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Showing 6 results for Mycobacterium Tuberculosis
Peripheral Blood Mononuclear Cell Mycobacterium tuberculosis PCR sensitivity in diagnosis of Tuberculosis
Hajiabdolbaghi M, Allishah H.a, Rasoolinejad M, Bahador A, Izadi M, Mobaien A.r,
Volume 65, Issue 11 (2-2008)
Abstract

Background: Tuberculosis is still one of the most important causes of mortality and morbidity in many countries and is the second only to human immunodeficiency virus as a cause of death worldwide resulting from a single infectious agent. In 1993, the World Health Organization declared tuberculosis a global public health emergency. Conven-tional methods for the diagnosis of Mycobacterium tuberculosis (MTB) infections are time consuming, as MTB culture requires 3-8 weeks for growth. To determine the sensitivity of polymerase chain reaction (PCR) in peripheral blood mononuclear cells (PBMC), we have evaluated Mycobacterium tuberculosis DNA in peripheral blood samples with PCR technique in adults with new cases of pulmonary and extra-pulmonary tuberculosis. Setting: Department of Infectious disease of Imam Khomeini Hospital, 2004- 2005, Tehran, Iran.

Methods: In this cross-sectional study, we evaluated MTB DNA extracted from 3ml citrated peripheral blood samples from 95 adults with new cases of pulmonary and extra-pulmonary tuberculosis. DNA extraction was performed using a commercial PCR kit with IS1081 primers. For prevention of cross contamination and reduction of false positives, all steps were performed under laminar hood.

Results: The 95 patients, 59 of whom were male, had a mean age 44.44 years (SD±20.26) 69 cases had pulmonary and 26 had extra-pulmonary tuberculosis. PCR was positive in 32 (33.7%) patients and negative in 63 (66.3%) cases. The overall sensitivity and accuracy of the PCR assay was 44.1% for pulmonary, 19.2% for extra-pulmonary and 10% for disseminated tuberculosis, respectively.

Conclusion: The low sensitivity of the IS1081 primer MTB-PCR assay on PBMC may pose problems for the rapid diagnosis of tuberculosis. However, further studies are needed to confirm this technique as an alternative test for the diagnosis of tuberculosis.


Rapid detection of Mycobacterium tuberculosis complex: PCR method using insertion sequence 6110
Rohani M, Khorshidi A, Moniri R, Torfeh M, Abddoshah F, Saffari M, Shajari Gh R, Moosavi Gh A,
Volume 67, Issue 3 (6-2009)
Abstract

Normal 0 false false false EN-GB X-NONE AR-SA MicrosoftInternetExplorer4 Background: Tuberculosis is an important cause of death in some countries. The world health organization estimates that if stronger measures are not taken up to control the prevalence of this disease, from 2000 to 2020 a billion people will be infected by the bacterium. According to time consuming of common detection methods of Mycobact-erium tuberculosis such as culture, it is necessary to evaluate a rapid detection tests such as PCR. Rapid diagnosis of tuberculosis may have profound effects in patients' care According to importance of rapid detection and treatment of tuberculosis and for determine of sensitivity, specificity, positive predictive value and negative predictive value of PCR by using IS6110 this study was done in Kashan university of medical science.
Methods: A total of 248 sputum samples from patients suspected of mycobacterial diseases were studied. DNA was extracted by boiling method. IS6110 PCR method by a specific pair of primers designed to amplify 123bp and 245bp sequences of the insertion sequence, 6110, in the M. tuberculosis genome was used to analyze sputum samples.
Results: 32 out of 248 (12.9%) of samples had positive culture. PCR yielded a sensitivity of 93.8% and specificity of 99.1% for the diagnosis of TB patients with TB confirmed by culture. There were two out of 32 (6.3%) PCR-positive cases among the patients with non-TB disease.
Conclusion: The findings of the present study indicate that Multiplex PCR may provide a faster method of detecting tuberculosis, thus enhancing diagnostic procedures and we conclude that the performance of an IS6110 PCR assay is valuable in the rapid diagnosis of tuberculosis.


