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Canadian Journal of Infectious Diseases and Medical Microbiology
Volume 20 (2009), Suppl A, Pages 20A-30A
http://dx.doi.org/10.1155/2009/518471
CANWARD 2007

Antimicrobial Susceptibility of 6685 Organisms Isolated from Canadian Hospitals: CANWARD 2007

George G Zhanel,1,2,3 Mel DeCorby,1,3 Kim A Nichol,1,3 Aleksandra Wierzbowski,1,3 Patricia J Baudry,1,3 Franil Tailor,1 Philippe Lagacé-Wiens,1,2,3 Andrew Walkty,1,2,3 Sergio Fanella,1,2,3 Oscar Larios,1,4 Michael R Mulvey,1,4 Melissa McCracken,1,4 James A Karlowsky,1,3 The Canadian Antimicrobial Resistance Alliance (CARA), and Daryl J Hoban1,3

1Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Canada
2Department of Medicine, Health Sciences Centre, MS673-Microbiology, Canada
3Department of Clinical Microbiology, Health Sciences Centre, MS673-Microbiology, Canada
4Nosocomial Infections Branch, National Microbiology Laboratory, Health Canada, Winnipeg, Manitoba, Canada

Copyright © 2009 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

BACKGROUND: Antimicrobial resistance is a growing problem in North American hospitals as well as hospitals worldwide. OBJECTIVES: To assess the antimicrobial susceptibility patterns of commonly used agents against the 20 most common organisms isolated from Canadian hospitals. METHODS: In total, 7881 isolates were obtained between January 1, 2007, and December 31, 2007, from 12 hospitals across Canada as part of the Canadian Ward Surveillance Study (CANWARD 2007). Of these, 6685 isolates (20 most common organisms) obtained from bacteremic, urinary, respiratory and wound specimens underwent antimicrobial susceptibility testing. Susceptibility testing was assessed using the Clinical and Laboratory Standards Institute broth microdilution method. RESULTS: The most active (based upon minimum inhibitory concentration [MIC] data only) agents against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) were dalbavancin, daptomycin, linezolid, telavancin, tigecycline and vancomycin, with MICs required to inhibit the growth of 90% of organisms (MIC90) of 0.06 μg/mL and 0.06 μg/mL, 0.25 μg/mL and 0.25 μg/mL, 4 μg/mL and 1 μg/mL, 0.25 μg/mL and 0.25 μg/mL, 0.5 μg/mL and 0.25 μg/mL, and 1 μg/mL and 2 μg/mL, respectively. The most active agents against vancomycin-resistant enterococci were daptomycin, linezolid and tigecycline with MIC90s of 2 μg/mL, 4 μg/mL and 0.12 μg/mL, respectively. The most active agents against Escherichia coli were amikacin, cefepime, ertapenem, meropenem, piperacillin-tazobactam and tigecycline with MIC90s of 4 μg/mL, 2 μg/mL, 0.06 μg/mL or less, 0.12 μg/mL or less, 4 μg/mL and 1 μg/mL, respectively. The most active agents against extendedspectrum beta-lactamase-producing E coli were ertapenem, meropenem and tigecycline with MIC90s of 0.12 μg/mL or less, 0.12 μg/mL or less and 1 μg/mL, respectively. The most active agents against Pseudomonas aeruginosa were amikacin, cefepime, meropenem and piperacillin-tazobactam with MIC90s of 32 μg/mL, 32 μg/mL, 8 μg/mL and 64 μg/mL, respectively. The most active agents against Stenotrophomonas maltophilia were tigecycline and trimethoprimsulfamethoxazole and levofloxacin with MIC90s of 8 μg/mL, 8 μg/mL and 8 μg/mL, respectively. The most active agents against Acinetobacter baumannii were amikacin, fluoroquinolones (eg, levofloxacin), meropenem, and tigecycline with MIC90s of 2 μg/mL or less, 1 μg/mL, 4 μg/mL and 2 μg/mL, respectively. CONCLUSIONS: The most active agents versus Gram-positive cocci from Canadian hospitals were vancomycin, linezolid, daptomycin, tigecycline, dalbavancin and telavancin. The most active agents versus Gram-negative bacilli from Canadian hospitals were amikacin, cefepime, ertapenem (not P aeruginosa), meropenem, piperacillintazobactam and tigecycline (not P aeruginosa). Colistin (polymyxin E) was very active against P aeruginosa and A baumannii.