Identification of a phage-derived depolymerase specific for KL47 capsule of Klebsiella pneumoniae and its therapeutic potential in mice
Min Li;Hui Wang;Long Chen;Genglin Guo;Pei Li;Jiale Ma;Rong Chen;Hong Du;Yuqing Liu;Wei Zhang;College of Veterinary Medicine, Nanjing Agricultural University;Key Lab of Animal Bacteriology, Ministry of Agriculture;MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University;Department of Clinical Laboratory, Zhangjiagang Hospital Affiliated to Soochow University;Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences;Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University;Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences;
Klebsiella pneumoniae is one of the major pathogens causing global multidrug-resistant infections. Therefore,strategies for preventing and controlling the infections are urgently needed. Phage depolymerase, often found in the tail fiber protein or the tail spike protein, is reported to have antibiofilm activity. In this study, phage P560isolated from sewage showed specific for capsule locus type KL47 K. pneumoniae, and the enlarged haloes around plaques indicated that P560 encoded a depolymerase. The capsule depolymerase, ORF43, named P560dep,derived from phage P560 was expressed, purified, characterized and evaluated for enzymatic activity as well as specificity. We reported that the capsule depolymerase P560dep, can digest the capsule polysaccharides on the surface of KL47 type K. pneumoniae, and the depolymerization spectrum of P560dep matched to the host range of phage P560, KL47 K. pneumoniae. Crystal violet staining assay showed that P560dep was able to significantly inhibit biofilm formation. Further, a single dose(50 μg/mouse) of depolymerase intraperitoneal injection protected 90%–100% of mice from lethal challenge before or after infection by KL47 carbapenem-resistant K. pneumoniae. And pathological changes were alleviated in lung and liver of mice infected by KL47 type K. pneumoniae. It is demonstrated that depolymerase P560dep as an attractive antivirulence agent represents a promising tool for antimicrobial therapy.