Tuberculin skin test: review article
Hadi Peeridogaheh , Roghayeh Teimourpour , Mohsen Arzanlou , Sina Rostami , Elham Raeisi ,
Volume 75, Issue 8 (11-2017)
Abstract
Historically, tuberculosis has been the leading cause of death throughout human history. Tuberculosis infection (TB) causes by Mycobacterium tuberculosis that is very dangerous and can affect any parts of the body, especially lungs. Tuberculosis infection still remains a serious threat to human public health due to its contagious nature, capability to stay latent form in host for indefinite time and then appear as active disease. It is estimated that one third of world’s population, nearly 2 billion persons are infected with Mycobacterium tuberculosis. Transmission occurs among people through inhalation of infected droplets. Lungs and especially alveolar macrophage are primary sites of infection. Mycobacterium tuberculosis bacilli by preventing fusion of phagosome with lysosome can remain alive inside the macrophages. Such situation defined as latent infection. In fact, persons with latent tuberculosis infection (LTBI) are only infected with M. tuberculosis without any sign of infectious. Latent infection in compared with active infection is not contagious, but in about 10-5 percent of people will develop active tuberculosis especially in elderly and people who use immunosuppressive drugs. Pulmonary TB is an active form of tuberculosis infection in which bacteria can spread among people by infected droplets. So identifying and treating people with latent TB infection can significantly reduce the progression of latent form to active infection. The tuberculin skin test (TST) is the most widely used test in worldwide that is applied to determine a person who is infected with M. tuberculosis. TST provide valubale information for diagnosis LTBI however its specificity can be reduced by bacillus Calmette-Guérin (BCG) vaccination and infected with non-tuberculous mycobacteria (NTM). In TST test host hypersensitivity responses to Purified protein derivative (PPD) from mycobacterium are evaluated. TST positive reaction indicates the presence of high risk for acquiring TB infection or progression of latent tuberculosis to active form. Previous studies indicated that there is correlation between TST response and subsequent risk of active TB. Experimental evidence has shown that treatment of latent infection in the basis of positive TST reduces the risk of active TB. Although TST is far from gold standard but it's low cost and simplicity make it a suitable laboratory test especially in developing country.
 

Latent tuberculosis infection in health care workers: review article
Davood Mansury , Mahdis Ghavidel , Kiarash Ghazvini ,
Volume 75, Issue 10 (1-2018)
Abstract
The members of Mycobacterium tuberculosis complex (MTBC) known as causative agents of human tuberculosis. Tuberculosis infection is one of the most important occupational risks for healthcare workers (HCWs) in most countries, such as Iran. In general, there are two types of tuberculosis, they include: latent infection and active TB. Latent tuberculosis infection (LTBI) means: a patient is infected with Mycobacterium tuberculosis but, the patient does not have active tuberculosis, clinical symptoms and radiological findings. According to studies, TB infection from patients to health care workers, depending on geographic region and economic situation is two to five times more than general population. The lowest incidence and the highest rates of LTBI prevalence among HCWs were 7% in Mashhad and 82.8% in Zahedan respectively. The risk factor acquisition of TB infection was a significant relationship with certain hospital wards (lung disease unit, laboratory, etc.), Increasing age and duration of employment. And results of this study show that TB is a significant problem among HCWs in Iran. Infection control and personal protective measures with training programs to patients and HCW is required to reduce the occupational risk of TB. Early detection of Mycobacterium tuberculosis and prevention treatment in people with latent TB are key elements in control of tuberculosis. Until now, different methods for detection of latent tuberculosis infection has been introduced that are not gold standard none of them. However, the most important methods, tuberculin skin test and the tests that based on measuring the production of interferon gamma are recommended, but each one of them has advantages and disadvantages. However, in all the articles of the tuberculin skin test is used for screening and early diagnosis of latent tuberculosis infection. So, the aim of this study was to Incidence and prevalence of latent tuberculosis infection in health care workers and risk factors, advantages and disadvantages of each method for diagnosis of latent tuberculosis infection and evaluate different strategies for reducing the incidence of latent tuberculosis infection in health care workers.

