Application of BI-EHEC and BI-EPEC bacteriophages to control enterohemorrhagic and enteropathogenic escherichia coli on various food surfaces

OBJECTIVES

The purposes of this study were to determine the Efficiency of Plating (EOP) value of Bacteriophage BI-EHEC and BI-EPEC and to evaluate the application of these bacteriophages in reducing population of EHEC and EPEC on various food samples.

RESULTS

In this study, we used bacteriophage BI-EHEC and BI-EPEC, which were isolated from previous study. Both phages were tested with other multiple pathotypes of intestinal pathogenic E. coli to determine the efficiency of plating. BI-EHEC had high efficiency toward ETEC with an EOP value of 2.95 but low efficiency toward EHEC with an EOP value of 0.10, while BI-EPEC had high efficiency toward EHEC and ETEC with EOP values of 1.10 and 1.21, respectively. As biocontrol agents, both bacteriophages able to reduce CFU of EHEC and EPEC in several food samples using 1 and 6-days incubation times at 4 [Formula: see text]. BI-EHEC reduced the number of EHEC with an overall percentage of bacterial reduction value above 0.13 log₁₀, while BI-EPEC reduced number of EPEC with reduction value above 0.33 log₁₀.

A New Approach for Controlling Agrobacterium tumefaciens Post Transformation Using Lytic Bacteriophage

Overgrowth of Agrobacterium tumefaciens has frequently been found in Agrobacterium-mediated plant transformation. This overgrowth can reduce transformation efficiency and even lead to explant death. Therefore, this research investigates an alternative way to mitigate or eliminate Agrobacterium after transformation using a bacteriophage. To develop this alternative method, we conducted effectiveness studies of two lytic bacteriophages (ΦK2 and ΦK4) and performed an application test to control Agrobacterium growth after transformation. According to plaque morphological characterization and molecular analysis, the two bacteriophages used in this experiment were distinct. Moreover, some stability physicochemical and growth kinetics, such as adsorption time and susceptibility test, also showed that both bacteriophages differed. On the other hand, the optimum temperature and pH of both phages were the same at 28-30 °C and pH 7. Further investigation showed that both ΦK2 and ΦK4 were able to reduce the overgrowth of A. tumefaciens post transformation. Moreover, applying the cocktail (mixture of ΦK2 and ΦK4) with antibiotic application eradicated A. tumefaciens (0% overgrowth percentage). This result indicates that the application of bacteriophage could be used as an alternative way to eradicate the overgrowth of A. tumefaciens subsequent to transformation.

Morphogenesis and Genetic Diversity of Some Virulent Phages Specific for Bacillus velezensis

<b>Background and Objective:</b> Phosphorus (P) is one of the most limiting nutrients for plant growth. Phosphorus deficiency is limiting crop production in many agricultural soils worldwide. The application of phosphorus solubilizing bacteria (PSB) to soils can replace or partially reduce using of inorganic P fertilizers. A bacteriophage, or phage, is a virus that infects a bacterial cell, taking over the host cell's genetic material. The four phages were propagated, purified, studied for the morphological properties, finally studying the genetic diversity. <b>Materials and Methods:</b> Obtained, examined the efficiency and identification of bacteria for solubilizing phosphorus. Isolation, studying the properties and studying genetic diversity. <b>Results:</b> Four virulent phages (Bv<sub>1</sub>, Bv<sub>2</sub>, Bv<sub>3</sub> and Bv<sub>4</sub>) specific for <i>Bacillus velezensis</i> were isolated from the Egyptian soil. The <i>Bacillus</i> phages were purified by alternative low and high-speed centrifugation methods. Electron micrographs showed that phages appeared to be a member of the <i>Siphoviridae </i>family based on their structure and particle morphology (the particles have a head and long non-contractile tail). Sodium Dodecyl Sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) technique was performed to determine the properties of viral proteins. It was found that the Bv<sub>1</sub> virus had five structural proteins, while Bv<sub>2</sub> and Bv<sub>3</sub> virus had eight structural proteins and finally, the Bv<sub>4</sub> virus had ten structural proteins. The purity and quantity of isolated DNAs were determined spectrophotometrically. Data showed that the concentration of Bv<sub>1</sub> DNA was 0.75 μg, Bv<sub>2</sub> DNA and Bv<sub>3</sub> DNA was 0.60 μg and finally Bv<sub>4</sub> DNA 0.55 μg μL<sup></sup><sup>1</sup>. The analysis of genetic material of <i>B. velezensis</i> phages was determined based on both the ISSR-PCR technique and the effect of restriction enzymes. Data showed different amplification patterns with all phages. <b>Conclusion:</b> The bacteriophages of <i>B. velezensis</i> were isolated from soil, propagated, purified, study some of its properties.