In-vivo and In-vitro Anti-Acinetobacter baumannii Activity of Citrate-Capped Silver Nanoparticles

Ibtesam Ghadban Auda, Istabreq Mohamed Ali Salman, Dalal Abed Al-Sattar, Jameelah Ghadban Oduha



Silver nanoparticles (Ag NPs) are of potential interest because of their effective antibacterial and antiviral activities. Capping agents are used for exhibiting a better antibacterial activity than uncapped Ag NPs. There are very few reports that have shown the usage of Ag NPs for in-vivo antibacterial therapy. Citrate-capped silver nanoparticles were synthesized chemically by citrate reduction method; the size of Cit-Ag NPs was determined by an atomic force microscope (AFM) and was between 15 - 90 nm. Acinetobacter baumannii (A. baumannii) isolates were the only sensitive species to Cit-Ag NPs. MICs and MBC of Cit-Ag NPs were determined by using A. baumannii. The results showed an additive effect of Cit-Ag NPs. Four mice groups were infected with a sub-lethal dose of A. baumannii intraperitoneally, IP. The single daily dose of Cit-Ag NPs and imipenem plus Cit-Ag NPs combination were administered IP. Imipenem and phosphate buffer saline (PBS) was used as positive control and negative control, respectively. Interestingly, only the PBS-treated group showed growth of A. baumannii in the liver and spleen of sacrificed mice. Histopathologically, Cit-Ag NPs showed antibacterial activity and had an additive effect when combined with imipenem in vivo and in vitro. Moreover, the Cit-Ag NPs showed dose-dependent activity and the organs differed in the illumination of the toxicity effect of Cit-Ag NPs even after high dose administration. In conclusion, Cit-capped Ag NPs had antibacterial activity against multiple drug resistant (MDR) A. baumannii but not against K. pneumoniae and E. coli. Cit-capped Ag NPs increased the inhibition zone of imipenem in additive effect; the minimum inhibitory concentration and the minimum bactericidal concentration of Cit-capped Ag NPs were relatively low. Cit-capped Ag NPs eliminated A. baumannii infection in vivo when it was given alone or in combination with imipenem. The cytotoxicity of Cit-Ag NPs was dose-dependent and the organs differed in the illumination of the inflammatory effect of Cit-Ag NPs after high dose administration. It is not recommended to use Cit-capped Ag NPs systemically despite their valuable additive antibacterial effect especially with a high dose and the combination with imipenem, Topical administration needs to be evaluated.

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Nano Biomedicine and Engineering.

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