Study of Moxifloxacin and Silver Nanoparticle Composite Efficacy on pre-XDR Mycobacterium Tuberculosis Strains

<b>Introduction:</b> Susceptibility testing of new and repurposed anti-TB drugs in Georgia in 2020 demonstrated that, 28% of pre-XDR-TB cases had additional resistance to one of the most effective “Group A” drugs. <b>The aim:</b> of the study was to investigate in vitro inhibitory effect of Moxifloxacin (Mfx) and silver nanoparticle (AgNPs ) composite on Mfx&nbsp; resistant ( Mfx/R-TB) Mycobacterium tuberculosis&nbsp; (MTB) strains. <b>Materials and Methods:</b> Standard dose of Mfx&nbsp; and 20 nm AgNPs [of 6 different concentrations: 0.25%; 0.5%; 1%; 2.5%; 5%; 10%] were added to already grown 40 resistant Mfx/R-TB cultures. The control group consisted of 35 Mfx/R isolates, to which only solutions of AgNPs of identical concentrations were added. The inhibitory effect of different concentrations of Mfx&nbsp; and AgNPs was evaluated according to MTB growth rate using the BACTECTM MGIT 960TM TB System. <b>Results:</b> In vitro usage of nanocomposite with&nbsp; standard dose of Mfx and 20 nm&nbsp; 2.5% AgNPs&nbsp; solution showed minimal inhibitory effect on Mfx/R-MTB strains, while using&nbsp; with standard dose of Mfx or solely, and usage of&nbsp; 5,0% solution demonstrated minimal bactericidal effect.&nbsp; In vitro usage of standard dose of Mfx with addition of 20 nm&nbsp; 2.5% AgNPs nanocomposite solution increased minimal inhibitory effect by 16.7% on Mfx/R-MTB strains (86.7%) compared to using only 20 nm&nbsp; 2.5% solution of AgNPs (70%). <b>Conclusion:</b> The study of the effectiveness of the nanocomposite on pre-XDR MTB strains in vitro showed potential influence of AgNPs on overcoming resistance against Mfx.