Role of metalloproteinase matrix in development of cavity and diagnosis of pulmonary tuberculosis
Abbasali Niyazi , Shima Javanbakht , Nezar Ali Muolaie , Mohamad Kazem Momeni , Mosayeb Shahriyar , Mehdi Nourallahzadeh,
Volume 77, Issue 1 (4-2019)
Abstract
Background: Matrix metalloproteases (MMPs) are multi-chain proteins that regulated by tissue inhibitor of metalloproteinases (TIMP) and several other mechanisms. This Includes transcription regulation and protein form secretion. The roles of MMPs in wound healing and tissue repair. In tuberculosis (TB), the activity of MMPs is increased and TIMP inhibitors decrease activity. Therefore, in tuberculosis, MMPs cause excessive damage to the lung tissue and cavity formation.
Methods: In a case-control study, plasma samples of healthy controls, symptomatic respiratory tract controls and tuberculosis patients were evaluated by available sampling in Ali Ibn Abitaleb and Bouali Hospitals, Zahedan, Iran, from Apri1 2015 to April 2018. Patients were divided into two groups: tuberculosis and control group and the level of MMPs were measured by the enzyme-linked immunosorbent assay (ELISA) method in plasma samples of the two groups. For MMP-8, which was important in the diagnosis of tuberculosis, a cutoff point was obtained.
Results: 384 people including 123 healthy controls. 107 non-tuberculosis, and 154 tuberculosis patients were examined; 230 patients in the control group and 154 patients in the tuberculosis group. Levels of MMPs in tuberculosis and symptomatic respiratory group were higher than healthy group. The mean of MMP-8 was significantly different between two groups (P<0.001). In this study, sensitivity, specificity, positive and negative predictive value of plasma MMP-8 in detection of TB in non-TB patients in MMP-8 cutoff point=6650 pg/ml were 65.4%, 78.2%, 50%, and 93% respectively outcome. Significantly, the rate of pulmonary cavity was significantly higher in the TB group; Higher cavity, higher concentration of plasma MMPs.
Conclusion: In this study, first comprehensive analysis of MMPs was performed. Two collagenases, MMP-1 and MMP-8, were active in tuberculosis, but MMP-8 was specifically higher in tuberculosis than in both symptomatic and healthy controls. Level of MMP-1, 3, 8, 9 was higher in men than in women. The analysis of genders separately showed MMP-8 was increased in tuberculosis group in comparison with control group and MMP-1 group in both TB and symptomatic respiratory tract increased.

Comparison of sensitivity and specificity of PCR and sputum smear compared to culture in diagnosis of tuberculosis
Marzieh Kazerani , Nahid Jalalian Elahi , Najmeh Mohajeri , Kiarash Ghazvini , Sara Taghdisi , Mohmadreza Ghafghazi , Mahdieh Motaghi , Mahdieh Motaghi ,
Volume 77, Issue 7 (10-2019)
Abstract
Background: Molecular detection has recently been proposed by nucleic acid amplification, known as polymerase chain reaction (PCR). The aim of this study was to compare the diagnostic method of smear and polymerase chain reaction with culture in terms of sensitivity, specificity, positive and negative predictive value in the diagnosis of pulmonary tuberculosis.
Methods: In this cross-sectional study, sputum samples were collected from 58 patients with suspected pulmonary tuberculosis referred to Ghaem Hospital in Mashhad from the beginning of April 2017 to the end of March 2018. The samples were delivered to the laboratory in less than 72 hours. Patients were sampled for three times. Bronchoscopy and Broncho alveolar lavage were performed in patients who were unable to produce sputum. The smear test was reported by Ghaem’s Laboratory after 24 hours. In our study, the culture method was considered as the gold standard and the sensitivity and specificity of the PCR methods and smear were compared with it.
Results: Patients ranged in age from 18 to 89 years. Among 58 suspected pulmonary tuberculosis, the method of cultivation confirmed the presence of the disease in 25 cases (43.1%). However, with smear, the presence of the disease has been proved in 27 patients (46.6%) and with the method of PCR in 24 patients was (41.4%). Sensitivity of smear in the diagnosis of pulmonary tuberculosis was (100%), and its specificity was 93.9%, the positive predictive value of this test was (92.6%) and the negative predictive value was (100.0%). The sensitivity of the PCR method in diagnosis of pulmonary tuberculosis was 88.0% and its specificity was 93.9%. The positive predictive value of this was (91.7%) and the negative predictive value was (91.2%).
Conclusion: In this study, between the two methods of smear and polymerase chain reaction, the acid fast smear method was more sensitive to the diagnosis of pulmonary tuberculosis than the polymerase chain reaction and the specificity of both methods were the same.

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