Tuberculosis in a southern Brazilian prison.

The occurrence of tuberculosis (TB) in prisons has been described as an alarming public health problem in many countries, especially in developing nations. The objective of this study was to conduct a survey among prisoners with TB respiratory symptoms in order to estimate the incidence of the disease, to analyze the drug susceptibility profile and genotype the isolates of Mycobacterium tuberculosis in the city of Charqueadas, southern of Brazil. The TB incidence was 55/1,900 inhabitants in the prison; this corresponds to an incidence of 3,789/100,000 inhabitants, with a prevalence of 72/1,900 (4,960/100,000 inhabitants).

Spoligotypes of Mycobacterium tuberculosis complex isolates from patients residents of 11 states of Brazil.

One of the high tuberculosis (TB) incidence countries in the world, Brazil is characterized by considerable differences in TB incidence on regional and state level. In the present study, we describe Brazilian spoligotypes of 1991 Mycobacterium tuberculosis complex (MTC) clinical isolates from patients residents of 11 states from different regions of the country, diagnosed between 1996 and 2005. By performing spoligotyping on a large number of M.

Colorimetric microwell plate reverse-hybridization assay for Mycobacterium tuberculosis detection.

Direct smear examination using Ziehl-Neelsen staining for pulmonary tuberculosis (PTB) diagnosis is inexpensive and easy to use, but has the major limitation of low sensitivity. Rapid molecular methods are becoming more widely available in centralized laboratories, but they depend on timely reporting of results and strict quality assurance obtainable only from costly commercial kits available in high burden nations. This study describes a pre-commercial colorimetric method, Detect-TB, for detecting Mycobacterium tuberculosis DNA in which an oligonucleotide probe is fixed onto wells of microwell plates and hybridized with biotinylated polymerase chain reaction amplification products derived from clinical samples.

Comparison of two laboratory-developed PCR methods for the diagnosis of pulmonary tuberculosis in Brazilian patients with and without HIV infection.

Background: Direct smear examination with Ziehl-Neelsen (ZN) staining for the diagnosis of pulmonary tuberculosis (PTB) is cheap and easy to use, but its low sensitivity is a major drawback, particularly in HIV seropositive patients. As such, new tools for laboratory diagnosis are urgently needed to improve the case detection rate, especially in regions with a high prevalence of TB and HIV.

Objective: To evaluate the performance of two in house PCR (Polymerase Chain Reaction): PCR dot-blot methodology (PCR dot-blot) and PCR agarose gel electrophoresis (PCR-AG) for the diagnosis of Pulmonary Tuberculosis (PTB) in HIV seropositive and HIV seronegative patients.

Prospective study applying spoligotyping directly to DNA from sputum samples of patients suspected of having tuberculosis.

A prospective study was designed to evaluate the clinical usefulness of spoligotyping applied directly to sputum samples. Patients suspected of having tuberculosis were recruited at the Hospital Sanatorio Partenon in Porto Alegre, Brazil. Of the 197 samples included in the analysis, 175 (88.

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.

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.

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.

Phenotypic and genotypic characterization of drug-resistant Mycobacterium tuberculosis strains.

Of 142 pulmonary tuberculosis patients, 76 were considered high risk for the development of resistance, and 24 were confirmed as resistant strain carriers. Resistant isoniazid strains presented a high frequency of katG and ahpC mutations (90%) correlated with an MIC >4 microg/mL (94%). inhA mutations were not seen.

PCR colorimetric dot-blot assay and clinical pretest probability for diagnosis of Pulmonary Tuberculosis in smear-negative patients.

Background: Smear-negative pulmonary tuberculosis (SNPTB) accounts for 30% of Pulmonary Tuberculosis (PTB) cases reported annually in developing nations. Polymerase chain reaction (PCR) may provide an alternative for the rapid detection of Mycobacterium tuberculosis (MTB); however little data are available regarding the clinical utility of PCR in SNPTB, in a setting with a high burden of TB/HIV co-infection.

Methods: To evaluate the performance of the PCR dot-blot in parallel with pretest probability (Clinical Suspicion) in patients suspected of having SNPTB, a prospective study of 213 individuals with clinical and radiological suspicion of SNPTB was carried out from May 2003 to May 2004, in a TB/HIV reference hospital.

Evaluation and genotyping of multidrug-resistant cases of tuberculosis in southern Brazil.

Sixty isolates of Mycobacterium tuberculosis identified as multidrug-resistant (MDR) at a reference laboratory in Rio Grande do Sul State during the years 1999 and 2000 were analyzed using the IS6110-restriction fragment length polymorphism (RFLP) technique. We also genotyped 202 susceptible strains to compare the genotyping results, as well as the clinical and demographic data. Spacer oligotyping (spoligotyping) analysis was performed for isolates presenting low IS6110 copy number.

Mycobacterium tuberculosis complex genetic diversity: mining the fourth international spoligotyping database (SpolDB4) for classification, population genetics and epidemiology.

Background: The Direct Repeat locus of the Mycobacterium tuberculosis complex (MTC) is a member of the CRISPR (Clustered regularly interspaced short palindromic repeats) sequences family. Spoligotyping is the widely used PCR-based reverse-hybridization blotting technique that assays the genetic diversity of this locus and is useful both for clinical laboratory, molecular epidemiology, evolutionary and population genetics. It is easy, robust, cheap, and produces highly diverse portable numerical results, as the result of the combination of (1) Unique Events Polymorphism (UEP) (2) Insertion-Sequence-mediated genetic recombination.

Characterization of pncA mutations in pyrazinamide-resistant Mycobacterium tuberculosis in Brazil.

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.