Synergistic Antimicrobial Activity of Colistin and Amikacin with Zinc Oxide Nanoparticles and Their Posttranscriptional Regulation of <i>mcr-1</i> Gene Expression in Colistin-Resistant <i>Klebsiella pneumoniae</i>

The bacteria <i>Klebsiella pneumoniae</i> is encapsulated, rod-shaped, nonmotile, and Gram-negative bacilli. <i>K. pneumoniae</i> causes a variety of illnesses. They express various virulence factors such as capsules, which are primary virulence factors responsible for the pathogenicity and protection of bacteria from phagocytosis, lipopolysaccharide, which act as external membranes of the bacteria; and fimbriae-І and ІІІ which promote the binding to biological surfaces like medical devices such as ventilators. <i>K. pneumoniae</i>'s resistance to cephalosporins (3^rd and 4^th generation), quinolones, carbapenem, and colistin is increasing. Colistin is the last trait to treat multidrug-resistant <i>K. pneumoniae</i>. The monotherapy is becoming ineffective to treat infections. Plasmid-borne genes called <i>mcr-1</i> mediate colistin resistance, which is more prevalent. Colistin resistance and gene detection were done by using Epsilometry-test and conventional PCR, respectively. Amikacin was tested for synergism with colistin. Colistin with zinc oxide nanoparticle (NP) synergism was also tested. The properties of zinc oxide NPs are assessed by Fourier-transform infrared (FTIR), scanning electron microscope (SEM), and ultraviolet (UV) visible spectroscopy. Antibacterial activity of zinc oxide NPs was determined using the agar well diffusion method. In our study, we encourage combination drug therapy to treat the colistin-resistant <i>K. pneumoniae</i>. The synergistic activity of combined drugs was tested using checker-board technique. The results revealed that the synergistic activity of colistin combined with zinc oxide NPs and amikacin against colistin-resistant <i>K. pneumoniae</i> was found to be effective and can be further developed against the colistin resistant <i>K. pneumoniae</i>.