Prophages contribute to genome plasticity of Klebsiella pneumoniae and may involve the chromosomal integration of ARGs in CG258.

Klebsiella pneumoniae is an important multidrug-resistant pathogen carrying prophages. Here we explore the contribution of prophages to bacterial evolution and fitness in silico. This study showed prophages contribute to remarkable genome plasticity of K. pneumoniae. The strains of CG258 possess several conserved prophages including the couple of P2-P4 prophages. CRISPR-Cas system has limited impact on the presence of prophages. The strong MLST-depended distribution of CRISPR-Cas and prophages and the high proportion of strains with self-targeting spacers may be the causes. Four core ARGs (blaSHV, fosA and oqxAB) were detected on almost all the chromosomes, but the acquired ARGs were only found in CG258 and CRISPR-positive strains. The factors influencing the chromosomal integration of ARGs in CG258 and CRISPR-positive strains may be different. In CG258, prophages may involve the chromosomal integration of ARGs. For CRISPR-positive strains, the immunity of CRISPR-Cas systems against invading ARG-bearing mobile genetic elements may accelerate the process.