogawa-Kudoh. Results: The sensitivity, specificity, positive predictive value and negative predictive value obtained during the performance comparison of the two methods (cord factor detection and conventional typing) using both isolation media were, respectively, 98.5, 88, 97 and 93%. The method was more sensitive on solid medium (100%), and the difference in sensitivity between the two media types was only 2.7%. Conclusions: Taking into consideration the results obtained, we conclude that, in laboratories with a high incidence of M. tuberculosis complex isolation and limited economic resources, cord factor detection is a fast and valid criterion for identifying these mycobacteria using liquid or solid medium. It also enables subsequent conclusive identification tests, as well as additional sensitivity tests when necessary.

Keywords: Laboratory techniques and procedures; Mycobacterium tuberculosis; Cord factors

Objective: To analyze and compare the mutations in two different regions of the katG gene, which is responsible for isoniazid (INH) resistance. Methods: We analyzed 97 multidrug-resistant Mycobacterium tuberculosis strains isolated in cultures of sputum samples obtained from the Professor Hélio Fraga Referral Center, in Brasília, Brazil. Another 6 INH-sensitive strains did not present mutations and were included as controls. We used PCR to amplify two regions of the katG gene (GenBank accession no. U06258)-region 1, (from codon 1 to codon 119) and region 2 (from codon 267 to codon 504)-which were then sequenced in order to identify mutations. Results: Seven strains were resistant to INH and did not contain mutations in either region. Thirty strains carried mutations in region 1, which was characterized by a high number of deletions, especially at codon 4 (24 strains). Region 2 carried 83 point mutations, especially at codon 315, and there was a serine-to-threonine (AGC-to-ACC) substitution in 73 of those cases. The analysis of region 2 allowed INH resistance to be diagnosed in 81.4% of the strains. Nine strains had mutations exclusively in region 1, which allowed the proportion of INH-resistant strains identified to be increased to 90.6%. Conclusions: The number of mutations at codon 315 was high, which is consistent with cases described in Brazil and in other countries, and the analysis of region 1 resulted in a 9.2% increase in the rate at which mutations were identified.

Keywords: Isoniazid; Mutation; Tuberculosis; Drug resistance, multiple.

Objective: To determine the drug resistance profile of Mycobacterium tuberculosis in the state of Mato Grosso do Sul, Brazil, between 2000 and 2006. Methods: Descriptive study of reported tuberculosis cases in the Brazilian Case Registry Database. We included only those cases in which M. tuberculosis culture was positive and sensitivity to drugs (rifampicin, isoniazid, streptomycin and ethambutol) was tested. Löwenstein-Jensen and Ogawa-Kudoh solid media were used for cultures, as was an automated liquid medium system. Sensitivity tests were based on the proportion method. Results: Among the 783 cases evaluated, males predominated (69.7%), as did patients in the 20-49 year age bracket (70%), a diagnosis of pulmonary tuberculosis (94.4%) and positive HIV serology (8.6%); 645 (82.4%) were new cases, and 138 (17.6%) had previously been treated. Resistance to at least one drug was found in 143 cases (18.3%). The primary resistance (PR) rate was, respectively, 8.1%, 1.6%, 2.8% and 12.4%, for monoresistance, multidrug resistance (MDR), other patterns of resistance and resistance to at least one drug, whereas the acquired resistance (AR) rate was 14.5%, 20.3%, 10.9% and 45.7%, respectively, and the combined resistance (CR) rate was 9.2%, 4.9%, 4.2% and 18.3%, respectively. In PR, streptomycin was the most common drug, whereas isoniazid was the most common in AR and CR (7.2% and 3.7%, respectively). Conclusions: These high levels of resistance undermine the efforts for tuberculosis control in Mato Grosso do Sul. Acquired MDR was 12.7 times more common than was primary MDR, demonstrating that the previous use of drug therapy is an indicator of resistance. These levels reflect the poor quality of the health care provided to these patients, showing the importance of using the directly observed treatment, short course strategy, as well as the need to perform cultures and sensitivity tests for the early diagnosis of drug resistance.

Keywords: Tuberculosis; Drug resistance, multiple; Mycobacterium tuberculosis.

