Prevalence of antibiotic resistance genes and genetic relationship of Escherichia coli serotype O45, O113, O121, and O157 isolated from cattle in the Mekong Delta, Vietnam

A total of 39 Escherichia coli strains serotype O45, O113, O121, and O157 isolated from cattle in the Mekong Delta were examined the antimicrobial susceptibility to 13 antibiotics by the disc-diffusion method. Those strains were also analyzed for the presence of antibiotic resistance genes by PCR assay, and their genetic relationship by ERIC-PCR assay. The results of antimicrobial susceptibility testing showed that those strains were sensitive to most of the examined antibiotics, but were relatively high resistance to ampicillin (64.10%), and colistin (53.85%). Those E. coli strains could be resistant against one to eight antibiotics with 22 resistance patterns obtained. Moreover, those E. coli strains harbored one to seven antibiotic resistance genes. Gene tetA (51.28%) and blaampC (48.72%) were detected frequently while gene tetB, blaCMY, and cat1 were not found in those E. coli strains. A total of 21 combined patterns of antibiotic resistance genes were recorded, and the most frequent combined pattern was blaampC+tetA (12.82%). ERIC-PCR analysis revealed that each E. coli serotype exhibited various genetic patterns with 40%-100% of similarity. The most elevated number of patterns were in E. coli O157 (nine patterns), followed by E. coli O121 (six patterns). The prevalence of antibiotic resistance genes and diverse genetic characteristics in those E. coli strains originated from cattle constitute potential risks to local health in the Mekong Delta

Preparation and Assessment of Some Characteristics of Nanoparticles Based on Sodium Alginate, Chitosan, and Camellia chrysantha Polyphenols

This paper presents the characteristics, morphology, and properties of alginate/chitosan/polyphenol nanoparticles, in which polyphenols were extracted from Camellia chrysantha leaves collected in Tam Dao district, Vinh Phuc province (Vietnam). The alginate/chitosan/polyphenol nanoparticles were prepared by ionic gelation method at different polyphenol content. The characteristics and morphology of these nanoparticles were investigated using infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV-Vis), and scanning electron microscopy (SEM). Release kinetic of polyphenols from the alginate/chitosan/polyphenol nanoparticles was conducted in simulated human body fluids. The release kinetics of polyphenols from the above nanoparticles were also evaluated and discussed. The experimental results showed that the release process of polyphenols from the nanoparticles was dependent on three factors: time, pH of solution, and amount of polyphenols

Novel Nanoparticle Biomaterial of Alginate/Chitosan Loading Simultaneously Lovastatin and Ginsenoside RB1: Characteristics, Morphology, and Drug Release Study

Recently, plenty of interesting studies on improvement of bioavailability for poorly soluble drugs were implemented with different approaches such as using of combined biopolymers as a delivery system that allowed to enhancing drug solubility and bioavailability. In this work, alginate and chitosan were blended together in the form of polymeric particles, loaded with both lovastatin and ginsenoside Rb1 to producing the four-component nanoparticles by ionic gelation method. CaCl2 and sodium tripolyphosphate were used as gelation agent and cross-linking agent, respectively. The characteristics of obtained nanoparticles were studied by means of infrared spectra (IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dynamic light scattering (DLS). In combination, ginsenoside Rb1 and lovastatin both interacted with each other to improve the drug release ability of the polymer particles. The change of initial content of drugs in the nanoparticles has a negligible effect on the functional groups in the structure of the nanoparticles but has a significant impact on drug release process of both lovastatin and ginsenoside Rb1 from the nanoparticles in selective simulated body fluids. In addition, the synergistic interaction of lovastatin and ginsenoside Rb1 could be also observed through the modification of relative crystal degree and drug release efficiency

Adsorption Ability for Toxic Chromium (VI) Ions in Aqueous Solution of Some Modified Oyster Shell Types

In this paper, the chromium, Cr (VI), ion adsorption ability of oyster shell samples collected from two sea regions in Vietnam (Phu Yen province and Quang Ninh province) was investigated and compared. The oyster shell samples were calcined at different temperatures and denatured by using ethylenediaminetetraacetic acid (EDTA). The Cr (VI) ion adsorption ability of the prismatic (PP) and nacreous (NP) shell layers of oysters was also evaluated. The characteristics of oyster shell samples before and after treatment were determined by using analysis methods including XRD, IR, BET, UV-Vis, and FESEM. The Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models and fit statistic equations were used to study the adsorption isotherms of Cr (VI) ion adsorption by oyster shells. The Cr (VI) ions adsorption kinetic has been set up using four reaction models consisting of first-order, pseudo-first-order, second-order, and pseudo-second-order reaction models. Effects of experimental factors on the Cr (VI) ion adsorption process using oyster shells were also investigated and discussed in this work