NOVEL MULTIDRUG RESISTANT PLASMIDS FROM KLEBSIELLA PNEUMONIAE
Background: Multidrug resistant (MDR) Klebsiella pneumoniae is widespread and causes various infections. 50% of all K. pneumoniae isolates are MDR due to carriage of extended-spectrum-b-lactamase-(ESBL)-encoding plasmids. We sequenced two ESBL-encoding plasmids, pKpnB199 and pKpnU95, harbored by K. pneumoniae strains causing hospital-associated bloodstream infection (KpnB199 isolate) and community-associated urinary tract infection (KpnU95 isolate).
Methods: Antibiotic susceptibility profiles were determined using Vitek-2 and interpreted according to the EUCAST breakpoints. ESBL genes were determined using multiplex PCR and sequencing. ESBL-carrying plasmids were purified, transformed to Escherichia coli DH10B and selected on LB agar plates containing ampicillin (100 μg/mL). ESBL-encoding plasmids from two representative blaCTX-M-positive transformants were purified and sequenced using the Illumina HiSeq platform and assembled using SPAdes v3.10.0. Bioinformatic analyses were performed for plasmid comparison and gene mapping.
Results: KpnB199 was resistant to all widely-used antibiotics except carbapenems, amikacin and colistin. KpnU95 was more sensitive compared to KpnB199, and was susceptible also to b-lactam/b-lactamase inhibitors, all aminoglycosides and ciprofloxacin. Plasmids pKpnB199 and pKpU95 sized 100-150Kb, were found to be distant but both were self-conjugable and belonged to IncF incompatibility group (plasmid sequence types IncF[F52:A-:B-] and IncF[F52:A-:B20]). pKpnB199 and pKpnU95 harbored 11 and 10 different antibiotic resistance genes (ARGs). pKpnB199 encoded for catA1, sul1, sul2, dfrA1, blaTEM-1B, blaOXA-1, aac(3)-IIa, aadA1, aadA5-dfrA17, and blaCTX-M-2. pKpU95 encoded for dfrA12-aadA2-sul1, strA-strB-sul2, aph(3`)-Ia, mph(A), blaCTX-M-15 and qnrS1.
Conclusions: We found two new MDR IncF plasmids in K. pneumoniae encoding multiple ARGs and different ESBL genes; pKpnU95 encoded also qnrS1 gene. The role of these MDR plasmids in K. pneumoniae physiology and pathogenesis should be elucidated.
Powered by Eventact EMS