The frequency of point mutations associated with resistance to isoniazid and rifampin among clinical isolates of multidrug-resistant Mycobacterium tuberculosis in the west of Iran

Molecular characterization of genetic mutations with fitness loss in pulmonary tuberculosis patients associated with HIV co-infection in Northwest Amhara, Ethiopia

“… 32 The KatG S315T1 substitution (100%) was the most frequent specific variant that caused high-level INH resistance in our study. This finding aligns with the previous studies that identified the S315T1 variant as the most common genetic variation in the katG gene in Northwest Ethiopia (70.6%) 6 and (87.8%), 7 Addis Ababa Ethiopia (76.9%), 5 Iran (70%), 35 India (86.3%), 9 China (73.8%), 37 Burkina Faso (77.3%), 33 and Pakistan (78.2%) 32 ; but higher S315T1 mutation reported in Eastern Ethiopia (91.8%), 34 Addis Ababa Ethiopia (100%), 30 India (96.2%), 13 central Africa Republic (94.2%), 36 and Mongolia (99.1%) 42 ; and lower proportions of S315T1 -specific mutations were observed in Northeastern Ethiopia (25%), 4 China (62.9%), 12 Iran (32%), 43 and Pakistan (69.8%). 2 A specific C-15T mutation in the inhA regulatory region was detected in a higher proportion of 100% in our study, which is consistent with previously reported results in Eastern Ethiopia (100), 34 Mongolia (98.0%), 42 and India (88.9%) 9 ; however, lower rates were detected in Northwest Ethiopia (41%) 6 and (3.3%), 7 Addis Ababa Ethiopia (30.8%), 5 Tigray region of Ethiopia (5%), 31 China (5.7%) 12 and (24.6%), 37 South Africa (13.4%), 41 and Pakistan (14.9%) 32 and (5.6%).…”

“…The most common genetic variant in the rpoB gene associated with high levels of resistance to RIF was found to be at codon S450L (55.6%), followed by H445Y and D435V (22.2%). Our findings in S450L are consistent with the high rates reported in other studies across various regions such as Eastern Ethiopia (59.1%), 34 Northwest Ethiopia (64.0%), 7 Iran (66%), 35 the Central Africa Republic (53.4%), 36 Pakistan (55.6%) 32 and (64.1%), 2 India (58.8%), 9 and China (62.5%) 12 and (58.2%). 37 By contrast, the frequency of mutation at codon S450L in our study was higher than the previous report from Iran (40%) 38 and China (31.25%) 39 but lower than studies conducted in the Tigray region of Ethiopia (70%), 31 Addis Ababa Ethiopia (81.3%), 30 and Pakistan (85%).…”

“…One more finding in our study, the MTBDRplus LPA assay exhibited a high sensitivity of 91.7% and a specificity of 99.3% for detecting RIF resistance, which is comparable with results reported in earlier studies in Northeastern Ethiopia (100% and 98.3%), 4 China (98.7% and 88.9%), 37 Pakistan (98.8% and 92.9%), 32 and Iran (91% and 100%) 35 ; while there was a higher sensitivity than from Northwest Ethiopia (75.0% and 100%) 6 and higher specificity than from South Africa (95% and 75%). 46 This difference in sensitivity might be due to variations in sample size and the presence of strains that carried mutations outside the 81-bp hotspot region or in the amino-terminal end of the rpoB gene that was not detected by LPA strips in detecting RIF resistance.…”

Patterns and profiles of drug resistance-conferring mutations in Mycobacterium tuberculosis genotypes isolated from tuberculosis-suspected attendees of spiritual holy water sites in Northwest Ethiopia

“…The gene mutation at codon S531L was noted as the dominant mutation of the rpo B gene responsible for RIF resistance in several previous studies done in different parts of Ethiopia; which includes the Amhara region (73%) ( 46 ), Tigray region (70%) ( 44 ), Somali region (80%) ( 47 ), Addis Ababa (81.3%) ( 48 ), Southwest Ethiopia (82.4%) ( 49 ), a meta-analysis report, Ethiopia (74.2%) ( 21 ), and a recent multicenter study report, Ethiopia (59.1%) ( 45 ). In line with our result, a higher frequency of mutation at codon S531L was reported in other high TB burden countries like China (58%) ( 50 ), India (62%) ( 51 ), Pakistan (64%) ( 52 ), Sudan (64%) ( 53 ), and Iran (66%) ( 54 ). The other mutation in our study, His526Tyr was previously reported in Ethiopia, which ranged from 6.6–17.2% ( 21 , 44 , 45 , 55 ), Sudan (12.8%) ( 53 ), India (11.1%) ( 51 ), and China (8.9%) ( 50 ).…”

Drug resistance and the genotypic characteristics of rpoB and katG in rifampicin- and/or isoniazid-resistant Mycobacterium tuberculosis isolates in central Vietnam

“…In other research, 104 RIF-resistant isolates had mutations in the 81bp RRDR of the rpoB gene; the most prevalent mutations were at codons 531 (43%), 526 (31%), and 516 (15%) [ 32 − 34 ]. In the west of Iran, a study by Hamed et al [ 35 ] found 32 MDR isolates among 54 M. tuberculosis samples, while the other 22 isolates were INH and RIF sensitive. Among the 32 MDR isolates, 22 strains (70%) had katG codon 315 mutations, 1 strain (3%) had inhA mutations, and 9 strains (28%) had no mutations at all.…”