Antimicrobial Susceptibility of 6685 Organisms Isolated from Canadian Hospitals: CANWARD 2007
Authors: Zhanel George G , DeCorby Mel , Nichol Kim A , Wierzbowski Aleksandra , Baudry Patricia J , Tailor Franil , Lagacé-Wiens Philippe , Walkty Andrew , Fanella Sergio , Larios Oscar , Mulvey Michael R , McCracken Melissa , Karlowsky James A , The Canadian Antimicrobial Resistance Alliance (CARA)  , Hoban Daryl J 
Published: May 2016

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 MIC
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 MIC 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 MIC 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 MIC 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 MIC 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 MIC 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.