Laboratory Diagnosis Of Tuberculosis Research Articles

Comparação de métodos de cultivo para o diagnóstico laboratorial da tuberculose pulmonar

This study aimed to evaluate different methods for culturing sputum, Ogawa-Kudoh (O - K) and Petroff, using reduced time for decontamination (Petroff - R), expecting to know their effectiveness in tuberculosis laboratory diagnosis. Four hundred and fifty-nine sputum samples of patients with pulmonary symptoms were cultured using O - K and Petroff - R, to be compared with the regular Petroff method. O - K and Petroff - R methods showed efficient sensitivity in isolating Mycobacterium tuberculosis and micobacteria other than tuberculosis, even in samples with negative acid fast smear. Statistics analysis showed similar contamination rate for O - K when compared to Petroff. These data suggest that O-K, being easy to perform, having low costs, presenting low risk of worker contamination and good sensitivity in detecting M. tuberculosis, should be used in clinical laboratories as a good resource at tuberculosis diagnosis

Advances in the Diagnosis of Tuberculosis: The Way Forward for Resource-Poor Countries: Review

Tuberculosis (TB) is a highly contagious disease and requires rapid diagnosis for case detection and treatment. In order to appraise the impact of laboratory diagnosis of TB on current efforts to control the disease, available tests for the diagnosis of TB in both developed and developing countries were reviewed from leading journal articles and TB websites. Current trends in TB diagnosis showed that sputum smear microscopy is the basis of diagnosis for tuberculosis in developing countries has been adopted for case detection in tuberculosis control programmes. In contrast, the trend in developed countries reveals the availability of sophisticated, rapid tests that compliment smear microscopy. Although it is common knowledge that the HIV/AIDS pandemic in the poor nations of world is a major contributory factor to the heightening incidence of TB in those nations, it may be necessary to insinuate other more subtle factors. Among such factors may be the state of laboratory diagnosis that directly impacts on case detection. Perhaps a strengthening a strengthening of laboratory facilities in resource-limited countries of the world may effectively reduce the continued increase in TB case notification in these countries. Key Words: Tuberculosis, Diagnosis, Smear Microscopy, Rapid Methods, Culture Mary Slessor Journal of Medicine Vol.4(1) 2004: 18-26

Childhood tuberculosis and its early diagnosis

Traditional methods for laboratory diagnosis of tuberculosis are unsatisfactory, especially for children, in whose specimens mycobacteria are usually sparse. Recent changes in tuberculosis epidemiology in developed countries, including a large increase in incidence in children from certain ethnic minorities, have prompted interest in newer diagnostic methods. Liquid-based culture detection systems offer improved sensitivity and speed of diagnosis, although the time taken for d etection of growth is still upwards of 1 week. Nucleic acid amplification techniques offer more rapid results, but perform best on smear-positive samples; sensitivities may be as low as 50% in smear-negative specimens. Although these newer techniques are widely used in some developed countries, in others, they are not perceived as offering sufficient benefit to justify their routine use. The diagnostic accuracy of mycobacteriophage and serologic methods is insufficient to justify their wide use even in developing countries. Despite recent developments, there is still no panacea for diagnosis of childhood tuberculosis.

EVALUATION OF AN OGAWA MYCOBACTERIUM CULTURE METHOD MODIFIED FOR HIGHER SENSITIVITY EMPLOYING CONCENTRATED SAMPLES

Two egg-based culture media were evaluated for detection of mycobacteria with Lowenstein-Jensen (L-J) as a gold standard. The conventional culture method was modified to improve laboratory diagnosis of tuberculosis in resource scarce countries by employing an inexpensive but sensitive and specific culture method. Sputum samples were collected from pulmonary tuberculosis suspects who visited the chest clinic at the University Teaching Hospital in Zambia. These samples were processed using three different sample treating procedures (with or without sample concentration) and cultured on L-J and Ogawa media for mycobacteria isolation. A total of 276 sputum samples were collected from 138 pulmonary tuberculosis suspects. When the L-J result was used as a standard, the sensitivity of Ogawa and modified Ogawa was 81.7% and 90.3% respectively. Similarly, the specificities of those methods were 96.7% and 92.3% respectively. In total, 90 samples (32.6%) were smear positive and 108 (39.1%) were culture positive. The positivity of each culture method was as follows: 93 (33.7%) in L-J, 98 (35.5%) in modified Ogawa, and 82 (29.7%) in original Ogawa. The contamination rate was 1.1%, 5.1%, and 9.8% for L-J, Ogawa and modified Ogawa respectively. The Ogawa culturing method is economical, simple and quick. Its low sensitivity was overcome by employing the concentration method, the sensitivity significantly improving from 81.7% to 90.3%. Ogawa techniques are ideal in overburdened TB laboratories with poor resources in developing countries.