Objective: Mycobacteriosis is frequently diagnosed among HIV-infected patients. In Mozambique, where few patients are under antiretroviral therapy and the prevalence of tuberculosis is high, there is need for better characterization of mycobacteria at the species level, as well as for the identification of patterns of resistance to antituberculous drugs. Methods: We studied a sample of 503 HIV-infected individuals suspected of having pulmonary tuberculosis. Of those 503, 320 tested positive for mycobacteria through sputum smear microscopy or culture of bronchoalveolar lavage fluid. Results: Acid-fast bacilli were observed in the sputum of 73% of the individuals presenting positive cultures. Of 277 isolates tested, only 3 were nontuberculous mycobacteria: 2 were identified as Mycobacterium avium and one was identified as M. simiae. Strains initially characterized as M. tuberculosis complex through polymerase chain reaction restriction analysis (PRA) of the hsp65 gene were later confirmed as such through PRA of the gyrB gene. Among the M. tuberculosis isolates, resistance patterns were as follows: to isoniazid, 14%; to rifampin, 6%; and multidrug resistance, 5%. Previously treated cases showed significantly higher rates of resistance to first-line antituberculous drugs. The most common radiological pattern was interstitial infiltrate (in 67%), followed by mediastinal lymph node enlargement (in 30%), bronchiectasis (in 28%), miliary nodules (in 18%) and cavitation (in 12%). Patients infected with nontuberculous mycobacteria presented clinical profiles indistinguishable from those of other patients. The median CD4 lymphocyte count in this group was 134 cells/mm3. Conclusions: There is a strong association between tuberculosis and AIDS in Mozambique, as expected in a country with a high prevalence of tuberculosis. Although drug resistance rates are high, the isoniazid-rifampin regimen continues to be the appropriate choice for initial therapy.

Keywords: Tuberculosis; Mycobacteria, atypical; HIV; Acquired immunodeficiency syndrome; Drug Resistance, Multiple; Mozambique.

This retrospective molecular study involving restriction fragment length polymorphism, using insertion sequence 6110 as a marker, was conducted in order to provide an initial insight into the genetic diversity of Mycobacterium tuberculosis strains isolated in the slums of the Complexo de Manguinhos, located in the city of Rio de Janeiro, Brazil. Of the 67 strains evaluated, 23 (34.3%) were found to belong to clusters (total clusters, 10). Household and social chains of transmission were associated with clustering, in 20% and 60%, respectively. Living in the Conjunto Habitacional Programado 2 slum was associated with clustering. Although not significant, it is relevant that 26% of the clustered strains presented primary resistance. These findings, although possibly underestimating the prevalence due to the failure to analyze all strains, could help improve the local tuberculosis control program.

Keywords: Tuberculosis; Epidemiology, molecular; Mycobacterium tuberculosis/transmission; Polymorphism, Restriction Fragment Length.

Objective: To evaluate the incidence of Mycobacterium tuberculosis infection, using tuberculin skin test, among community health agents (CHAs) monitoring TB patients in the city of Cachoeiro de Itapemirim, Brazil. Methods: We included 30 CHAs acting in the Family Health Program and 30 of their family members residing in the same household. The tuberculin skin test results of each CHA were compared with those of the corresponding family member. Results: Of the 30 CHAs, 27 (90.0%) were female, compared with 23 (76.7%) of the 30 family members (p = 0.299). The mean age of the CHA group and of the family member group was, respectively, 36.8 and 39.7 years. No statistically significant difference was found between the groups regarding the level of education. Regarding M. tuberculosis exposure, the same number of participants in the two groups reported having known or had contact with a TB patient (17 individuals; 56.7%). There was a statistically significant difference regarding positive tuberculin skin test results (26.7% in the CHA group and 3.3% in the family member group; p = 0.011). Conclusions: M. tuberculosis infection was significantly higher among CHAs than among their family members, fueling the debate on the occupational risk involved in the activities of these professionals.

Keywords: Community health aides; Tuberculosis; Tuberculin test.

