Inhibition of the Vancomycin Resistance in Staphylococcus aureus in Egypt Using Silver Nanoparticles.

Staphylococcus aureus is a major human pathogen that is sometimes resistant to vancomycin. In this study, the prevalence of vancomycin-resistant Staphylococcus aureus (VRSA) was studied. 100 isolates of S. aureus were identified based on biochemical and molecular evidence. The antibiotic susceptibility of the studied isolates was tested against 13 antibiotics by the disc diffusion method that showed 24 vancomycin-resistant isolates. The minimum inhibitory concentrations (MICs) were estimated by the agar dilution method to determine vancomycin intermediate-resistant S. aureus (VISA) and VRSA. The resistance gene cluster (vanA, vanR, vanH, and vanY) was amplified by PCR and then sequenced. Amplification of vanA and vanR genes showed that they are present in 21.4% and 14.3% of VRSA isolates, respectively, whereas none of the studied genes has been detected in VISA strains. A significant antimicrobial effect toward VRSA isolates using silver nanoparticles (AgNPs) synthesized from S. aureus and rosemary leaves was recorded. This study confirmed the existence of VRSA strains in Egypt. Furthermore, the use of silver nanoparticles inhibits these vancomycin-resistant S. aureus strains in vitro.

The beneficial effects of a multistrain potential probiotic, formic, and lactic acids with different vaccination regimens on broiler chickens challenged with multidrug-resistant Escherichia coli and Salmonella.

The effects of a multistrain potential probiotic (Protexin®), acids, and a bacterin from multidrug-resistant E. coli O26, O78, S. Enteritidis (1,9,12 g.m1,7), and S. Typhimurium (1,4,5,12.i.1,2) on the immune response, haematological parameters, cytokines, and growth parameters of broiler chickens challenged with bacterin live serotypes were investigated. Two experiments were designed using 300 one-day-old chicks (Arbor Acres) randomly assigned to 15 groups. The first experiment comprised 9 groups, including positive and negative control groups and other groups received Protexin®, acids, and the bacterin (0.2 ml/SC), either alone or in combination, on the 1st day. The second experiment contained 6 groups, including positive and negative control groups and other groups received a combination of Protexin®, acids, and the bacterin (0.5 ml/SC) on the 8th day. All the groups except the negative control groups were challenged on the 8th and 16th days in both experiments, respectively, with mixed live bacterin serotypes. The groups that received Protexin®, acids, and the bacterin either alone or in combination revealed significant improvements in the immune response to the bacterin (p ≤ 0.05). The groups in the 1st experiment and most the 2nd experiment groups showed a reduced mortality rate and decreased levels IFN-γ, IL-4, and IL-12 cytokines (p ≤ 0.05). Moreover, these groups demonstrated increases in haematological parameters and reduced rates of infection-caused anaemia. These groups showed significant increases in growth performance parameters, such as body weight, weight gain, and the feed conversion ratio (FCR) (p ≤ 0.05). There was a beneficial effect on 1-day-old chickens produced by combining Protexin®, acids, and the bacterin (0.2 ml/SC).

Antibacterial activity of fusion from biosynthesized acidocin/silver nanoparticles and its application for eggshell decontamination.

Bacteriocins from lactic acid bacteria (LAB) are useful to control the persistent development of pathogenic microorganisms in food and medicine fields. The bacteriocin acidocin was extracted from Lactobacillus acidophilus M1 that was isolated from fermented milk, purified using ammonium sulphate fractionation, and gel filtration column chromatography using Sephadex matrix and applied as a potential antibacterial agent. The molecular weight of the purified acidocin was estimated using SDS-PAGE to be 6.6 kDa. The acidocin was compared with silver nanoparticles (SNPs), biosynthesized by Aspergillus brasiliensis (niger) ATCC 16404, against two bacterial strains Bacillus cereus ATCC 14579 and Staphylococcus aureus ATCC 25923. Both acidocin and SNPs showed significance antibacterial effects using disc and well diffusion methods; the maximum antibacterial activity was proved against B. cereus from acidocin/SNPs composite using a ratio of 1/1 from each agent. The application of acidocin/SNPs composite as immersion solution, for disinfecting chicken eggshells, resulted in remarkable reduction in microbial load on the shells of 5.53 log10 CFU/eggshell. Results could provide an eco-friendly approach for potential antimicrobial composites to be used in food preservation and other health protection researches.