Mycobacteria and TB

Tuberculosis as a Global Public Health Problem, D.A. Enarson New Perspectives in the Molecular Epidemiology of Tuberculosis, D. van Soolingen, K. Kremer, E. Vynycky Vaccination - The Current Status of BCG, C.J. Clements Laboratory Diagnosis of Tuberculosis, G.E. Pfyffer Mycobacteria and TB - Therapy and Drug Resistance, S. Niemann, S. Rusch-Gerdes Molecular Biology of Mycobacterium tuberculosis, G. Saunders, J. McFadden Immunology and Persistence, T. Ulrichs, S.H.E. Kaufmann New Strategies for the Design of Vaccines against Tuberculosis, B. Gicquel Modern Drug Development, C.E. Barry III.

A national audit of the laboratory diagnosis of tuberculosis and other mycobacterial diseases within the United Kingdom.

In order to audit United Kingdom laboratory diagnostic and reference services including novel molecular methods for tuberculosis, a questionnaire was sent to laboratories submitting specimens to the PHLS Mycobacterium Reference...

Critical Assessment of Gene Amplification Approaches on the Diagnosis of Tuberculosis

The resurgence of tuberculosis prompted the development of a number of new options for the rapid laboratory diagnosis of Mycobacteriun tuberculosis (MTB). One of the most promising and exciting methodologies has been the introduction of assays employing amplification technology to detect MTB directly in clinical specimens. Although amplification assays hold significant promise to improve the laboratory diagnosis of tuberculosis, the decision to perform or not perform these assays is complicated. The performance of in-house polymerase chain reaction (PCR) assays and two commercially-prepared assays, GenProbe's AMTD test and Roche's AMPLICOR PCR assay are reviewed. Regardless of the amplification format, all assays have decreased sensitivity with specimens that are acidfast bacilli (AFB) stain-negative. Data from these studies and others indicate possible potential pitfalls of amplification assays, those being sampling errors, the presence of substances in clinical specimens that inhibit the amplification assay, and clinical utility.In light of these findings, the possible roles for these assays in the clinical microbiology laboratory are reviewed. In addition, factors such as cost, assay performance, etc. are discussed in order to facilitate the decision-making process concerning whether an amplification assay would be appropriate in a particular laboratory setting.

Reducing delays in the laboratory diagnosis of tuberculosis.

Reducing delays in the laboratory diagnosis of tuberculosis. S Krishnan, J E Koehler, R Benjamin, and A L ReingoldCopyRight https://doi.org/10.2105/AJPH.86.8_Pt_1.1171 Published Online: October 07, 2011

Direct detection of Mycobacterium tuberculosis in sputum samples from Guinea Bissau by an rRNA target-amplified test system

Setting: There is a need for more sensitive and rapid methods for laboratory confirmation in the diagnosis of tuberculosis. Objective: To investigate the applicability of a target rRNA amplified test system (AMTDT, Gen-Probe, CA) for rapid detection of Mycobacterium tuberculosis. Design: The rRNA amplified test system was compared to standard methods for acid fast microscopy and mycobacterial culture for the demonstration of M. tuberculosis in sputum samples from 247 patients in Guinea Bissau with suspected tuberculosis. Results: The highest incidence of positive samples was obtained with the AMTDT test. Out of 274 sputum samples 96 (35%) were positive by the AMTDT test, 82 (30%) were positive by culture and 38 (14%) by direct microscopy. Using culture as reference method the sensitivity of the test was 85% (after discrepancy analysis 87%), and the specificity was 86% (after discrepancy analysis 93%). Conclusion: The sensitivity and specificity of the AMTDT test used in this setting indicates that it may be a valuable complement for improving the laboratory diagnosis of tuberculosis.

On the Development of Mycobacterial Infections: I. A Review Concerning the Common Situation

