Screening of the Pathogenic Escherichia coli Phage and the Bactericidal Effect Test
In order to provide technical support for the application of phage prevention and control of Escherichia coli,screening of the pathogenic Escherichia coli phage and its bactericidal effect test were carried out.Specific methods are as follows:a strain of Escherichia coli EL4 was isolated from the milk of a cattle farm in Liaoning Province.It was subjected to staining mi-croscopy,bacterial 16S rRNA sequencing,and animal pathogenicity test.The isolated bacteria were used as host bacteria to screen the phage,whose bactericidal effect was evaluated.The results showed that the colony morphology and microscopic exami-nation results of the isolated EL4 strain on Escherichia coli Eosin-Methylene Blue and MacConkey selective identification medium were consistent with the typical characteristics of Escherichia coli.The 16S rRNA gene was amplified by PCR,sequenced and an-alyzed,and the phylogenetic tree was constructed.The results showed that the strain was closely related to the Escherichia coli ge-netic evolution of APEC from chicken in South Korea,NADC from bovine in the United States and STEC from human Shiga toxin-producing Escherichia coli,and the homology was 99.65%.The strain can cause clinical symptoms and pathological changes such as diarrhea,loss of appetite,lethargy,yellow liver,splenomegaly and bleeding until death in chicks.Using this strain as the host strain,a clear and bright phage,named vB_EcoP_L4,which can produce halo rings,was screened from cattle farm sewage.The phage vB_EcoP_L4 could rapidly kill the host bacteria after co-culturing with the host bacteria for 3 h,and showed a strong bactericidal effect within 8 h,which had the potential to prevent and treat pathogenic colibacillosis.
Escherichia coliphagepathogenicitybactericidal test
万方数据
维普
