Characterization and genome analysis of a novel Klebsiella pneumoniae phage

Abstract:

[Background] With the widespread use and even abuse of antibiotics, the problem of bacterial resistance has become increasingly prominent. The use of phage to treat drug-resistant pathogens has begun to attract attention. [Objective] Biological characteristics and bioinformatics analysis of a newly found phage vB_KpnP_IME279 of Klebsiella pneumoniae. [Methods] A multi-drug resistant Klebsiella pneumoniae was used as the host strain to isolate phage from hospital sewage. We used the double-layer plate method to conduct the titer, optimal multiplicity of infection (optimal MOI), one-step growth curve and lysis spectrum of the phage. Phage morphology was observed by transmission electron microscopy after purification. Its genome was sequenced using the Illumina MiSeq sequencing platform. Complete genome sequence was used for genome annotation, comparative genomics and evolutionary analyses. [Results] A novel phage vB_KpnP_IME279 was successfully isolated from infected host cells. The optimal MOI of IME279 is 0.1. One-step growth curve shows that IME279 has a burst size of 140 PFU/cell and a latent period of 20 min. The genome of IME279 is 42 518 bp and 59.3% (G+C)mol%. Electron microscopic observation showed that the phage was belongs to the family Podoviridae. The BLASTn alignment showed that the genome of the phage had limited similarity with the currently known phages. The evolutionary relationship between phage IME279 and other Podoviridae phage was analyzed by gene phylogenetic tree of phage major capsid protein, which suggests IME279 is a new member of the Podoviridae phage. [Conclusion] Isolation and identification of the new phage of Klebsiella pneumonia and the biological characteristics, genome-wide sequencing and bioinformatics analysis will help study the relationship between Klebsiella pneumoniae phage and host and the treatment of multi-drug resistant bacteria with phages.

Key words:Klebsiella pneumonia, Phage, Biological characteristics, Genomic analysis