Objective: To assess the determining factors for Mycobacterium tuberculosis multidrug resistance at a referral center for infectious diseases in the state of Minas Gerais, Brazil. Methods: A retrospective case-control study was conducted using data collected from September of 2000 to January of 2004. During this period, 473 cultures presenting growth of M. tuberculosis, corresponding to 313 patients, were submitted to susceptibility tests at the Central Laboratory of Minas Gerais. Cases presenting resistance to at least rifampin and isoniazid were classified as cases of multidrug resistance and were selected for study. These cases were paired to control group cases of drug-susceptible tuberculosis at a ratio of 1:3. Clinical and demographic data were analyzed using univariate and multivariate analyses. Results: During the study period, 12 (3.83%) cases of multidrug-resistant tuberculosis were identified. In the univariate analysis, multidrug-resistant tuberculosis was found to be more common among male patients, as well as among those testing positive in the sputum smear microscopy, those with cavitations larger than 4 cm in diameter and those having been previously treated for tuberculosis (p = 0.10 for all). After the multivariate analysis, only previous treatment for tuberculosis remained statistically significant (p = 0.0374), with an odds ratio of 14.36 (1.96-176.46). Conclusion: In the present study, previous treatment for tuberculosis was found to be an independent risk factor for multidrug-resistant tuberculosis.

Keywords: Mycobacterium tuberculosis; Tuberculosis, multidrug-resistant; Tuberculosis; Microbial sensitivity tests; Risk factors

Objective: To evaluate the risk factors for the development of tuberculosis and multidrug-resistant tuberculosis (MDR-TB) in patients treated at a tertiary referral hospital. Methods: This was a cross-sectional study based on data obtained from patients treated at the Júlia Kubitschek Hospital, located in the city of Belo Horizonte, Brazil, between October of 2012 and October of 2014. We evaluated sociodemographic, behavioral, clinical, and radiological variables. The outcome considered to identify associations between tuberculosis and the explanatory variables was the treatment prescribed. To evaluate the associations between MDR-TB and the same explanatory variables, the change in MDR-TB treatment was considered. Results: The factors associated with tuberculosis were alcoholism, comorbidities, pulmonary cavitations, and a radiological pattern suggestive of tuberculosis. Cavitation and previous treatment for tuberculosis were associated with MDR-TB. Conclusions: Despite the significant progress made in the fight against tuberculosis, there is a need for coordinated actions that include social protection measures and patient support.

Keywords: Tuberculosis; Risk factors; Tuberculosis, multidrug-resistant.

Objective: To analyze the profile of tuberculosis cases reported between 2002 and 2009 in the state of Minas Gerais, Brazil, according to sociodemographic, clinical, and laboratory characteristics, as well as to comorbidities and mortality. Methods: This was a descriptive, epidemiological study based on data obtained from the Brazilian Case Registry Database and the Brazilian Mortality Database for the 2002-2009 period. Results: There were 47,285 reported cases of tuberculosis, corresponding to a mean incidence of 22.3/100,000 population. The individuals diagnosed with tuberculosis were predominantly in the 20- to 49-year age bracket and male (62.4% and 67.0%, respectively). Individuals with a low level of education accounted for 18.5% of the cases. New cases, cases of recurrence, and cases of retreatment accounted for 83.7%, 5.7%, 5.7%, respectively. The rates of cure and treatment noncompliance were 66.2% and 11.2%, respectively; multidrug-resistant tuberculosis was identified in 0.2% of the cases; and the mortality rate was 12.9%. The directly observed treatment, short-course (DOTS) strategy was applied in 21.8% of the cases. Sputum smear microscopy and culture were performed in only 73.9% and 12.9% of the cases, respectively. Chest X-rays were performed in 90.5% of the cases. Pulmonary tuberculosis was the predominant form (in 83.9%). Comorbidity with alcoholism, HIV infection, and diabetes mellitus were identified in 17.2%, 8.3%, and 3.8%, respectively. Conclusions: During the study period, the numbers of new cases, cases of treatment noncompliance, and deaths were high, comorbidities were common, and there was a failure to perform adequately basic tests for the diagnosis of tuberculosis. Multidisciplinary approaches, expanded use of the DOTS strategy, better knowledge of the distribution of tuberculosis, and improvements in the databases are needed in order to achieve better control of the disease in the state of Minas Gerais.

Keywords: Tuberculosis/epidemiology; Tuberculosis/mortality; Information systems.

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.

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.

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.

We conducted a cross-sectional, retrospective study, characterized by classical and molecular epidemiology, involving M. tuberculosis isolates from a regional prison in southern Brazil. Between January of 2011 and August of 2014, 379 prisoners underwent sputum smear microscopy and culture; 53 (13.9%) were diagnosed with active tuberculosis. Of those, 8 (22.9%) presented with isoniazid-resistant tuberculosis. Strain genotyping was carried out by 15-locus mycobacterial interspersed repetitive unit-variable-number tandem-repeat analysis; 68.6% of the patients were distributed into five clusters, and 87.5% of the resistant cases were in the same cluster. The frequency of drug-resistant tuberculosis cases and the rate of recent transmission were high. Our data suggest the need to implement an effective tuberculosis control program within the prison system.

