C1-114. CMY-2 AmpC β-Lactamase-Bearing Plasmids Identified Among Escherichia coli from Canadian Water Sources and Clinical Isolates are Genetically Similar
Session: Poster Session: E. coli and Klebsiella sp. Enzymatic Resistance
Saturday, October 25, 2008: 12:00 AM
Room: Hall C
Background: Plasmid-mediated AmpC β-lactamases have been increasing in prevalence and diversity worldwide. The purpose of this study was to investigate the AmpC-bearing plasmids isolated from E. coli in Canadian water sources (WS) and compare them to clinical isolates (CI) from intensive care units (ICUs). Methods: 94 and 26 E. coli isolates producing CMY-2 AmpC β-lactamases were investigated from Canadian recreational beach/private well water sources and ICUs, respectively. Plasmids harboring CMY-2 were extracted and transformed by electroporation into E. coli DH10B. CMY-2 plasmids were selected for on LB plates containing ampicillin and cefoxitin. Plasmids were characterized by RFLP patterns digested with BglII and a multiplex PCR for replicon typing. Results: Replicon typing revealed that the CMY-2 plasmids were distributed among 4 predominant replicon types: repI1 (53.2%, 42.3%), repK/B (14.9%, 34.6%), repA/C (17%, 26.9%) and an unidentified (UI) replicon type (12.8%, 3.8%) from both WS and CI, respectively. Multiple replicon types were identified among 6.4% of water and 7.7% of clinical CMY-2 plasmids. RFLP patterns of plasmid transformant DNA from both WS and CI consisted of 4 clusters corresponding to the 4 prevalent replicon types. Genetically indistinguishable repK/B, repI1, and UI CMY-2 plasmids were identified among both water and CI. Conclusions: CMY-2 plasmids isolated from Canadian water and clinical E. coli isolates were divided into 4 clusters based on RFLP patterns corresponding to the prevalent replicon types: repI1, repK/B repA/C and UI. The presence of genetically indistinguishable CMY-2 plasmids in both Canadian water and clinical isolates demonstrates a possible link of the dissemination of these plasmids from contaminated water sources to humans.
Daryl J. Hoban, PhD1, George G. Zhanel, PhD2, Laura Mataseje3, Michael Mulvey, PhD4, N Neumann5, Patricia Baudry, BSc3 and  P. J. Baudry, None., (1)Health Sciences Centre, Winnipeg, MB, Canada, (2)Medical Microbiology, University of Manitoba, Winnipeg, MB, Canada, (3)University of Manitoba, (4)University of Manitoba, Winnipeg, MB, Canada, (5)Alberta Provincial Public Health Laboratory