In this review concerning the common situation of mycobacterial infections the following problems are discussed: (1) The worldwide epidemiological situation of tuberculosis reveals an increase in the developing countries but even in some industrialized countries like the United States. The reasons for this development are mainly socioeconomic factors. (2) The association between tuberculosis and HIV infection has caused in general a marked increase in the incidence of tuberculosis in some countries. Because of its ability to destroy the immune system, HIV is a significant risk factor for the progression of tuberculosis infection as a clinical disease. Taking into account that 5 million persons worldwide are infected with tuberculosis as well as with HIV (most of them living in the Sub-Saharan Africa), enormous future problems can be anticipated. (3) The new fear of tuberculosis has resulted mainly from reports about outbreaks with multidrug resistant strains of Mycobacterium tuberculosis in the United States. These strains are at least resistant to the most important antituberculotic drugs isoniacid and rifampicin. The frequency of multidrug-resistant tuberculosis in the USA is reported to be overall 3-7%, however for New York 19% is estimated. The main reason for this development is inadequate chemotherapy mostly due to poor compliance. Therefore in the United States the directly observed therapy has been established. Complete and reliable reports of the resistance situation in other countries are not available because most of these have no resistance surveillance programs. (4) As immunocompromised patients become more numerous, the importance of nontuberculous mycobacteria has significantly increased. Mainly organisms of the Mycobacterium avium-intracellulare complex play a special role as opportunistic pathogens for AIDS patients in later stages of their disease. Therapy for these infections is problematic due to the high resistance of most ubiquitous mycobacteria to antituberculotic drugs. (5) New laboratory techniques have shortened the detection time (radiometric culture systems) and the time needed for the identification of the most important mycobacteria species (DNA probes). A further improvement of the laboratory diagnosis of tuberculosis is expected in the near future by nucleic acid amplification techniques (polymerase chain reaction and others).

Current and future applications of mycobacterial amplification assays

Introduct ion During the last 2 to 3 yr, numerous articles have been published concerning the reemergence of tuberculosis in the U.S. This resurgence was a result of a number of complex factors, among them homelessness and other socioeconomic factors, the human immunodeficiency virus (HIV) epidemic, and hospital and other group-setting outbreaks of tuberculosis. Further complicating these outbreaks were frequent delays in laboratory repotting of smear, culture, and/or susceptibility test resuits. As a consequence, an important question was raised as to how one could provide a more rapid diagnosis for tuberculosis given the urgent need. Because of the obvious demand for a reliable and rapid means of diagnosing tuberculosis for public health and therapeutic reasons, the discovery of the polymerase chain reaction (PCR) about 10 yr ago, with its potential ability to exponentially copy virtually any targeted sequence of DNA in an afternoon, is particularly attractive. Since PCR's discovery, a number of other approaches to amplification have also been introduced to detect Mycobacterium tuberculosis (MTB) directly in clinical specimens; some of these amplification formats are listed in Table 1. Regardless of the format, these amplification assays show promise as rapid, sensitive, and specific methods to diagnose tuberculosis. Despite the significant promise these assays hold for improved laboratory diagnosis of tuberculosis, a number of issues must be considered by clinical microbiologists before these assays are introduced into the laboratory routine. Key issues include expense, the assays' exact role in the diagnosis of mycobacterial infections, and their clinical utility. In this article, I would like to discuss important issues concerning these assays and then suggest some possible immediate and future applications for them. However, if these issues are to be fully appreciated, a brief summary of data published to date is prerequisite.

Selective utilization of DNA probes for identification of Mycobacterium species on the basis of cord formation in primary BACTEC 12B cultures

Primary BACTEC 12B cultures with serpentine cords observed in Kinyoun-stained smears were tested with a probe for Mycobacterium tuberculosis complex, while cultures without cords were tested with a probe for M. avium complex. The sensitivity, specificity, and positive and negative predictive values of cording for the presumptive identification of M. tuberculosis were 95, 95, 90, and 98%, respectively. With experience, the selection of a probe for testing of primary BACTEC 12B cultures on the basis of cord formation and history of tuberculosis can provide a rapid and reliable approach to the laboratory diagnosis of tuberculosis.

Laboratory diagnosis of tuberculosis

Laboratory diagnosis of tuberculosis

Diagnostic Mycobacteriology: Current Challenges and Technologies

Tuberculosis (TB) has reemerged as a major public health problem worldwide. Although traditional acid-fast smears and cultures remain important tools for laboratory diagnosis of TB, these methods are not adequate to meet the challenges of the current crisis. In response to urgent needs for more rapid and sensitive diagnostic methods in mycobacteriology, several innovative procedures have been developed. Radiometric, molecular, biochemical, and chromatographic techniques have been introduced successfully in clinical laboratories, and others continue to be investigated. I review the newer technologies that provide laboratories with the tools necessary to achieve rapid detection, identification, and susceptibility testing of Mycobacterium tuberculosis .

