Evaluation of a commercial test based on ligase chain reaction for direct detection of Mycobacterium tuberculosis in respiratory specimens

A ligase chain reaction DNA amplification method for direct detection of Mycobacterium tuberculosis (Abbott LCx MTB) in respiratory specimens was evaluated. Results from LCx MTB Assay were compared with those from acid fast bacilli smear, culture, and final clinical diagnosis for each patient. A total of 297 respiratory specimens (sputum and bronchial lavage) from 193 patients were tested. The sensitivity, specificity, positive predictive value and negative predictive value of LCx vs culture were 92.7%, 93%, 67.8% and 98.7%, respectively. When compared to the clinical final diagnosis, the sensitivity, specificity, PPV and NPV for LCx were 88.9%, 96.8%, 86.5% and 97.4%, respectively. The sensitivity of LCx MTB assay was 75% for smear-negative, culture positive samples. The results indicate that LCx MTB assay is a rapid, simple and valuable technique as a complementary tool for the diagnosis of tuberculosis.

Prevalence and incidence of Mycobacterium tuberculosis infection in nursing students in Vitória, Espírito Santo

This prospective study evaluated the incidence of Mycobacterium tuberculosis infection among nursing students at the Federal University of Espírito Santo, using the purified protein derivative test. In parallel, we evaluated whether knowledge on tuberculosis transmission mechanisms had any impact on nursing students' attitudes in relation to the risk of tuberculosis infection. The incidence of tuberculin conversion was 10.5% per year (p=0.035, 95% CI = 3.63-17.43), whereas the expected conversion rate in the overall population in Brazil is 0.5% per year. These results indicate nursing students as a group at risk for TB infection. Among the risk factors studied only the use of NIOSH95 masks was associated with protection against infection (RR=0.2). Furthermore there was no statistical difference among students that PPD converted and those who remained negative regarding disease knowledge and the existence of adequate facilities for patient hospitalization. Our data reinforces the need for implementing special biosafety programs targeting this professional group.

The secretory immunoglobulin A response to Mycobacterium tuberculosis in a childhood population

We report on the measurement of saliva anti-Purified Protein Derivative sIgA and 38kDa antibodies from 127 children, of whom 31 were strong tuberculosis suspects and 96 were healthy contact children. The results concerning the percentage of children with antibody reactivity to PPD and 38kDa antigens showed that, of these 2 antigens, 38kDa induced higher reactivity in patients positive and negative for the Tuberculin Skin Test (28% and 16.6%, respectively) in comparison to controls positive and negative for the TST (11.7% and 7.1%, respectively). There was a statistically significant difference between patients positive and controls negative for the TST. In relation to the Purified Protein Derivative antigen, while 14.2% of patients positive for the TST showed antibody reactivity to the PPD antigen, no patients negative for the TST had reactivity to this antigen. The findings suggest that these two antigens seem be associated with a different development of the mucosal defence mechanisms mediated by sIgA against Mycobacterium tuberculosis.

Simultaneous occurrence of pulmonary tuberculosis and carcinomatous lymphangitis

Tuberculosis is an important cause of mortality due to its high prevalence, considering that one third of the world’s population is infected with the tuberculosis bacillus. We report the first case of carcinomatous lymphangitis associated with active pulmonary tuberculosis. Carcinomatous lymphangitis is a rare event that may be confounded with tuberculosis because of its radiographic and clinical characteristics.

Nosocomial Mycobacterium tuberculosis transmission among healthcare students in a high incidence region, in Vitória, State of Espírito Santo

This open comparative study for evaluating hypersensitivity to tuberculin among medical students (n=441), nursing students (n=178) and economics students (n=230) in Vitória, State of Espírito Santo, had the aim of assessing whether the prevalence of positive tuberculin tests among healthcare students could be used as a sentinel event for nosocomial transmission in localities with high endemicity. There was a significant change in the frequency of purified protein derivative reactivity in the nursing students (20. 3%) and medical students (18. 4%), in comparison with the economics students (6%) (p <0. 001). As expected, the medical and nursing students had more knowledge about tuberculosis than did the economics students (p <0. 001). Our data suggest that the incidence of Mycobacterium tuberculosis infection among nursing and medical students in our region, which has high endemicity of tuberculosis, does not differ from what is found in low-incidence countries. These data reinforce the need for implementing biosafety programs for this target population.

