| Title |
Molecular Analysis of a Prolonged Spread of Klebsiella pneumoniae Co-producing DHA-1 and SHV-12 β-Lactamases |
| Author |
Young Kyung Yoon1,2, Hye Won Cheong3, Hyunjoo Pai4, Kyoung Ho Roh5, Jeong Yeon Kim1, Dae Won Park1,2, Jang Wook Sohn1,2, Seung Eun Lee6, Byung Chul Chun7, Hee Sun Sim2, and Min Ja Kim1,2,6* |
| Address |
1Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul 136-705, Republic of Korea, 2Institute of Emerging Infectious Diseases, Korea University College of Medicine, Seoul 136-705, Republic of Korea, 3Division of Infectious Diseases, Chungbuk National University Hospital, Cheongju 361-711, Republic of Korea, 4Department of Internal Medicine, Hanyang University, Seoul 133-791, Republic of Korea, 5Department of Laboratory Medicine, Korea University College of Medicine, Seoul 136-705, Republic of Korea, 6Infection Control Unit, Korea University Medical Center, Seoul 136-705, Republic of Korea, 7Department of Preventive Medicine, Korea University College of Medicine, Seoul 136-705, Republic of Korea |
| Bibliography |
Journal of Microbiology, 49(3),363-368, 2011,
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| DOI |
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| Key Words |
Klebsiella pneumoniae, spread, plasmid, DHA-1, SHV-12 |
| 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 cephalosporins, 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=11) 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. |
