AUTHOR=Zhou Weilong , Liu Lu , Feng Yu , Zong Zhiyong 

TITLE=A P7 Phage-Like Plasmid Carrying mcr-1 in an ST15 Klebsiella pneumoniae Clinical Isolate

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.00011

DOI=10.3389/fmicb.2018.00011

ISSN=1664-302X

ABSTRACT=<p>A <italic>Klebsiella pneumoniae</italic> clinical strain, named SCKP83, was isolated and found to be resistant to colistin thanks to the presence plasmid-borne colistin resistant gene <italic>mcr-1</italic>. The strain was subjected to whole genome sequencing and conjugation experiments. The subsequent analysis indicated that the strain belongs to ST15 and the capsular type K41. In SCKP83, <italic>mcr-1</italic> was carried by a 97.4-kb non-self-transmissible plasmid, a 90.9-kb region of which was predicted as an intact phage. This phage was 47.79% GC content, encoded 105 proteins and contained three tRNAs. <italic>mcr-1</italic> was located downstream of two copies of the insertion sequence IS<italic>Apl1</italic> (one complete and one truncated) and was inserted in the <italic>ant1</italic> gene, which encodes a putative antirepressor for antagonizing C1 repression, in this phage. The phage is highly similar to phage P7 (77% coverage and 98% identity) from <italic>Escherichia coli</italic>. Several similar <italic>mcr-1</italic>-carrying plasmids have been found in <italic>E. coli</italic> at various locations in China, suggesting that these phage-like plasmids have circulated in China. The findings in this study suggest that the P7 phage-like plasmids are not restricted to <italic>E. coli</italic> and may represent new vehicles to mediate the inter-species spread of <italic>mcr-1</italic>.</p>