Keywords: Tuberculosis; Prisons; Molecular epidemiology.

The correlation between resistance to pyrazinamide (PZA) and resistance to other first-line antituberculosis drugs was investigated in 395 Mycobacterium tuberculosis strains isolated from clinical specimens, representing 14% of the overall number of M. tuberculosis isolates obtained between 2003 and 2008 at the laboratory of a referral university hospital for tuberculosis. A high correlation was found between resistance to PZA and multidrug resistance, as well as between PZA resistance and resistance to rifampin, isoniazid, and ethambutol (p < 0.01 for all). These results highlight the importance of performing PZA susceptibility testing prior to the prescription of this drug in order to treat drug-resistant and multidrug-resistant tuberculosis.

Keywords: Tuberculosis/drug therapy; Tuberculosis/microbiology; Antibiotics, antitubercular.

Os bacilos que causam a tuberculose estão agrupados no complexo Mycobacterium tuberculosis, composto por: M. tuberculosis, M. bovis subsp. bovis, M. africanum e M. microti, além da cepa vacinal M. bovis BCG. Tem sido proposta a inclusão de novas espécies neste complexo, como M. canettii, uma variante de M. tuberculosis encontrada na região da Somália(1), M. caprae, agente etiológico de tuberculose em caprinos(2), e M. pinnipedii, que causa tuberculose em leões marinhos, mas que também pode infectar o homem(3).

Background: The appearance of tuberculosis/human immunodeficiency virus co-infection and the growing number of diseases caused by nontuberculous mycobacteria, as well as the confusion that these can cause in relation to emerging multidrug-resistant strains, require more accurate and rapid laboratory results, not only in the isolation of strains but also in their identification. Objective: A comparative study evaluating a new tool of molecular identification, which uses a genetic probe based on the 16S rDNA sequence of the Mycobacterium tuberculosis gene (Gen-Probe Accuprobe® Gen Probe, Inc.), and the classic methodology. Method: Fifty-five Mycobacterium strains, isolated from the sputum of patients treated at a tuberculosis reference clinic, were selected for study. Subcultures were performed in three tubes: one submitted to genetic identification, one analyzed through classical tests (production and accumulation of niacin; growth in the Lowenstein-Jensen medium with the inhibitor agents p-nitrobenzoic acid and thiophene-2-carboxylic acid hydrazide added), and one held in reserve. Results: The probe identified 51 cases as belonging to the M. tuberculosis complex (one associated with M. kansasii) and the other 4 as nontuberculous mycobacteria, later identified as M. kansasii (3) and M. avium (1). Using traditional methods, 47 samples were identified as belonging to the M. tuberculosis complex, 4 were classified as fitting the profile of nontuberculous mycobacteria (in agreement with the genetic probe results), and 4 were unidentified, 1 of which presented the exact characteristics that 2 mycobacterium species have in common. Conclusion: The benefits of the molecular biology technique justify its implementation and routine use, in combination with classical methods, in a high-traffic clinic where complex cases of tuberculosis are treated.

Keywords: Mycobacterium tuberculosis. Molecular probe techniques.

We compared the nitrate reductase assay with the proportion method, which is considered the gold standard, in 57 Mycobacterium tuberculosis strains isolated from patients treated at the Federal University of Minas Gerais Hospital das Clínicas, located in the city of Belo Horizonte, Brazil. For rifampin and isoniazid, the sensitivity, specificity, and accuracy of the nitrate reductase assay were all 100%, whereas they were 100%, 88.9%, and 66.7%, respectively, for streptomycin and 98.0%, 100%, and 98.2%, respectively, for ethambutol. The mean time to results was ten days. In the study sample, the nitrate reductase assay proved highly accurate and showed excellent concordance with the gold standard.

Keywords: Mycobacterium tuberculosis; Microbial sensitivity tests; Tuberculosis, multidrug-resistant; Nitrate reductase.

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.

In view of the fact that the World Health Organization has recommended the use of the mycobacteria growth indicator tube (MGIT) 960 system for the diagnosis of tuberculosis and that there is as yet no evidence regarding the clinical impact of its use in health care systems, we conducted a pragmatic clinical trial to evaluate the clinical performance and cost-effectiveness of the use of MGIT 960 at two health care facilities in the city of Rio de Janeiro, Brazil, where the incidence of tuberculosis is high. Here, we summarize the methodology and preliminary results of the trial. (ISRCTN.org Identifier: ISRCTN79888843 [http://isrctn.org/])

Keywords: Controlled clinical trial; Tuberculosis; Diagnostic tests, routine.

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.