Molecular analysis of a prolonged spread of Klebsiella pneumoniae co-producing DHA-1 and SHV-12 β-lactamases

Young Kyung Yoon, Hye Won Cheong, Hyunjoo Pai, Kyoung Ho Roh, Jeong Yeon Kim, Dae Won Park, Jang Wook Sohn, Seung Eun Lee, Byung Chul Chun, Hee Sun Sim, Min Ja Kim

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4 Citations (Scopus)

Abstract

The study investigated molecular mechanisms for prolonged nosocomial spread of multidrug-resistant Klebsiella pneumoniae co-producing plasmid-mediated AmpC β-lactamase DHA-1 and extended-spectrum β-lactamase SHV-12. Forty-eight clinical isolates of K. pneumonia, resistant to the extended-spectrum cepha-losporins, were collected in a 750-bed university hospital over a year. The isolates were characterized for PCR-based β-lactamase genotypes, isoelectric focusing and pulsed-field gel electrophoresis (PFGE) profiles. Resistance transfer was performed by plasmid conjugation and confirmed by a duplex-PCR and Southern hybridization. On β-lactamase typing, the strains producing only the DHA-1 enzyme (n=17) or co-producing DHA-1 and SHV-12 enzymes (n=15) were predominant. Judging from a one year-distribution of PFGE profiles, the co-producer was spread primarily with single clonal expansion of the PFGE-type A with subtypes (n=14), whereas the strains producing only DHA-1 enzyme were spread simultaneously with the PFGE-type A (n=ll) and other PFGE types (n=6). Transconjugants of the co-producers were confirmed to harbor either both blaDHA-1 and blaSHV-12 or only the blaDHA-1. In conclusion, this study indicated that the persistent nosocomial spread of multidrug-resistant K. pneumoniae strains was primarily associated with expansion of a clone harboring both the blaDHA-1 and blaSHV-12 or the blaDHA-1 only, and to a lesser extent with the horizontal transfer of the resistant plasmids. Our observations have clinical implication for the control and prevention of nosocomial dissemination of multidrug-resistant K. pneumoniae strains.

Original languageEnglish
Pages (from-to)363-368
Number of pages6
JournalJournal of Microbiology
Volume49
Issue number3
DOIs
Publication statusPublished - 2011 Jun

Keywords

  • DHA-1
  • Klebsiella pneumoniae
  • SHV-12
  • plasmid
  • spread

ASJC Scopus subject areas

  • Microbiology
  • Applied Microbiology and Biotechnology

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