Current practices in mycobacteriology: results of a survey of state public health laboratories

Fifty-six state and territorial public health laboratories were surveyed to determine whether currently available rapid methods for the identification and drug susceptibility testing of Mycobacterium tuberculosis were being performed. Forty (71%) laboratories use fluorochrome rather than conventional basic fuchsin stains for screening clinical specimens for acid-fast bacilli. Of the 55 laboratories that routinely culture for mycobacteria, 16 (29%) use the more rapid radiometric methods. Species identification of isolates is done by biochemical tests in 13 (23%) laboratories; 40 (72%) use nucleic acid probes, high-performance liquid chromatography, or the BACTEC p-nitro-alpha-acetylamino-beta-hydroxypropiophenone (NAP) test (rapid tests); 3 laboratories do not perform species identification. Drug susceptibility testing is performed with solid media by 36 of 45 (80%) laboratories, while the more rapid radiometric methods are used by 9 (20%) laboratories. Compared with the laboratories that use conventional methods, laboratories that use rapid methods report results more quickly: for species identification, 43 days (conventional) versus 22 days (rapid); for drug susceptibility testing, 44 days (conventional) versus 31 days (rapid) from specimen processing. Rapid technologies for microscopy and species identification are being used by many, but not all, state and territorial public health laboratories; however, most laboratories do not use the more rapid radiometric methods for routine culture or drug susceptibility testing of mycobacteria. Implementation of such rapid technologies can shorten turnaround times for the laboratory diagnosis of tuberculosis and recognition of drug resistance.

Nonspecificity of the Anda A60-tb ELISA test for serodiagnosis of mycobacterial disease.

The conventional methods for the laboratory diagnosis of tuberculosis and other mycobacterial diseases are time consuming and beyond the scope of most of the small and medium-sized hospital facilities. Therefore, there has been considerable interest in the development of a serological method for the detection of antibodies against mycobacteria. We recently evaluated a commercially available ELISA test (Anda Biologicals, Strasbourg, France) that measures antibody levels to A60 antigen, a membrane glycoprotein that is found in most mycobacteria. Of the 123 patients with positive pulmonary cultures for Mycobacterium tuberculosis, 82% had detectable antibodies against the kit antigen. Of the 68 patients with extrapulmonary tuberculosis, 59% yielded positive results. Specimens from 2 of the 12 patients that grew Mycobacterium avium-intracellulare complex, and one each with Mycobacterium fortuitum and Mycobacterium chelonei, were considered significant on the basis of medical history and repeated isolation of the bacterium from clinical specimens, and these patients yielded positive serology. Of the healthy, normal PPD positive and PPD negative controls, 24% gave false positive results.

Detection ofMycobacterium tuberculosisin Sputum Samples Using a Polymerase Chain Reaction

A polymerase chain reaction (PCR) assay for the rapid detection of Mycobacterium tuberculosis in sputum samples is described. The target DNA is a 123-base pair (bp) segment of IS6110, which is repeated in the M. tuberculosis chromosome and is specific for the M. tuberculosis complex. Methodology used to lyse the mycobacteria, extract the DNA, and amplify the 123-bp target DNA is presented. The amplified PCR product is detected by examination of ethidium-bromide-stained acrylamide gels. An internal control using the same primers as the target DNA has been constructed to assess the efficacy of each individual reaction. Of 162 sputum samples tested, 82 were smear-positive for acid-fast bacilli. Of the 94 specimens from patients in whom pulmonary tuberculosis was diagnosed, 51 were culture-positive, smear-positive, or both. Fifty of these were PCR positive. Of the 42 specimens from patients with nontuberculous mycobacterial pulmonary disease, 41 were PCR negative. All 26 specimens from patients without mycobacterial infection were PCR negative. This assay provides a sensitive and specific means for the laboratory diagnosis of tuberculosis within 48 h that is relatively simple to perform.

Laboratory diagnosis of tuberculosis using non-immunological tools.

Laboratory diagnosis of tuberculosis using non-immunological tools.

Advances in the diagnosis of tuberculosis.

Several advances in the laboratory diagnosis of tuberculosis have been described recently. Refinements in collection of specimens, methods of staining and culture techniques have been described. Several newer immunological tests such as ELISA, SAFA, and leucocyte migration inhibition test are useful in the diagnosis of sputum negative pulmonary tuberculosis. Indirect immunoflouresence test and leucocyte migration inhibition test are useful in determining the duration of chemotherapy. Detection of mycobacterial cellular products such as tuberculostearic acid in sputum are helpful in diagnosing sputum negative cases. This article describes briefly the principle and usefulness of these tests in diagnosis of tuberculosis.

The laboratory diagnosis of intestinal tuberculosis: a study of 50 cases.

Fifty cases of chronic benign obstructive lesions of the ilco‐caccal region have been studied. The histopathology, particularly of the lymph nodes, provides the maximal confirmatory evidence of tuberculosis. Guinea‐pig inoculation is more informative, offering greater possibilities of indentifying acid‐fast bacilli. The demonstration of granuloma formation with caseation represents a significant advance in the laboratory diagnosis of tuberculosis.