Introduction: The teaching hospital, HUCFF, Southeastern Brazil, annually receives three hundred tuberculosis cases. Medical students have their practice at that hospital. Objective: To determine the prevalence of Mycobacterium tuberculosis (Mtb) infection among the students of the UFRJ School of Medicine. Design: Cross-sectional study of medical students at different levels of their training programs. Information about social and demographic characteristics, BCG vaccination history, and potential exposures to tuberculosis were obtained with a standardized questionnaire. Tuberculin skin testing was used to determine the prevalence of tuberculosis infection. Results: The prevalence of tuberculin skin testing positivity among medical students increased as they advanced to higher training levels (4.6%, 7.8%, 16.2%, respectively; P = 0.002). The risks were greatest during the years of clinical training, when medical students had more contact with patients. Conclusions: Medical students in the HUCFF/UFRJ may be at an increased risk of M. tuberculosis infection. A program of routine tuberculin skin testing, combined with interventions to confirm TST conversion and to reduce the risk of nosocomial transmission in the workplace is needed.

Keywords: Nosocomial infection. Medical students. Risk factors. Cross-sectional studies.

Mycobacterium tuberculosis is one of the most successful human pathogens. Highly virulent strains, which are more easily transmitted than are less virulent strains, elicit variable immune responses. We evaluated the Th1 responses (IFN-γ production) in healthy volunteers after stimulation with various strains. Our results show that the individuals with negative tuberculin skin test (TST) results were not necessarily naive to all of the strains tested, whereas individuals with positive TST results did not respond to all of the strains tested. Drug-resistant strains induced a lower mean level of IFN-γ production than did drug-sensitive strains. One possible practical application of this finding would be for the prediction of responses to treatment, in which it might be advantageous to have knowledge of the estimated IFN-γ production elicited by a specific isolated strain.

Keywords: Tuberculosis; Polymorphism, restriction fragment length; Mycobacterium tuberculosis; Immunity, cellular; Interferon-gamma.

Background: Tuberculosis become important challenge to health care settings. Brazil has high prevalence of the disease and Rio de Janeiro has high incidence rates with 30% of cases notified at hospitals. Objective: To evaluate prevalence of initial and acquired drug resistance at a general hospital, reference for aids treatment in Rio de Janeiro and to identify associated factors. Methods: Mycobacterium tuberculosis strains from 165 patients were analyzed, between August 1996 and February 1998. Results: Twenty per cent (33/165) were resistant to at least one drug; 13% (12/165) to isoniazid; 3.64% (6/ 165) to rifampin and 3.64% (6/165) to both. Among HIV seropositive subjects (52/165); 28.85% (15/52) were resistant to at least one drug. Acquired resistance occurred in 15.79% of 19 patients that mentioned previous antiTB treatment. Association statistically significant was found with non cavitation on X-ray in bivariate analyses ( P=0.05). Eighty four patients refereed no previous treatment (NPT). Resistance to 1 or more drugs was found in 28.57% (24/84) of NPT patients. Association statistically significant with initial resistance was found with health care workers (P=0.004), unemployment (P=0.03), and diarrhea (P=0.01) in bivariate analyses. On multivariate analyses, health care workers ( P=0.002) remained significantly associated with initial resistance. Conclusions: High resistance rates was found. It corroborates that hospitals needs attention for TB control especially which concerns to health care works infection.

Keywords: Mycobacterium tuberculosis. Drug resistance. Disease transmission, patient to professional. Hospitals.

Background: Tuberculosis is an ancient disease, which still remains one of the major ills faced by mankind in the 21st century. In recent decades, new technologies employing the knowledge gained from molecular biology studies have allowed for more accurate detection of tuberculosis and increased investigation of the etiology and epidemiology of the disease. Aim: Evaluating the degree of similarity among strains of Mycobacterium tuberculosis provided by the Phthisiology Sector of Centro de Saúde Navegantes (Navegantes Health Clinic) in Porto Alegre, RS, Brazil. Method: A retrospective study was performed involving RFLP typing of 55 sputum samples from outpatients examined at the Centro de Saúde Navegantes. The results of the genotyping were correlated to the conventional epidemiology data. Results: A single pattern was seen in 39 (70.9%) of the isolates, whereas 16 isolates (29.1%) showed clustering patterns and were grouped into 8 clusters of 2 patients each. An epidemiological link was found for 6 (37.5%) of the 16 patients in the clusters. Conclusion: The appropriate combination of conventional epidemiology and genotyping of M. tuberculosis contributes to a better understanding of the dynamics of tuberculosis transmission even when such a study is performed in a single, isolated health clinic.

Keywords: Mycobacterium tuberculosis. Transmission. Polymorphism, Restriction Fragment Length. Epidemiology.