Clinical and radiographic features of HIV-related pulmonary tuberculosis according to the level of immunosuppression

Medical charts and radiographs from 38 HIV-infected patients with positive cultures for Mycobacterium tuberculosis from sputum or bronchoalveolar lavage were reviewed in order to compare the clinical, radiographic, and sputum bacilloscopy characteristics of HIV-infected patients with pulmonary tuberculosis according to CD4+ lymphocyte count (CD4). The mean age of the patients was 32 years and 76% were male. The median CD4 was 106 cells/mm³ and 71% had CD4 < 200 cells/mm³. Sputum bacilloscopy was positive in 45% of the patients. Patients with CD4 < 200 cells/mm³ showed significantly less post-primary pattern (7% vs. 63%; p = 0.02) and more frequently reported weight loss (p = 0.04). Although not statistically significant, patients with lower CD4 showed lower positivity of sputum bacilloscopy (37% vs. 64%; p = 0.18). HIV-infected patients with culture-confirmed pulmonary tuberculosis had a high proportion of non-post-primary pattern in thoracic radiographs. Patients with CD4 lower than 200 cells/mm³ showed post-primary patterns less frequently and reported weight loss more frequently.

High frequency of resistance to the drugs isoniazid and rifampicin among tuberculosis cases in the city of Cabo de Santo Agostinho, an urban area in Northeastern Brazil

The objective of the present study was to investigate the frequency and risk factors for developing multidrug-resistant tuberculosis in Cabo de Santo Agostinho, PE. This was a prospective study conducted from 2000 to 2003, in which suspected cases were investigated using bacilloscopy and culturing. Out of 232 confirmed cases of tuberculosis, culturing and antibiotic susceptibility tests were performed on 174. Thirty-five of the 174 cultures showed resistance to all drugs. The frequencies of primary and acquired resistance to any drug were 14% and 50% respectively, while the frequencies of primary and acquired multidrug resistance were 8.3% and 40%. Previous tuberculosis treatment and abandonment of treatment were risk factors for drug resistance. The high levels of primary and acquired resistance to the combination of isoniazid and rifampicin contributed towards the difficulties in controlling tuberculosis transmission in the city.

Tuberculosis incidence and risk factors among patients living with HIV/AIDS in public health service institutions in Brasilia, Federal District

In order to estimate the incidence of and risk factors for developing tuberculosis, the clinical charts of a retrospective cohort of 281 HIV-positive adults, who were notified to the AIDS Program of the Health Department of Brasilia in 1998, were reviewed in 2003. All the patients were treatment-naive regarding antiretroviral therapy at the time of inclusion in the cohort. Twenty-nine patients were identified as having tuberculosis at the start of the study. Thirteen incident tuberculosis cases were identified during the 60 months of follow-up, with an incidence density rate of 1.24/100 person-years. Tuberculosis incidence was highest among patients with baseline CD4+ T-lymphocyte counts < 200 cells/µl who were not using antiretroviral therapy (incidence = 5.47; 95% CI = 2.73 to 10.94). Multivariate analysis showed that baseline CD4+ T-lymphocyte counts < 200 cells/µl (adjusted hazard ratio [AHR] = 5.09; 95% CI = 1.27 to 20.37; p = 0.02) and non-use of antiretroviral therapy (AHR = 12.17; 95% CI = 2.6 to 56.90; p = 0.001) were independently associated with increased risk of tuberculosis.

Recurrent Acremonium infection in a kidney transplant patient treated with voriconazole: a case report

Acremonium infection is rare and associated with immunosuppression. A case of recurrent cutaneous Acremonium infection after short term voriconazole use is described. Surgical resection was the definitive therapy. Oral voriconazole was used in the treatment of Acremonium infection, but recurrence was associated with short therapy. Prolonged antifungal therapy and surgical resection are discussed for the treatment of localized lesions.

Co-infection and risk factors of tuberculosis in a Mexican HIV+ population

INTRODUCTION: The situation of tuberculosis (TB) is being modified by the human immunodeficiency virus (HIV), which is increasing the occurrence of new cases and the generation of drug resistant strains, affecting not only the people infected with HIV, but also their close contacts and the general population, conforming a serious public health concern. However, the magnitudes of the factors associated to this co-infection differ considerably in relation to the population groups and geographical areas. METHODS: In order to evaluate the prevalence and risk factors for the co-infection of tuberculosis (TB) in a population with human immunodeficiency virus (HIV+) in the Southeast of Mexico, we made the analysis of clinical and epidemiological variables and the diagnosis of tuberculosis by isolation of mycobacteria from respiratory samples. RESULTS: From the 147 HIV+ individuals analyzed, 12 were culture positive; this shows a prevalence of 8% for the co-infection. The only variable found with statistical significance for the co-infection was the number of CD4-T < 200 cells/mm³, OR 13 (95%, CI 2-106 vs 12-109). CONCLUSIONS: To our knowledge this is the first report describing the factors associated with tuberculosis co -infection with HIV in a population from Southern Mexico. The low number of CD4 T-cells was the only variable associated with the TB co-infection and the rest of the variables provide scenarios that require specific and particular interventions for this population group.

