Showing 5 results for Mycobacterium Tuberculosis
Aliasghar Farazi, – Mansoureh Jabbariasl, Masoomeh Sofian,
Volume 15, Issue 1 (4-2012)
Abstract
Background: Nowadays, one of the basic problems of tuberculosis treatment is drug resistance. This study was done to determine the drug resistance of mycobacterium strains isolated from patients with pulmonary tuberculosis to anti-tuberculosis drugs and determine the affecting factors.
Materials and Methods: In a cross-sectional study, all patients with tuberculosis who were covered by Markazi Province Health Center (917 persons) during 2005 to 2010 were included in this study. For all patients with resistant pulmonary tuberculosis, culture and antibiogram by standard method (proportional) were done. Effective factors in drug resistance were identified by logistic regression model using SPSS software.
Results: Overall, the rate of resistance in patients with smear-positive was 7.3% and the rate of MDR-TB was equivalent to 4.3%, and 0.5% of smear positive patients were resistant to all five drugs. The most resistant strains were isoniazid (68.8%), rifampin (62.5%), pyrazinamide (25%), ethambutol (21.9%), and streptomycin (21.9%), respectively. The highest rate of resistance was in the 15-45 years age group. The incidence of resistance was significantly associated with sex, grade of smear positivity, relapse of TB, and HIV infection.
Conclusion: The study of drug resistant mycobacterium strains over six years showed a growing trend. Therefore, close attention to prevent the production and dissemination of resistant strains is very essential.
Arezo Eshghinejad, Aliasghar Farazi, Babak Eshrati, Hamid Khalili, Mana Shojapour, Aazam Ahmadi, Mohamad Arjmandzadegan,
Volume 15, Issue 5 (10-2012)
Abstract
Background: Differentiation of M. tuberculosis complex organisms were assigned to one of three genotypic groups based on the combinations of polymorphisms at katG codon 463 and gyrA codon 95. Early identification of strains belonging to any particular group is very important. This study was planned to identify major genetic groups of clinically isolated Mycobacterium tuberculosis. Materials and Methods: In this cross sectional study 33 sputum samples were collected from tuberculosis patients of the Markazi province. DNA purification from isolated samples was performed by Chelex 100. Identification of isolates was confirmed by detection of katG gene and the mutation in KatG463 by using PCR method and RFLP respectively. Finally 620-bp of katG gene and 194-bp of gyrA gene purified from PCR product were sequenced. Results: Amplification of 620-bp fragment of katG gene was a good way to confirm the detection of bacteria as a molecular approach. Results of sequencing codon GyrA95 in combination by results of PCR-RFLP determined type of the major genetic group (MGG). Therefore it showed that among the 33 Mycobacterium tuberculosis isolates 12 samples were MGG 1, 15 Samples were MGG2 and 6 samples were MGG 3. Results revealed that MGG 2 was dominant form of M. tuberculosis strains of Markazi province by frequency of 45.5%. Conclusion: Based on the results of this study MGG2 occurrence was more frequent among clinical strains in Markazi province that its accordance with susceptibility of these strains to conventional antibiotics is notable. In this study, three applicable benefits from the test as: MGG typing, molecular detection of M. tuberculosis and bacterial resistance to Isoniazid were proven.
