Investigation into the impact of Rv2048c gene knockout on the drug susceptibility of Mycobacterium tuberculosis

doi:10.19982/j.issn.1000-6621.20250429

Abstract

Abstract:

Objective: To investigate the effect of Rv2048c gene knockout on the drug susceptibility of Mycobacterium tuberculosis (MTB). Methods: In this study, the MTB standard strain (H37Rv-WT) was used as a template to construct the Rv2048c gene knockout strain (H37RvΔRv2048c) via homologous recombination principle. Colony morphology, cell size, and cell wall integrity were evaluated through solid culture, acid-fast staining, and scanning electron microscopy. A growth curve was plotted to evaluate the growth rate. The minimum inhibitory concentration (MIC) was determined using the microplate method for drug susceptibility testing. Cell wall permeability was assessed using ethidium bromide staining. The biological characteristics, anti-tuberculosis drug susceptibility, and cell wall permeability of H37Rv-WT and H37RvΔRv2048c were systematically compared. Subsequently, the influence of the Rv2048c gene on MTB drug susceptibility and its potential mechanism were analyzed. Results: H37RvΔRv2048c was successfully constructed. Colony morphology transitioned from the rough type (R type) in H37RV-WT to the smooth type (S type) in H37RvΔRv2048c. Both strains exhibited rod-like structures with comparable cell wall compositions; however, the bacterial length of H37RvΔRv2048c was significantly shorter. The MIC of ethionamide (Eto) against H37RvΔRv2048c (1.25 μg/ml) was 1/4 of the MIC of Eto against H37Rv-WT (5.00 μg/ml); the MIC of amikacin (Am) against H37RvΔRv2048c (0.25 μg/ml) was 1/4 of the MIC of Am against H37Rv-WT (1.00 μg/ml). After ethidium bromide staining, the fluorescence intensity of H37RvΔRv2048c (1.526 RFU) was significantly higher than that of H37Rv-WT (0.924 RFU)(t=16.960, P<0.001). Conclusion: Deletion of the Rv2048c gene results in reduced MIC values for Eto and Am. This gene may modulate MTB susceptibility to Eto and Am by altering cell wall permeability. This study provides new insights into MTB drug resistance mechanisms and identifies potential targets for enhancing the effectiveness of Eto and Am.

Key words: Mycobacterium tuberculosis, Knockout, Microbial sensitivity tests, Research

CLC Number:

R521

Li Nana, Wang Hong, Tian Peng, Wen Jixiu, Yang Dan, Wu Xia, Lan Yuanbo. Investigation into the impact of Rv2048c gene knockout on the drug susceptibility of Mycobacterium tuberculosis[J]. Chinese Journal of Antituberculosis, 2025, 47(12): 1621-1628. doi: 10.19982/j.issn.1000-6621.20250429

Figures/Tables 6

References 20

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药物类别	MIC(μg/ml)
药物类别	H37Rv-WT	H37RvΔRv2048c
氧氟沙星	0.25	0.25
莫西沙星	<0.06	<0.06
利福平	<0.12	<0.12
阿米卡星	0.50	<0.12
链霉素	0.50	<0.25
利福布汀	<0.12	<0.12
对氨基水杨酸	0.50	0.50
乙硫异烟胺	20.00	0.60
环丝氨酸	4.00	4.00
异烟肼	0.06	<0.03
卡那霉素	1.20	<0.60
乙胺丁醇	1.00	<0.50