Drug resistance of Mycobacterium tuberculosis strains in southern Brazil

INTRODUCTION: The aim of this work was to evaluate the prevalence of Mycobacterium tuberculosis (MT) strains with mutations that could result in resistance to the main drugs used in treatment in a region with one of the highest numbers of tuberculosis (TB) cases in southern Brazil. METHODS: Deoxyribonucleic acid (DNA) from 120 sputum samples from different patients suspicious of pulmonary tuberculosis who attended the Municipal Public Laboratory for Mycobacterium sp. diagnosis was directly amplified and analyzed by PCR-SSCP. The DNA was amplified in known hotspot mutation regions of the genes rpoB, ahpC, embB, katG, inhA, and pncA. RESULTS: The percentage of samples positive by culture was 9.2% (11/120); 5% (6/120) were positive by bacilloscopy and MT-PCR, and DNA fragments of the aforementioned resistance genes could be amplified from seven (7) of the eleven (11) samples with positive results, either by culture or PCR/bacilloscopy. All presented a SSCP pattern similar to a native, nonresistant genotype, with the ATCC strain 25177 as control, except for one sample (0.01%), which presented a SSCP profile demonstrating mutation at the embB gene. CONCLUSIONS: These results are consistent with the empirical observations by physicians treating TB patients in our region of a low occurrence of cases that are refractory to conventional treatment schemes, in contrast to other parts of the country. Continued surveillance, especially molecular, is essential to detect and monitor the outbreak of MT-resistant strains.

Improving tuberculosis control through the partnership between university and the health system

INTRODUCTION: Tuberculosis (TB) control is linked to the availability of qualified methods for microbiological diagnostics; however, microscopy with limited sensitivity is the only method available in many locations. The objective of this study was to evaluate the introduction of culture, drug susceptibility testing (DST), and genotyping in the routine of a Municipal Program of Tuberculosis Control. METHODS: Direct microscopy of sputum and culture in Ogawa-Kudoh were performed on 1,636 samples from 787 patients. DST of positive cultures was performed by resazurin microtiter assay and genotyping by mycobacterial interspersed repetitive units-variable number tandem repeat. RESULTS: A total 91 patients with TB were identified. The culture increased case detection by 32% compared with the microscopy; acquired resistance was 3.3% and the genotyping showed high genetic diversity. CONCLUSIONS: Ogawa-Kudoh contributed significantly to the increase in case detection and is suitable for implementation in poor-resource locations. The acquired resistance rate was lower than that reported in a recent Brazilian survey. The high genetic diversity is possibly related to the high TB prevalence in the population, as well as to early detection and suitable treatment of patients. The interaction between research and health care is important for reorienting the practice, transferring technology, and improving TB control.

Primary multidrug-resistant tuberculosis and its control implications in the State of Amazonas, Brazil: report of 3 cases

The occurrence of tuberculosis with first-line multidrug resistance leads to the use of alternative medications, often at higher costs, longer treatment periods, and greater clinical complexity. Here, we report 3 patients with multidrug-resistant tuberculosis. One patient with human immunodeficiency virus died before the sensitivity test was performed. The early diagnosis of multidrug-resistant tuberculosis and appropriate treatment should be priorities of the National Tuberculosis Control Program in order to break the chain of transmission. In addition, the possibility of substituting the proportion method with more modern and faster techniques should be urgently evaluated.

Spatio-temporal patterns of tuberculosis incidence in Ribeirão Preto, State of São Paulo, southeast Brazil, and their relationship with social vulnerability: a Bayesian analysis

INTRODUCTION: The purpose of this ecological study was to evaluate the urban spatial and temporal distribution of tuberculosis (TB) in Ribeirão Preto, State of São Paulo, southeast Brazil, between 2006 and 2009 and to evaluate its relationship with factors of social vulnerability such as income and education level. METHODS: We evaluated data from TBWeb, an electronic notification system for TB cases. Measures of social vulnerability were obtained from the SEADE Foundation, and information about the number of inhabitants, education and income of the households were obtained from Brazilian Institute of Geography and Statistics. Statistical analyses were conducted by a Bayesian regression model assuming a Poisson distribution for the observed new cases of TB in each area. A conditional autoregressive structure was used for the spatial covariance structure. RESULTS: The Bayesian model confirmed the spatial heterogeneity of TB distribution in Ribeirão Preto, identifying areas with elevated risk and the effects of social vulnerability on the disease. We demonstrated that the rate of TB was correlated with the measures of income, education and social vulnerability. However, we observed areas with low vulnerability and high education and income, but with high estimated TB rates. CONCLUSIONS: The study identified areas with different risks for TB, given that the public health system deals with the characteristics of each region individually and prioritizes those that present a higher propensity to risk of TB. Complex relationships may exist between TB incidence and a wide range of environmental and intrinsic factors, which need to be studied in future research.