Biogenic silver nanoparticle (Bio‐AgNP) has an antibacterial effect against carbapenem‐resistant Acinetobacter baumannii with synergism and additivity when combined with polymyxin B

Abstract

Aims: Carbapenem-resistant Acinetobacter baumannii represents a public health problem, and the search for new antibacterial drugs has become a priority. Here, we investigate the antibacterial activity of biogenic silver nanoparticles (Bio-AgNPs) synthesized by Fusarium oxysporum, used alone or in combination with polymyxin B against carbapenem-resistant A. baumannii. Methods and Results:In this study, ATCC ® 19606 ™ strain and four carbapenemresistant A. baumannii strains were used. The antibacterial activity of Bio-AgNPs and its synergism with polymyxin B were determined using broth microdilution, checkboard methods and time-kill assays. The integrity of the bacterial cell membrane was monitored by protein leakage assay. In addition, the cytotoxicity in the VERO mammalian cell line was also evaluated, and the selectivity index was calculated. Bio-AgNPs have an antibacterial activity with MIC and MBC ranging from 0.460 to 1.870 µg/ml. The combination of polymyxin B and Bio-AgNPs presents synergy against four of the five strains tested and additivity against one strain in the checkerboard assay. Considering the time of cell death, Bio-AgNPs killed all carbapenem-resistant isolates and ATCC ® 19606 ™ within 1 h. When combined, Bio-AgNPs presented 16-fold reduction of the polymyxin B MIC and showed a decrease in terms of viable A. baumannii cells in 4 h of treatment, with synergic and additive effects. Protein leakage was observed with increasing concentrations for Bio-AgNPs treatments. Additionally, Bio-AgNP and polymyxin B showed dose-dependent cytotoxicity against mammalian VERO cells and combined the cytotoxicity which was significantly reduced and presented a greater pharmacological safety. Conclusions:The results presented here indicate that Bio-AgNPs in combination with polymyxin B could represent a good alternative in the treatment of carbapenemresistant A. baumannii. Significance and Impact of Study:This study demonstrates the synergic effect between Bio-AgNPs and polymyxin B on carbapenem-resistant A. baumannii strains.

Activity of biogenic silver nanoparticles against isolates of Prototheca species from bovine mastitis

“…A novel candidate may be silver nanoparticles (AgNP) that have high therapeutic potential. Several studies have demonstrated their antimicrobial properties, including activity towards multiresistant bacteria (Tang and Zheng 2018;Allend et al 2022) and biofilms of Staphylococcus aureus (Tran and Tran 2021), and activity towards isolates of Prototheca spp. (Jagielski et al 2018).…”

Polymyxin B, Cefoperazone Sodium-Sulbactam Sodium, and Tigecycline against Multidrug-Resistant Acinetobacter baumannii Pneumonia

“…It is an opportunistic pathogen with a strong ability to replicate and clone, and its rapid transmission brings about its worldwide prevalence [ 1 , 2 ]. A. baumannii is clinically common and possesses strong environmental adaptability and long survival period [ 3 ]. Multidrug-resistant A. baumannii (MDRAB) is one of the main causes of hospital-acquired infections and critical patient deaths [ 4 ].…”

Bright Side of Fusarium oxysporum: Secondary Metabolites Bioactivities and Industrial Relevance in Biotechnology and Nanotechnology

“…This could be a great future alternative in bacterial infection control, where smaller doses of these AgNPs are required with the same antibacterial activity [120]. Besides, its combination with polymyxin B showed a 16-fold reduction of the MIC of polymyxin B and decreased carbapenem-resistant Acinetobacter baumannii viability with additive and synergic effects, as well as significantly reduced cytotoxicity towards mammalian Vero cells, indicating its pharmacological safety [121]. The AgNPs synthesized with F. oxysporum f.sp.…”