一株高效裂解耐药肺炎克雷伯菌噬菌体vB_Kpn_ZJ_A32的生物学及基因组特性分析OA

This study was aimed at revealing the biological characteristics and genomic features of the phage vB_Kpn_ZJ_A32 against drug-resistant Klebsiella pneumoniae,and exploring its application value.Klebsiella pneumoniae(ATCC700603)was used as the host strain.The morphology of the phage plaques was observed via transmission electron microscopy.Biological characteristics were assessed through measurement of the MOI,one-step growth curve,lysis spectrum,and physicochemical sensitivity.Additionally,the complete genome sequence was obtained,and bioinformatics analyses such as functional module annotation,co-linearity analysis,and phylogenetic tree construction were performed.The phage vB_Kpn_ZJ_A32 formed plaques with diameters of approximately 1-2 mm with transparent centers.The head had a regular polyhedral structure,and the tail was relatively long.The MOI was 0.001,the incuba-tion period was 45 minutes,the onset period was 55 minutes,the lysis yield was 5.3×106 PFU/cell,and broad-spectrum lysis activity was observed against 24 clinical isolates(including 83.33%drug-resistant strains).Moreover,survival was observed at temperatures of 10-50℃or pH levels of 4-11,and under ultraviolet irradiation for 9 minutes or low ethanol concentrations(0%-25%).The genome was a double-stranded circular DNA,with a total length of 165 941 bp and a GC content of 39.6%.A total of 276 open reading frames were predicted and classified into seven functional modules:replication,structure,lysis,assembly and packaging,regulation,host in-teraction and hypothetical protein.In summary,the phage vB_Kpn_ZJ_A32 effectively lysed drug-resistant K.pneumoniae strains,and showed efficient lysis ability and broad environmental adaptability,thereby demonstrating its potential as a candidate therapeutic agent for drug-resistant bacterial infections.