Behnam Rafiee, Nader Mosavari, Ali Asghar Farazi, Razie Nazari, Rouholah Keshavarz, Keyvan Tadayon,
Volume 15, Issue 6 (11-2012)
Abstract
Background: Tuberculosis is an old problem that is currently considered a great challenge. Noticing Iran’s borders with Afghanistan and Pakistan, which are among the 22 high burden countries around the world, the present study was conducted to analyze the current molecular epidemiology of TB and survey genetic diversity of Mycobacterium tuberculosis strains in Markazi province, Iran. Materials and Methods: In this experimental study, 57 sputum specimens from smear positive patients admitted to health centers in Markazi province were cultured on specific mycobacterial culture media. Genomic DNA was extracted by standard protocols of WHO and digested separately by PvuII and AluI. Electrophoresis was performed and DNA fragments were transferred to positively charged nylon membrane by southern blotting method and hybridization by PGRS probe. The hybridized strains were subsequently detected by enzymatic reaction and analyzed. Results: Genotyping of the isolates by PGRS-RFLP with Pvu II and AluI displayed a wide range of genetic diversity so that 50 and 45 genotypes were identified, respectively. Conclusion: Noticing the great diversity of PGRS in the Mycobacterium tuberculosis strains, it can be concluded that in the study population, the majority of the patients hadtuberculosis with different etiologies. Therefore, it seems that reactivation of latent infection has had the main role in the spread of tuberculosis
Behnaz Taheri, Siyamak Samiee, Mehdi Paryan, Ehsanollah Ghaznavi-Rad,
Volume 16, Issue 5 (8-2013)
Abstract
Background: The emergence of drug-resistant strain of M.tuberculosis is one of the most critical issues facing TB researchers and clinicians. Rapid diagnosis of drug-resistant tuberculosis is essential for the prompt initiation of effective second-line therapy to improve treatment outcome and limit transmission of this obstinate disease. The aim of this study is to develop a Real-time PCR assay for the detection of mutations in RRDR (rifampcin resistance determinant region) of rpoB which conferring rifampicin resistance in Mycobacterium tuberculosis.
Materials and Methods: In this experimental study, the primer and probe set were designed for a RRDR region of rpoB gene using a specialized software. Clinical specimens that had previously been evaluated resistant or sensitive by using convential method, were used for assessing the clinical sensitivity and specificity of the assay.
Results: The clinical sensitivity of the assay was determined 100%. The primers and the probes were rpoB specific and no cross-reaction was observed with other microorganisms and human genome bioinformatically. The clinical specificity of developed Real-time PCR assay was examined experimentally using 25 negative samples and determined to be 100%.
Conclusion: The developed real-time PCR assay can be used as an appropriate and efficient tool for the rapid detection of rifampicin-resistant Mycobacterium tuberculosis.
Ali Reza Morad Abadi, Mohammad Arjomandzadegan, Navid Emami, Manijeh Kahbazi, Azam Ahmadi, Saeed Falahat, Seyyed Hossein Hosseini, Mehdi Kargaran, Parisa Khosravi,
Volume 21, Issue 4 (8-2018)
Abstract
Background and Aim: Ziehl Nelson staining, fluorescent and also culture are the standard methods for the diagnosis of tuberculosis. In this study, the performance of conventional cultivation methods was compared with Flash PCR.
Materials and Methods: A total of 56 sputum samples from patients with suspected tuberculosis in Tuberculosis Center of Arak city were collected and Ziehl–Neelsen and culture in Löwenstein–Jensen medium were accomplished. Moreover, DNA from all of the 56 sputum samples was extracted by Chelex100 method. Molecular evaluation was accomplished by Flash PCR kit containing probes and primers for gene amplification IS6110. Positive and negative controls together with samples were used in a MTC410 apparatus for amplification. FD-12 apparatus was used to evaluate the results. In addition, electrophoresis on agarose was used for confirmation of the results.
Findings: From 56 sputum samples of suspected TB patients, 20 samples were positive and 36 samples were negative on microscopic evaluation and culture methods. FLASH-PCR molecular analysis showed that all of 20 positive samples were positive in molecular methods, too. On the other hand, three of sputum samples that were negative by culture and staining were positive in FLASH-PCR method. One of these 3 patients, received Isoniazid, pyrazinamide and ethambutol antibiotic by responsible medicine. All results were confirmed using conventional electrophoresis.
Conclusion: In some negative samples, possibly because of the small number of bacteria in sample or a defect in the sampling, the Flash PCR may due good advantages. Therefore, due to the low cost, this method is recommended for routine use.
