This study was carried out to evaluate the prevalence of Salmonella serogroups and serotypes and their virulence gene carriage in pig fecal samples from farms and slaughterhouses in some southern provinces of Vietnam. The presence of Salmonella was assessed based on culture enrichment of the collected samples and biochemical and serological analyses; 27.7% (51) of 184 samples were posititve for Salmonella. Based on the availability of antisera, serogroups were determined for 61% (31) of 51 isolates. Twenty isolates belonging to Salmonella serotypes Typhimurium (10 isolates), Anatum (8 isolates), Senftenberg (7 isolates), Paratyphi B (3 isolates), Paratyphi A (1 isolate), Montevideo (1 isolate), and Saintpaul (1 isolate) were further characterized by a multiplex PCR protocol targeting Salmonella invasion A and virulence plasmid C genes ( invA and spvC, respectively). Individual PCR assays were developed to detect genes for Salmonella enterotoxin ( stn) , Salmonella outer protein B ( sopB), and Salmonella fimbriae ( pef). Various carriage patterns were identified among tested isolates. The invA and sopB genes were found in all isolates, and the stn gene was found in 95% of the isolates. The spvC gene was found in only 5% of the Salmonella Typhimurium isolates. None of the isolates were positive for the pef gene. Among all isolates, the predominant genotypic virulence profile (virulotype) was characterized by the concomitant presence of invA, sopB, and stn in carrier strains. In contrast, two virulotypes comprising either invA, sopB, spvC, and stn or invA and sopB were identified for the Salmonella Typhimurium isolates. Virulotypes made up of multiple virulence genes were predominant in most Salmonella strains tested in this study, indicating that pigs might act as a reservoir for these virulent strains.
The aim of this study was to investigate the extraction method for R. tomentosa and C. zeylanicum leaves and the evaluation of antibacterial and antioxidant activities of crude extracts. The results of the study showed that the active ingredients of crude extracts were clearly separated by Thin-layer chromatography and the presence of rhodomyrtone in R. tomentosa crude extract and cinnamaldehyde in C. zeylanicum crude extract. R. tomentosa crude extract was antibacterial activity against Staphylococcus aureus with 13.1 mm of inhibition zone, but is not effective against Salmonella Typhimurium. C. zeylanicum leaf extract did not show antibacterial activity on both S. aureus and S. Typhimurium. At a dilution of 1/2 of the R. tomentosa crude extract can completely inhibit S. aureus growth. This study also indicated the presence of antioxidant compounds such as flavonoids, tannins, phenols and terpenoids in C. zeylanicum and R. tomentosa crude extracts. The results showed that R. tomentosa and C. zeylanicum crude extracts should be used as a biotherapy alternative to antibiotic therapy. However, further study would be needed to investigate the antibacterial activity of crude extracts in vivo.
Two groups of hens (control and immunization group) were arranged in an experimental design with an immunization schedule of 3 injections of BSA antigen. IgY antibodies were extracted from egg yolks by two precipitation processes (chloroform and polyethylene glycol precipitates) and quantified using a standard curve of protein concentration. The purification of IgYwas confirmed by SDS-PAGE. Total protein extracted from egg yoks were less contaminated with yellow pigments (lutein and zeaxanthin) by using chloroform precipitate. The 2nd week post-immunization, IgY concentration increased respectively to 3903 ± 726 μg.ml-1 (chloroform extraction process) and 2937 ± 294 μg.ml-1 (PEG extraction process) (P < 0.01). After 3rdimmunization, IgY level obtaining from in immunization group extracted by chloroform process (6633 ± 1166 μg.ml-1) increased 2.7 times higher than that in control group (2482 ± 414 μg.ml-1). Whereas IgY concentrations obtained from PEG extraction process were not significantly different between the experimental group and control group. Chloroform and PEG precipitation methods had the same protein profile on the SDSPAGE. IgY antibody was identified by the presence of bands corresponding with IgY heavy chain (67-70 kDa) and IgY light chain (25 kDa) for both precipitation processes.
Salmonella and E.coli possess different surface protein structures that can induce protective immune responses. Identification of these proteins capacitates development of diverse applications in prevention and diagnosis that contribute to effectively control disease-causing enterobacteria pathogens such as Salmonella and E.coli. A simple procedure for obtaining protein complexes of Salmonella serotypes and E.coli is performed in this study. A sonication process with heat treatment of whole bacteria induced the release of protein complexes. Concentration of the protein extract was quantified using protein quantification Kits-Rapid, and protein complex profile was obtained by SDS-PAGE (Sodium dodecyl sulfate polyacrylamide gel electrophoresis) and silver staining. The concentrations of protein ranged from 29.45 to 45.35 µg/mL in the Salmonella protein extracts, and from 25.35 to 36.72 µg/mL in the E.coli protein extracts. Six major groups of proteins from E. coli (YfiO, NipB, OmpF, YfgL, Talc, YaeT) and four major groups of proteins from Salmonella (Flagellin, OmpA, Porin, SEF21) were preliminarily determined by a simple procedure of extraction based on the molecular weight.
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