Effect of biosynthesized selenium nanoparticles using Nepeta extract against multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii

Antibacterial Potential of Biosynthesized Silver Nanoparticles Using Berberine Extract Against Multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa

The emergence of multidrug resistance in bacterial infections has limited the use of antibiotics. Helping the action of antibiotics is one of the needs of the day. Today, the biosynthesis of nanoparticles (NPs) is considered due to its safety and cost-effectiveness. In this study, we investigated the effect of biosynthesized silver nanoparticles (AgNPs) by Berberine plant extract against standard strains of multidrug-resistant (MDR) Acinetobacter baumannii and Pseudomonas aeruginosa. Utilized UV-Vis, FTIR, FESEM/EDX, XRD, DLS, and Zeta potential techniques to confirm the biosynthesis of NPs. Then, disk diffusion agar (DDA) and minimum inhibitory concentration (MIC) tests were performed using common classes of standard antibiotics and AgNPs on the mentioned bacteria. The synergistic action between AgNPs and antibiotics was evaluated by the checkerboard method. First, we obtained the confirmation results of the biosynthesis of AgNPs. According to the DDA test, both standard bacterial strains were sensitive to NPs and had an inhibition zone. Also, the MIC values showed that AgNPs inhibit the growth of bacteria at lower concentrations than antibiotics. On the other hand, the results obtained from checkerboard monitoring showed that AgNPs, in combination with conventional antibiotics, have a synergistic effect. The advantage of this study was comparing the antibacterial effect of AgNPs alone and mixed with antibiotics. The antibacterial sensitivity tests indicated that the desired bacterial strains could not grow even in low concentrations of AgNPs. This property can be applied in future programs to solve the drug resistance of microorganisms in bacterial diseases.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01136-y.

Effect of lipopeptide extracted from Bacillus licheniformis on the expression of bap and luxI genes in multi-drug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa

Recently, opportunistic pathogens like Acinetobacter baumannii and Pseudomonas aeruginosa have caused concern due to their ability to cause antibiotic resistance in weakened immune systems. As a result, researchers are always seeking efficient antimicrobial agents to tackle this issue. The hypothesis of the recent study was that probiotic products derived from bacteria would be effective in reducing drug resistance in other bacteria. This research aimed to investigate the antimicrobial properties of probiotic products from various bacterial strains, including Lactobacillus rhamnosus, Pediococcus acidilactisi, Bacillus coagulans, Bacillus subtilis, and Bacillus licheniformis. These were tested against multi-drug-resistant (MDR) standard strains A. baumannii and P. aeruginosa. B. licheniformis was found to be the most effective probiotic strain, possessing the LanA and LanM lantibiotic genes. The lipopeptide nature of the probiotic product was confirmed through high-performance liquid chromatography (HPLC) and Fourier-transform infrared spectroscopy (FTIR) techniques. The anti-biofilm and antimicrobial properties of this probiotic were measured using an SEM electron microscope and minimum inhibitory concentration (MIC) test. Real-time PCR (qPCR) was used to compare the expression of bap and luxI genes, which are considered virulence factors of drug-resistant bacteria, before and after treatment with antimicrobial agents. The MIC results showed that the probiotic product prevented the growth of bacteria at lower concentrations compared to antibiotics. In addition, the ΔΔCqs indicated that gene expression was significantly down-regulated following treatment with the obtained probiotic product. It was found that B. licheniformis probiotic products could reduce drug resistance in other bacteria, making it a potential solution to antibiotic resistance.

A Review of the Antibacterial, Fungicidal and Antiviral Properties of Selenium Nanoparticles

The resistance of microorganisms to antimicrobial drugs is an important problem worldwide. To solve this problem, active searches for antimicrobial components, approaches and therapies are being carried out. Selenium nanoparticles have high potential for antimicrobial activity. The relevance of their application is indisputable, which can be noted due to the significant increase in publications on the topic over the past decade. This review of research publications aims to provide the reader with up-to-date information on the antimicrobial properties of selenium nanoparticles, including susceptible microorganisms, the mechanisms of action of nanoparticles on bacteria and the effect of nanoparticle properties on their antimicrobial activity. This review describes the most complete information on the antiviral, antibacterial and antifungal effects of selenium nanoparticles.

Carbapenem-Resistant Acinetobacter baumannii: Biofilm-Associated Genes, Biofilm-Eradication Potential of Disinfectants, and Biofilm-Inhibitory Effects of Selenium Nanoparticles

This study aimed to investigate the biofilm-production ability of carbapenem-resistant Acinetobacter baumannii (CRAB), the biofilm-eradication potential of 70% ethanol and 0.5% sodium hypochlorite, the effects of selenium nanoparticles (SeNPs) against planktonic and biofilm-embedded CRAB, and the relationship between biofilm production and bacterial genotypes. A total of 111 CRAB isolates were tested for antimicrobial susceptibility, biofilm formation, presence of the genes encoding carbapenemases, and biofilm-associated virulence factors. The antibiofilm effects of disinfectants and SeNPs against CRAB isolates were also tested. The vast majority of the tested isolates were biofilm producers (91.9%). The bap, ompA, and csuE genes were found in 57%, 70%, and 76% of the CRAB isolates, with the csuE being significantly more common among biofilm producers (78.6%) compared to non-biofilm-producing CRAB (25%). The tested disinfectants showed a better antibiofilm effect on moderate and strong biofilm producers than on weak producers (p < 0.01). The SeNPs showed an inhibitory effect against all tested planktonic (MIC range: 0.00015 to >1.25 mg/mL) and biofilm-embedded CRAB, with a minimum biofilm inhibitory concentration of less than 0.15 mg/mL for 90% of biofilm producers. In conclusion, SeNPs might be used as promising therapeutic and medical device coating agents, thus serving as an alternative approach for the prevention of biofilm-related infections.