Antibiofilm and antivirulence potential of silver nanoparticles against multidrug-resistant Acinetobacter baumannii

Abstract

We aimed to isolate Acinetobacter baumannii (A. baumannii) from wound infections, determine their resistance and virulence profile, and assess the impact of Silver nanoparticles (AgNPs) on the bacterial growth, virulence and biofilm-related gene expression. AgNPs were synthesized and characterized using TEM, XRD and FTIR spectroscopy. A. baumannii (n = 200) were isolated and identified. Resistance pattern was determined and virulence genes (afa/draBC, cnf1, cnf2, csgA, cvaC, fimH, fyuA, ibeA, iutA, kpsMT II, PAI, papC, PapG II, III, sfa/focDE and traT) were screened using PCR. Biofilm formation was evaluated using Microtiter plate method. Then, the antimicrobial activity of AgNPs was evaluated by the well-diffusion method, growth kinetics and MIC determination. Inhibition of biofilm formation and the ability to disperse biofilms in exposure to AgNPs were evaluated. The effect of AgNPs on the expression of virulence and biofilm-related genes (bap, OmpA, abaI, csuA/B, A1S_2091, A1S_1510, A1S_0690, A1S_0114) were estimated using QRT-PCR. In vitro infection model for analyzing the antibacterial activity of AgNPs was done using a co-culture infection model of A. baumannii with human fibroblast skin cell line HFF-1 or Vero cell lines. A. baumannii had high level of resistance to antibiotics. Most of the isolates harbored the fimH, afa/draBC, cnf1, csgA and cnf2, and the majority of A. baumannii produced strong biofilms. AgNPs inhibited the growth of A. baumannii efficiently with MIC ranging from 4 to 25 µg/ml. A. baumannii showed a reduced growth rate in the presence of AgNPs. The inhibitory activity and the anti-biofilm activity of AgNPs were more pronounced against the weak biofilm producers. Moreover, AgNPs decreased the expression of kpsMII , afa/draBC,bap, OmpA, and csuA/B genes. The in vitro infection model revealed a significant antibacterial activity of AgNPs against extracellular and intracellular A. baumannii. AgNPs highly interrupted bacterial multiplication and biofilm formation. AgNPs downregulated the transcription level of important virulence and biofilm-related genes. Our findings provide an additional step towards understanding the mechanisms by which sliver nanoparticles interfere with the microbial spread and persistence.

Tailoring of Novel Azithromycin-Loaded Zinc Oxide Nanoparticles for Wound Healing

“…Agar was removed from the wells and AZM, ZnO, AZM-ZnONPs, and saline solution (negative control) were added to the formed wells. Plates were incubated at 37 • C overnight and the diameters of the inhibition zones were recorded [46,47].…”

Antibacterial, Antibiofilm and Anti-Virulence Activity of Biactive Fractions from Mucus Secretion of Giant African Snail Achatina fulica against Staphylococcus aureus Strains

“…To our knowledge, this is the first report of antibiofilm and anti-virulence effect of the mucus from A. fulica . Although in recent years, different studies have showed evidence of inhibition of virulence factors and biofilm formation of S. aureus strains, those were carried out with different compounds and natural products such as essential oils, antimicrobial peptides and nanoparticles [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ], but not with gastropod mucus secretions.…”

Antibiotics Combinations and Chitosan Nanoparticles for Combating Multidrug Resistance Acinetobacter baumannii

“…The obtained results were in accordance with many recent studies conducted in 2021 on the antimicrobial activities of different nanoparticles either alone or in combination with other antimicrobials have proved activity against various pathogens. These included, Casein-silver NPs combined with TGC against A. baumannii , 72 antibiofilm and anti-virulence potential of silver NPs against MDR A. baumannii , 73 Cu:Ag bimetallic NPs for antibiotic-resistant bacteria, 74 Lignin-Capped silver NPs, 75 Smaller Copper Oxide Nanoparticles against MDR Bacteria, 76 colistin-integrated chitosan nanoparticles. 77 Our results revealed that CNPs when combined with MEM significantly increased the susceptibilities of the MDR A. baumannii isolates by 100% as compared to MEM alone.…”