An In-Vitro Study of Molecular Effects of a Combination Treatment with Antibiotics and Nanofluid Containing Carbon Nanotubes on Klebsiella pneumonia

: We aimed to prepare a nanofluid, containing f-MWCNTs, and investigate the antibacterial efficacy of f-MWCNTs+ ciprofloxacin (cip) on Klebsiella pneumoniae by evaluating the virulence gene expression. Methods: This study was carried out from 2019 to 2020, in the Department of Mycobacteriology and Pulmo nary Research, Pasteur Institute of Iran. The nanofluid containing antibiotic and f-MWCNTs were prepared by the ultrasonic method. The minimum inhibitory concentrations (MICs) of ciprofloxacin and f-MWCNTs were determined using the broth micro dilution MIC tests. For examining the antibacterial effects, the expression level of virulence genes, under the influence of f-MWCNTs, was evaluated by a real-time PCR. Results: The effect of 8 µg/ml ciprofloxacin + 400 µg/ml f-MWCNTs, completely inhibited the growth of the resistant isolate of K. pneumoniae, while, in the ATCC 700,603 isolate, 2 µg/ml ciprofloxacin with 100 µg/ml f MWCNT could inhibit a bacterial growth. In the resistant K. pneumoniae clinical isolate, after f-MWCNT+cip treatment, the expression of fimA, fimD, wza, and wzi genes was significantly downregulated, compared to the ciprofloxacin treatment, and upregulated, compared to the negative control. For the ATCC 700,603 isolatetreated with f-MWCNT+cip, the expression of fimA, fimD and wza virulence genes showed upregulation, com pared to the negative control and downregulated in comparison with the ciprofloxacin treatment. Conclusion: Simultaneous treatment of resistant isolate of K. pneumoniae with f-MWCNTs +antibiotic could improve the effectiveness of antibiotic at lower doses, due to the reduced expression of virulence genes in comparison with antibiotic treatment, besides the increased cell wall permeability to antibiotics.