弯曲菌宽谱烈性噬菌体生物学特性、全基因组测序分析及初步应用OA

In order to explore a new pathway to control Campylobacter(C.)contamination,C.phage was isolated and purified from chicken fecal samples taking C.NCTC12662 as the host bacteria,followed by electron microscopy observation and biological characterization and genomic analysis.Meanwhile,its effect produced jointly with antibiotic was tested using a checkerboard method.The results showed that a strain of C.phage P-61 was isolated.It was shown that,by a transmission electron microscope,the phage particle had an icosahedral head with a diameter of 102.6 nm and a long tail with a length of 112.9 nm,falling into Caudovirales of Siphoviridae;the cleavage spectrum was 48.48%,with a titer of 5.5×1011 pfu/mL and multiplicity of infection(MOI)of 0.01;it was shown that,by one-step growth curve,the latent period was 20 min,the lysis period was about 130 min,and the lysis amount was 240 pfu/cell;the optimum temperature was 42℃with strong pH tolerance,and the titer was stable within the range of pH 5 to 9.The total length of phage genome was 130 425 bp,and the G+C content was 26.13%,there were 176 open reading frames and 3 tRNAs,but no virulence gene and antibiotic resistance gene were contained in the genome as predicted by software.It was measured by the checkerboard method that the lowest concentration of Ciprofloxacin was reduced to 1/8 MIC when P-61 was 106 pfu/mL,indicating an obviously combined bactericidal effect.In conclusion,the obtained phage P-61 had the biological characteristics of high titer,broad spectrum and strong adaptability to environment,and the genome information was clear,which could play a synergistic role in the combined application of antibiotics,indicating a possibility of clinical application such as disinfection and purification.Biological resources were provided by the study for future development and utilization of phage preparations.