Nguyen Quang Huy, Nguyen Thi Van Anh, Bañuls Anne-Laure
LMI DRISA, Department of Life Sciences, University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam.
Department of Bacteriology, National Institute of Hygiene and Epidemiology (NIHE), Hanoi, Vietnam.
Trop Med Int Health. 2025 May;30(5):426-436. doi: 10.1111/tmi.14104. Epub 2025 Mar 13.
Vietnam is a hotspot for the emergence and spread of multidrug-resistant Mycobacterium tuberculosis. This study aimed to perform a retrospective study on the compensatory evolution in multidrug-resistant M. tuberculosis strains and the association with drug-resistant mutations and M. tuberculosis genotypes.
Hundred and seventy-three strains resistant to rifampicin (n = 126) and/or isoniazid (n = 170) (multidrug-resistant = 123) were selected according to different drug-resistant patterns and genotypes. The genes/promoter regions including rpoA, rpoB, rpoC, katG, inhA, inhA promoter, ahpC, ahpC promoter, gyrA, gyrB, and rrs were sequenced for each strain.
Frequency of rifampicin- and isoniazid-resistant mutations in multidrug-resistant strains was 99.2% and 97.0%, respectively. Mutations associated with low -high levels of drug resistance with low- or no-fitness costs compared to the wild type, including rpoB_Ser450Leu, katG_Ser315Thr, inhA-15(A-T), gyrA_Asp94Gly, and rrs_A1401GA, accounted for 46.3%, 76.4%, 16.2%, 8.9%, and 11.4%, respectively, in the multidrug-resistant strains. Beijing and Euro-American genotype strains were associated with high-level drug-resistant mutations, rpoB_Ser450Leu, katG_Ser315Thr, and gyrA_Asp94Gly, while East African-Indian genotype strains were associated with low to high-level drug-resistant mutations, rpoB_His445Asp, rpoB_His445Tyr, inhA-15(C-T) and rrs_A1401G. Multidrug-resistant strains (19.5%) harboured compensatory mutations linked to rifampicin resistance in rpoA, rpoB, or rpoC. Notably, the frequency of compensatory mutations in Beijing genotypes was significantly higher than in East African-Indian genotypes (21.1% vs. 3.3%, OR = 7.7; 95% CI = 1.0 to 61.2, p = 0.03). The proportion of multidrug-resistant strains with rpoB_Ser450Leu mutations carrying rpoA-rpoC mutations was higher than that of strains with other rpoB mutations (OR = 5.4; 95% CI = 1.4 to 21.1, p = 0.02) and was associated with Beijing strains. Only 1.2% (2/170) isoniazid-resistant strains carried aphC-52(C-T) mutation in the promoter region of the ahpC gene, which was hypothesised to be the compensatory mutation in isoniazid-resistant strains. Meanwhile, 11 isoniazid-resistant strains carried a katG mutation combined with either inhA-8(T-C) or inhA-15(A-T) mutations and were associated with East African-Indian strains.
Mutations associated with high levels of drug resistance without/with low fitness costs (rpoB_Ser450Leu and katG_Ser315Thr) along with compensatory mutations linked to rifampicin resistance were strongly associated with multidrug-resistant M. tuberculosis Beijing strains in Vietnam.
越南是耐多药结核分枝杆菌出现和传播的热点地区。本研究旨在对耐多药结核分枝杆菌菌株的补偿进化及其与耐药突变和结核分枝杆菌基因型的关联进行回顾性研究。
根据不同的耐药模式和基因型，选择了173株对利福平（n = 126）和/或异烟肼（n = 170）耐药（耐多药 = 123）的菌株。对每个菌株的rpoA、rpoB、rpoC、katG、inhA、inhA启动子、ahpC、ahpC启动子、gyrA、gyrB和rrs等基因/启动子区域进行测序。
耐多药菌株中利福平和异烟肼耐药突变的频率分别为99.2%和97.0%。与野生型相比，与低-高水平耐药相关且适应度成本低或无适应度成本的突变，包括rpoB_Ser450Leu、katG_Ser315Thr、inhA-15(A-T)、gyrA_Asp94Gly和rrs_A1401GA，在耐多药菌株中的占比分别为46.3%、76.4%、16.2%、8.9%和11.4%。北京基因型和欧美基因型菌株与高水平耐药突变rpoB_Ser450Leu、katG_Ser315Thr和gyrA_Asp94Gly相关，而东非-印度基因型菌株与低-高水平耐药突变rpoB_His445Asp、rpoB_His445Tyr、inhA-15(C-T)和rrs_A1401G相关。耐多药菌株（19.5%）在rpoA、rpoB或rpoC中存在与利福平耐药相关的补偿性突变。值得注意的是，北京基因型中补偿性突变的频率显著高于东非-印度基因型（21.1%对3.3%，OR = 7.7；95%CI = 1.0至61.2，p = 0.03）。携带rpoB_Ser450Leu突变并伴有rpoA-rpoC突变的耐多药菌株比例高于携带其他rpoB突变的菌株（OR = 5.4；95%CI = 1.4至21.1，p = 0.02），且与北京菌株相关。仅1.2%（2/170）的异烟肼耐药菌株在ahpC基因启动子区域携带aphC-52(C-T)突变，推测该突变是异烟肼耐药菌株中的补偿性突变。同时，11株异烟肼耐药菌株携带katG突变并伴有inhA-8(T-C)或inhA-15(A-T)突变，且与东非-印度菌株相关。
与高水平耐药相关且无/低适应度成本的突变（rpoB_Ser450Leu和katG_Ser315Thr）以及与利福平耐药相关的补偿性突变与越南耐多药结核分枝杆菌北京菌株密切相关。
