Inhibitory effect of the Nth gene on drug resistance in Mycobacterium tuberculosis

Abstract

To clarify the role of Nth gene in drug resistance of Mycobacterium tuberculosis (MTB), the clinical strain MTB were isolated and cultured from the sputum of pulmonary tuberculosis patients, and grouped according to the results of drug sensitivity tests. The expression levels of Nth mRNA and protein were detected by Polymerase chain reaction and Western blot, respectively. The bacteriophage-mediated homologous recombination gene knockout method and seamless cloning and ligation technology were used to knockout Nth gene and perform backfill overexpression experiments on MTB standard strain H37Rv. The resistance of the obtained strains was induced, and its growth was compared. In the results, the resistance rate of 193 clinical isolates to first-line drugs was 37.37%. The expression levels of Nth mRNA and protein in sensitive strains were higher than those in drug-resistant strains (P < 0.05). Strains without Nth were more likely to grow, while the growth of the Nthoverexpressing strain was inhibited. When two drugs are used in combination, the bacteria developed drug resistance later than those induced by single drug. In conclusion, the Nth gene has an inhibitory effect on the drug resistance of MTB.