Showing 3 results for Mycobacterium Tuberculosis
Hossein Goodarzi, Elnazossadat Mirsamadi, Parisa Farnia, Somayeh Jahani Sherafat,
Volume 34, Issue 2 (7-2010)
Abstract
Abstract
Background: The Beijing strain of Mycobacterium tuberculosis is responsible for more than 25% of cases of Tuberculosis in the world, it has a high transmission potential and there is a significant correlation between Beijing strain and multidrug resistance. In this study we compared the presence of Phospholipase C genes in Beijing and Nonbeijing strains of Mycobacterium tuberculosis.
Methods: CTAB method was used to extract DNA from positive culture specimens from patients with pulmonary tuberculosis. Spoligotyping was used to identify Beijing from non-Beijing strains. Presence of Phospholipase C genes was ascertained by using PCR.
Result: Of 200 specimens, 19 were Beijing strain, (9.5%) and 181 non Beijing strains, (90.5%). In Beijing strains, 16 specimens, (84.2%)were positive for plcA,17 (89.5%) were positive for plcB and 17 (89.5%) were positive for plcC genes and in non Beijing strains 17 specimens, (9.4% ), were positive for plcA, 18(9.9%), for plcB and 18(9.9%) for plcC.
Conclusion: Majority of Beijing strains have phospholipase C genes that may be responsible for the virulence of this strain.
Keywords: Phospholipase C, MDR, Beijing, Mycobacterium tuberculosis
Mr Amirhossein Akbari Aghababa, Mr Mohammad Javad Nasiri, Mr Parviz Pakzad, Mrs Elnaz Sadat Mirsamadi,
Volume 47, Issue 2 (7-2023)
Abstract
Background and Aim: Multidrug- resistant (MDR) tuberculosis (TB) is caused by a strain of Mycobacterium tuberculosis (MTB) that was at least resistant to isoniazid (INH) and rifampicin (RIF). World Health Organization reported 399,000-501,000 cases of RIF resistance and they reported this case without knowing about this situation in Tehran. So, it is an important concern.
Methods: Descriptive method and research was done on 1000 clinical samples of people suspected of tuberculosis. All the samples were studied in the TB center of the province for microscopic examination and culture. Using the ratio method, the drug sensitivity test to the first- line anti- tuberculosis drug was performed for positive MTB cultures on Löwenstein- Jensen (LJ) culture medium. All isolates resistant and sensitive to RIF were identified by GeneXpert and the prevalence of resistance in the samples was determined and its actual level in the community was estimated. Then, using SPSS software, the level of resistance and factors affecting it were checked.
Results: According to theprevalence in these samples in this research, out of 440 positive samples, 3 positive samples, or 0.07% were resistant.
Conclusion: It seems that resistance to rifampin is not a big problem and is not a cause for concern. As a result, the prevalence of drug resistance in this study area was relatively low. Our suggestion is to conduct more studies in different regions of this country to evaluate the efficiency of GeneXpert and whether it can be useful and effective in Iran.
Ms Hanieh Bagherifard, Dr Mitra Salehi, Dr Mona Ghazi,
Volume 47, Issue 4 (2-2024)
Abstract
Background and Aim: The emergence of drug resistance and treatment- renitent Mycobacterium tuberculosis has made controlling the disease a challenge. World Health Organization (WHO) estimates that approximately 500,000 new cases of tuberculosis occur annually. Considering that mechanisms involved in drug resistance are yet to be elucidated and results of the studies are not consistent, we decided to investigate the correlation between mutations in thyA gene and resistance to para- aminosalicylic acid (PAS).
Methods: In this descriptive cross- sectional study, a total of 255 positive MTB specimens were isolated during a three- year period using standard microscopic and culture methods from which 68 Multidrug resistant (MDR) and extensively drug resistant (XDR) tuberculosis samples were selected through drug susceptibility testing. Then, to determine potential mutations in thyA gene, the fragment was amplified using conventional PCR and products were sequenced. Afterward, mutations which have been induced amino acid substitutions were evaluated with various protein prediction tools. Also, the correlation between mutations and drug resistance was statistically determined using chi-square test.
Results: From 255 clinical TB samples, 68 (26.7%, CI 21.3%) MDR / or XDR-TB strains were isolated. In total, 13 (19.1%) were PAS- resistant and 5 (38.4%) of them had different nucleotide mutations in thyA gene. All of the mutations were statistically correlated with drug resistance. Moreover, the results of bioinformatics showed that identified mutations could lead to the structural and functional disruption of the protein.
Conclusion: According to our results, mutations in thyA gene have appeared to be associated with resistance to PAS. Also, our findings have shed light on the potential of the analysis of short genomic regions and new computational tools in unraveling the molecular mechanisms of drug resistance.
