A Preliminary Study on the Synergistic Effect of Nano Ag and Anti-Tuberculosis Drugs on Drug-Resistant Mycobacterium tuberculosis

Abstract

To determine the bactericidal effect of nano silver and anti-tuberculosis drugs on drug-resistant Mycobacterium tuberculosis. Solid-state drug sensitivity tests with streptomycin (SM), isoniazid (INH), RIF, EMB, kanamycin (km), and ofloxacin (ofx) were carried out on H37Rv and different clinical isolates. Briefly, the effects of SM, INH, RIF, EMB (1.0 μg/mL, 0.1 μg/mL, 1.0 μg/mL, 5.0 μg/mL), and anti-tuberculosis drugs, and their combined effect with 0.15 μg/mL and 0.30 μg/mL nano silver on drug-resistant tuberculosis bacteria were evaluated by liquid drug sensitivity test. At the low concentration (0.15 μg/mL), nano silver could not effectively kill the tuberculosis strains; however, at concentrations ≥0.30 μg/mL, it could effectively kill H37Rv and the clinical isolates of the sensitive, single-resistant, multi-resistant, multi-resistant, and extensively resistant strains. Combining 0.15 μg/mL nano silver with the four first-line anti-tuberculosis drugs could not effectively kill the tuberculosis strains; however, combining 0.30 μg/mL nano silver and the anti-tuberculosis drugs could effectively kill the drug-resistant tuberculosis strains. Nano silver exhibits a concentrationdependent killing effect on tubercle bacillus. Further, a nano silver concentration higher than 0.30 μg/mL could kill sensitive and resistant tubercle bacillus.