1217. In Vitro Activity of Ceftolozane-Tazobactam Versus Antimicrobial Non-Susceptible Pseudomonas aeruginosa Clinical Isolates Obtained from Across Canada as Part of the CANWARD study, 2008-2016
Session: Poster Abstract Session: Expanded Spectrum - New Antimicrobial Susceptibility Testing
Friday, October 6, 2017
Room: Poster Hall CD
Posters
  • Walkty CeftolozaneTazobactam IDWeek 2017.pdf (347.8 kB)
  • Background:  Ceftolozane-tazobactam (C/T) is a novel beta-lactam beta-lactamase inhibitor combination with a broad spectrum of activity that includes Pseudomonas aeruginosa.  The purpose of this study was to evaluate the in vitro activity of C/T and relevant comparators versus a large collection of antimicrobial non-susceptible (NS) P. aeruginosa clinical isolates obtained from patients across Canada (CANWARD, 2008-2016).

    Methods:  From January 2008 to December 2016, inclusive, 12 to 15 sentinel hospitals across Canada submitted clinical isolates from patients attending ERs, medical and surgical wards, hospital clinics, and ICUs (CANWARD).  Each center was asked to annually submit clinical isolates (consecutive, one per patient/infection site) from blood, respiratory, urine, and wound infections.  Susceptibility testing was performed using broth microdilution as described by CLSI.  Multidrug-resistant (MDR) P. aeruginosa were defined as isolates that tested NS to at least one antimicrobial from ≥3 classes.  Extensively drug-resistant (XDR) P. aeruginosa were defined as isolates that tested NS to at least one antimicrobial from ≥5 classes.

    Results:  3229 P. aeruginosa isolates were obtained as a part of CANWARD.  The in vitro activity of C/T and relevant comparators is presented below.    

    C/T

    Ceftazidime

    Meropenem

    Piperacillin-Tazobactam

    MIC50/MIC90

    %S

    MIC50/MIC90

    %S

    MIC50/MIC90

    %S

    MIC50/MIC90

    %S

    All Isolates

    (n = 3229)

    0.5/1

    98.3

    4/32

    83.0

    0.5/8

    81.0

    4/64

    84.1

    Ceftazidime NS

    (n = 550)

    1/4

    90.5

    32/>32

    0.0

    4/32

    47.6

    64/256

    20.0

    Ciprofloxacin NS

    (n = 735)

    1/4

    94.8

    8/>32

    63.0

    2/16

    55.1

    16/128

    64.5

    Colistin NS

    (n = 155)

    0.5/2

    92.9

    4/32

    76.8

    0.5/16

    78.7

    4/128

    81.9

    Gentamicin

    NS

    (n = 535)

    1/4

    93.8

    4/>32

    67.3

    1/32

    59.6

    8/128

    69.3

    Meropenem NS

    (n = 615)

    1/4

    94.6

    8/>32

    53.2

    8/32

    0.0

    16/256

    54.5

    Piperacillin-tazobactam NS

    (n = 515)

    1/4

    92.0

    32/>32

    14.6

    4/32

    45.6

    64/256

    0.0

    MDR

    (n = 463)

    1/4

    90.5

    32/>32

    19.7

    8/32

    22.5

    64/256

    21.4

    XDR

    (n = 84)

    2/16

    78.6

    >32/>32

    0.0

    16/>32

    0.0

    128/512

    0.0

    %S = percent susceptible

    Conclusion:  C/T demonstrated excellent in vitro activity versus antimicrobial NS P. aeruginosa clinical isolates, including MDR, XDR, and meropenem NS subsets.  It may prove useful in the treatment of infections caused by these organisms. 

    Andrew Walkty, MD1,2, Heather J. Adam, PhD1,2, Melanie Baxter, MSc3, Philippe Lagace-Wiens, MD3,4, James Karlowsky, PhD1,2, Daryl Hoban, PhD1,2 and George Zhanel, PhD3, (1)Diagnostic Services Manitoba, Winnipeg, MB, Canada, (2)Medical Microbiology, University of Manitoba, Winnipeg, MB, Canada, (3)Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada, (4)Shared Health, Winnipeg, MB, Canada

    Disclosures:

    A. Walkty, None

    H. J. Adam, None

    M. Baxter, None

    P. Lagace-Wiens, None

    J. Karlowsky, None

    D. Hoban, Abbott: Research relationship , Research support
    Achaogen: Research relationship , Research support
    Astellas: Research relationship , Research support
    Merck Canada: Research relationship , Research support
    Merck USA: Research relationship , Research support
    Paratek Pharma: Research relationship , Research support
    Pharmascience: Research relationship , Research support
    Sunovion: Research relationship , Research support
    Tetraphase: Research relationship , Research support
    The Medicines Co.: Research relationship , Research support
    Zoetis: Research relationship , Research support

    G. Zhanel, Achaogen: Research relationship , Research support
    Astellas: Research relationship , Research support
    Merck Canada: Research relationship , Research support
    Merck USA: Research relationship , Research support
    Paratek Pharma: Research relationship , Research support
    Pharmascience: Research relationship , Research support
    Sunovion: Research relationship , Research support
    Tetraphase: Research relationship , Research support
    The Medicines Co.: Research relationship , Research support
    Zoetis: Research relationship , Research support

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 4th with the exception of research findings presented at the IDWeek press conferences.