Molecular epidemiology and resistance patterns of blaOXA-48Klebsiella pneumoniae and Escherichia coli: A nationwide multicenter study in Taiwan

Abstract

Background: We describe the molecular epidemiology and resistance patterns of bla_OXA-48Klebsiella pneumoniae and Escherichia coli in Taiwan.

Methods: In this multicenter surveillance study from January 2012 to August 2015, the identified bla_OXA-48Enterobacteriaceae isolates were subjected to antibiotics susceptibility testing. PCR method was used for detecting concomitant other beta-lactamases. Outer membrane porins were analyzed. Genetic relatedness and molecular epidemiology of the isolates were determined through pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Plasmid incompatibility was determined using PCR-based replicon typing.

Results: Forty-three bla_OXA-48K. pneumoniae and two E. coli isolates were analyzed. The annual incidence of bla_OXA-48K. pneumoniae isolates from 2012 to 2015 were 0%, 1.1%, 2.4%, and 7.6%, respectively. Forty-three (95.5%) of 45 isolates were non-susceptible to broad-spectrum beta-lactams (ceftriaxone, ceftazidime, cefepime, piperacillin/tazobactam), Forty-two (93.3%) of the 45 isolates showed resistance against all tested carbapenems (imipenem, meropenem, doripenem, and ertapenem). Molecular characterization revealed that they co-produced at least one extended-spectrum beta-lactamases or AmpC beta-lactamases, with at least one outer membrane porin loss. Thirty-eight (88.3%) of the 43 K. pneumoniae isolates belonged to ST11. PFGE analysis of 43 K. pneumoniae isolates revealed dissemination of multiple clones. Six of the 12 tested K. pneumoniae representatives of different pulso-types belonged to IncA/C.

Conclusion: Concomitant loss of porins and production of other beta-lactamases renders the bla_OXA-48-producing isolates in Taiwan a high-level carbapenem resistance and broad resistance against many beta-lactam antibiotics. Following dissemination of multiple clones of bla_OXA-48 K pneumoniae ST 11, a trend of increased bla_OXA-48 prevalence was noted.

Keywords: Escherichia coli; Klebsiella pneumoniae; OXA-48.