746. KPC Conjugation into Virulent Klebsiella pneumoniae
Session: Poster Abstract Session: Antimicrobials: Resistance Mechanisms
Friday, October 4, 2013
Room: The Moscone Center: Poster Hall C
  • IDSA_poster746_Koper.pdf (476.4 kB)
  • Background: In the past decade, carbapenemase producing Enterobacteriacae has become a major threat and burden to healthcare systems world wide. Most exhibit resistance to multiple classes of antibiotics making treatment decisions difficult.  Klebsiella pneumoniae (KP) is of particular concern as it is well known to cause invasive disease in Asia. Fortunately, the concomitance of hyperinvasiveness and carbapenem resistance in KP has not been observed presently.  However, there has been separate reports of endemic KPC KP strains and hypervirulent invasive KP strains found in New Jersey.   This study assesses the possibility of an invasive virulent K2 KP strain and it's capability of acquiring KPC.

    Methods: The two most commonly found KPC strains (KPC 2 and 3) at the VA NJHCS were used as donors.  A virulent K2 serotype KP isolate from a liver abscess patient in New Jersey was chosen as the recipient. Conjugation of KPC 2 and 3 into the K2 serotype KP isolate was performed. Antimicrobial susceptibility testing for the three isolates were done initially and of the tranconjugants afterwards.  KPC production by polymerase chain reaction (PCR) and amplicon sequencing confirmed KPC types. PCR was also used to detect virulence associated genes.  Lastly, serum resistance and intraperitoneal murine lethality tests among parental strains and transconjugants were done. 

    Results: KPC 2 and 3 were successfully conjugated and retained by the invasive K2 KP recipient isolate.  Antimicrobial susceptibility testing showed KPC 2 and 3 donor strains were resistant to more than four classes of antibiotics while the K2 isolate was only initially resistant to ampicillin.  After conjugation of KPC 2 and 3, the K2 KP transconjugants had become resistant to all beta lactams.   Additionally, the KPC K2 KP transconjugants continue to retain it's high serum resistance and murine lethality.

    Conclusion:   The results of this study shows that the possibility of a KPC containing virulent strain of invasive KP may be in our future. Conjugation and retainment of KPC by virulent K2 KP and the ability of the tranconjugants to maintian it's high serum resistance and murine lethality after conjugation was demonstrated in this study.  The ramifications of having an invasive KPC containing virulent KP would be disastrous on the healthcare system.

    Catherine Koper, MD1, Robert Eng, MD2, Tom Chiang, MD2 and Kris Siu, PhD3, (1)Infectious Disease, New Jersey Medical School, Newark, NJ, (2)Veterans Affair New Jersey Health Care System, East Orange, NJ, (3)Infectious Diseases and Tropical Medicine, Tri-Service General Hospital, Taipei, Taiwan


    C. Koper, None

    R. Eng, None

    T. Chiang, None

    K. Siu, None

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