Abstract
Genetic determinants of a clinical Klebsiella pneumoniae isolate (KP1814) coproducing IMP-4 and a rare ESBL gene SFO-1 was investigated. KP1814 belongs to a novel sequence type (ST) assigned to ST2270. WGS identified four circular DNA sequences in KP1814, including two multidrug-resistance (MDR) plasmids, one virulence plasmid, and one circular form. The MDR plasmid pKP1814-1 (299.9 Kb) is untypeable, and carries two large mosaic multiresistance regions (MRRs). blaSFO-1 and blaIMP-4 co-exists on MRR1, and blaSFO-1 is associated with an IS/Tn-independent genetic context. blaIMP-4 is carried by a novel In804-like integron (intlI-blaIMP-4-Kl.pn.I3-qacG2-aacA4-catB3∆) associated with a novel Tn1696-like transposon (designed Tn6404) flanked by IS5075. The other MDR plasmid pKP1814-3 is a 95,701-bp IncFII plasmid, and is a hybrid of a Shigella flexneri plasmid pSF07201 and an E. coli plasmid pCA08. All resistance genes of pKP1814-3 were detected in a ~16-kb IS26-flanked composite transposon carried by a Tn5396 transposon. The circular form (18.3 Kb) was composed of two parts belonging to pKP1814-1 and pKP1814-3, respectively. The plasmid pKP1814-2, carrying multiple virulence factors, encodes IncFIBK and IncFIIK replicons with a size of 187,349 bp. The coexistence of MDR and virulence plasmids largely enhances the bacterial fitness in the host and environment.
Highlights
China, plasmid-borne blaIMP-4 has been sporadically reported in different provinces/cities
ESBL phenotype was confirmed by the double-disc synergy test (DDST) using cefotaxime (30 μg) and ceftazidime (30 μg) with clavulanate (10 μg) discs
KP1814 was resistant to numerous drugs, including ertapenem, and remained susceptible to amikacin, ciprofloxacin, and levofloxacin (Table S1)
Summary
The community-associated K. pneumoniae strain KP1814 was collected in the frame of a national-wide survey for antibacterial resistance among outpatients with community-associated infections[19]. This strain was isolated from an outpatient (the type of clinical specimen was unknown) in a secondary hospital in mid-south of China (Hubei province) in 2011. De novo assembly for reads yielded by Hiseq2500 was done by CLC Genomics Workbench v8.0 (QIAGEN, Hilden, Germany) after quality trimming (Qs ≥ 20), and the scaffolding was performed by SSPACE standard version 3.0 with default settings[20]. The three plasmids and the circular form have been deposited at DDBJ/EMBL/GenBank under the accession of KX839207- KX839210
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