Resistant elements in plasmid of extensive drug resistant Klebsiella pneumonia

Objective To understand the genetics mechanism of extensive drug resistant Klebsiella pneumoniae by analyzing its resistant elements in plasmid pJM45-1. Methods Whole genome sequencing for an extensive drug resistant K. pneumoniae strain was performed by using high throughput Roche 454 platform, then the resistant elements in its plasmid pJM45-1 were analyzed, and the cluster analysis was performed by using the sequences of the plasmids recorded by National Center of Biotechnology Information (NCBI) with Fast Minimum Evolution method. Results The length of plasmid pJM45-1 was 317 156 bp. The encoding genes of transfer genes of conjuagal plasmids, resistant genes to antibiotics and heavy metal ions, virulence factors, transposons and insertion sequences were detected in plasmid pJM45-1. Moreover, plasmid pJM45-1 was 99% identical to 45 995 bases in 94 281 bases of resistant plasmid R100 (Genbank accession No.AP000342.1), while 87% identical to 8322 bases in 99 159 bases of F plasmid (Genbank accession No.AP001918.1). So plasmid pJM45-1 might be a chimeric plasmid. In addition, plasmid pJM45-1 and plasmids in other K. pneumoniae isolates were in the same cluster, while plasmid pJM45-1 and plasmids in other enterobacteria isolates were in the different cluster. Conclusion The resistant genes to antibiotics and heavy metal ions in plasmid pJM45-1 played a key role in the development of the extensive drug resistance of K. pneumoniae. Furthermore, plasmid pJM45-1 is a conjugative transfer plasmid, and resistance genes could be horizontally transferred among bacteria to cause the spread of drug-resistant strains.