Draft genome sequence analysis of a novel MLST (ST5028) and multidrug-resistant Klebsiella quasipneumoniae subsp. similipneumoniae (Kp4) strain 456S1 isolated from a pig farm in China

Objectives: The avian breeding industry is an important element in exposing bacteria to antibiotics. As one of the major animal welfare and economic problems for the poultry industry, multidrug-resistant Klebsiella spp. have become a substantial source of antibiotic resistance genes. In the present work, we reported the draft genome sequence of a novel multilocus sequence type (MLST) (ST5028) Klebsiella quasipneumoniae subsp. similipneumoniae (Kp4) strain 456S1, which was isolated from a pig farm in China with broad-spectrum antimicrobial activities.

Methods: Classical microbiological methods were applied to isolate and identify the strain, genomic DNA was sequenced using an Illumina HiSeq platform, and the reads were de novo assembled into contigs using CLC Genomics Workbench. The assembled contigs were annotated, and whole-genome sequencing (WGS) analysis was performed.

Results: WGS analysis revealed that the genome of strain 456S1 comprised a circular chromosome of 5,419,059 bp (GC content, 57.8%), harbouring 12 important antibiotic resistance genes: aac(6')-ib-cr, aadA16, floR, dfrA27, fosA, tet(D), blaOKP-B-3, oqxA, oqxB, qnrB6, sul1 and arr-3. The Klebsiella quasipneumoniae subsp. similipneumoniae (Kp4) 456S1 was also found to belong to a novel sequence type (ST5028) determined by MLST.

Conclusion: The genome sequence reported herein will provide useful information for antibiotic resistance and pathogenic mechanisms in Klebsiella quasipneumoniae and will be a reference for comparative analysis with genomic features among different sources of clinically important multidrug-resistant strains, especially among bacteria of animal and human origin.