In silico design and immunoinformatics analysis of a chimeric vaccine construct based on Salmonella pathogenesis factors.

Currently, there are two vaccines based on killed and/or weakened Salmonella bacteria, but no recombinant vaccine is available for preventing or treating the disease. We used an in silico approach to design a multi-epitope vaccine against Salmonella using OmpA, OmpS, SopB, SseB, SthA and FilC antigens. We predicted helper T lymphocyte, cytotoxic T lymphocyte, and IFN-γ epitopes. The FilC sequence was used as a bovine TLR5 agonist, and the linkers KK, AAY, GPGPG and EAAAK were used to connect epitopes. The final sequence consisted of 747 amino acid residues, and the expressed soluble protein (∼79.6 kDa) was predicted to be both non-allergenic and antigenic. The tertiary structure of modeled protein was refined and validated, and the interactions of vaccine 3D structure were evaluated using molecular docking, and molecular dynamics simulation (RMSD, RMSF and Gyration). This structurally stable protein could interact with human TLR5. The C-ImmSim server predicted that this proposed vaccine likely induces an immune response by stimulating T and B cells, making it a potential candidate for further evaluation for the prevention and treatment of Salmonella infection.

Effect of curcumin nanoparticles and alcoholic extract of Falcaria vulgaris on the growth rate, biofilm, and gene expression in Pseudomonas aeruginosa isolated from burn wound infection.

PURPOSE: This study aimed to investigate the effect of Curcumin nanoparticles and alcoholic extract of Falcaria vulgaris on the growth rate, biofilm, and gene expression in Pseudomonas aeruginosa isolated from burn wound infection. METHODS: The alcoholic extract of Falcaria vulgaris was purchased from Pasargad Company. Curcumin nanoparticles were synthesized. Antibacterial activity of Curcumin nanoparticles and alcoholic extract of Falcaria vulgaris was investigated by microdilution method alone and in combination. Biofilm inhibitory was investigated by microtitrplate method. Effect of Curcumin nanoparticles and alcoholic extract of Falcaria vulgaris were evaluated on algD gene expression via Real-Time PCR. Cytotoxicity was evaluated by MTT assay on HDF cell line. Then, the data were analyzed using SPSS software. RESULTS: Synthesized Curcumin nanoparticles were approved by Fourier Transform Infrared (FTIR), and Scanning Electron Microscope. The alcoholic extract of Falcaria Vulgaris showed significant antibacterial activity against multidrug resistance (MDR) P. aeruginosa isolates at a concentration of 156.25 µg/mL. Moreover, MIC of the curcumin nanoparticle for isolates was 625 µg/mL. Based on fraction inhibition concentration, synergy, and the additive effect were shown against %7.7, and %93.3 of MDRs, respectively. The sub-MIC concentration of the binary compound reduced biofilms and algD gene expression in P. aeruginosa isolates. The Biological function of HDF cell lines was desirable after the effect of the binary compound. CONCLUSIONS: Regarding our results, this combination can be suggested as a promising agent in terms of biofilm inhibitory and antimicrobial properties.

Prevalence of Integrons and Antibiotic Resistance Pattern in Acinetobacter baumannii Isolated from Clinical Samples of Iranian Patients: A Systematic Review and Meta-analysis.

BACKGROUND: Acinetobacter baumannii is an important opportunistic nosocomial pathogen. Class 1 integrons in A. baumannii plays a significant role in antibiotic resistance. Therefore, this study aimed to investigate the prevalence of integrons and antibiotic resistance pattern in A. baumannii isolated from clinical samples of Iranian patients. METHODS: The Medical Subject Headings (MeSH) and the keywords with the help of Boolean operators ("AND" or "OR") were used alone or in combination to conduct the search. The searching process was conducted in the Web of Science, PubMed, Cochrane Library, Scopus, and Google Scholar databases and, also Iranian databases. The search was restricted to relevant English and Persian cross-sectional publications reporting the prevalence of Int1 in A. baumannii isolated from clinical samples from 1 January 2000 to 31 December 2018. The data were analyzed using Comprehensive Meta-Analysis software. Regarding the heterogeneity of studies, the random effects model was used. Cochrane Q and I2 tests was used to evaluate statistical heterogeneity between the studies. RESULTS: Fifteen studies were included in the analysis. The combined prevalence of class 1 integrons in A. baumannii was 55.2% (95% CI: 44.8-65.1). The pooled prevalence of MDR A. baumannii isolates was 68.1%. The highest resistance belonged to Aztreonam, followed by Ciprofloxacin, and Ceftazidime with a resistance rate of 97.6%, 92.8%, and 91.6%, respectively. Tobramycin was reported as an effective antibiotic. CONCLUSIONS: The present study reported an alarmingly high prevalence of class 1 Integrons, and MDR isolates of A. baumannii recovered from clinical samples that should be considered.