LAUSR

Klebsiella pneumoniae is an important emerging pathogen of humans and animals which may lead to major clinical implications including mortality. Moreover the increased use of antibiotics has promoted emergence of carbapenem resistant strains and extended spectrum β-lactamase producers (ESBLs) of K. pneumoniae. Recently, phage therapy has gained momentum as a conceivable alternative against emerging antibiotic resistance. OBJECTIVE With the aim to explore the efficacy of phage therapy against virulent K. pneumoniae infection, the current study was undertaken to assess the therapeutic effects of a novel lytic phage-VTCCBPA43 in pneumonic mouse model. METHODS The tailed phage - VTCCBPA43 was assessed for it's growth kinetics, in vitro host range analysis, temperature and pH sensitivity. The protein constituents were analysed by SDS-PAGE and Lc MS/MS and the therapeutic efficacy was observed 2 hr post challenge with virulent K. pneumoniae in BALB/c mouse model. RESULTS The phage-VTCCBPA43 was found to exhibit high temperature (upto 80 °C) tolerant property. It was most active at pH 5, had a burst size of 172 PFU/ml and exhibited a narrow host range. It was identified as KP36 like phage by shotgun proteomics. Following intranasal application of a single dose of 2 × 109 PFU/mouse post challenge, presence of biologically active phage in vivo and a significant reduction of bacterial load in lungs at all time points was observed which was even more impressive at 96hpi, 6dpi and 10dpi. The loss of severity of lesions suggested overall beneficial effects of phage therapy using BPA43 in the pneumonic mouse model. CONCLUSION The current research represents first in vivo evidences for effective phage therapy against K. pneumoniae infection by using intranasal route.