779. In vitro activity of Ceftazidime-Avibactam (CAZ-AVI) against 511 Gram-Negative Clinical Isolates obtained from cancer patients
Session: Poster Abstract Session: Antimicrobial Agents: Novel Agents
Friday, October 9, 2015
Room: Poster Hall
Posters
  • CAZ-AVI.pdf (495.6 kB)
  • Background:

    Patients with cancer develop bacterial infections often, especially during periods of neutropenia.  Increasing problems with older agents (reduced susceptibility, overt resistance, and toxicity) has highlighted the need to develop newer agents. Ceftazidime-avibactam is a novel agent and is bactericidal against β-lactamase-producing Gram-negative bacilli that might be useful in this setting.

     

    Methods:

    Clinical bacterial isolates were collected from the patient with blood stream infection at University of Texas MD Anderson Cancer Center.  The minimum inhibitory concentration (MIC) of 511 gram negative isolates were determined for different antibiotics CAZ-AVI, meropenem (MEM), ceftazidime (CAZ),  piperacillin-tazobactam (TZP) and cefepime (FEP) using the broth microdilution  method in  accordance with CLSI guidelines. All samples were tested in duplicate. Isolates were stratified by species and resistance profile, including extended spectrum B-lactamase (ESBL +, ESBL -) and carbapenemase production. . MIC50 and MIC90analyses were conducted to examine antibiotic resistance. 

     

    Results:

    CAZ-AVI was active against (ESBL- , ESBL+ Phenotype Escherichia coli and K. pneumoniae including ESBL+ strains.  MIC50/MIC90 of 0.6/1 ug/ml;  Among  non MDR  P. aeruginosa strains  the  MIC50/MIC90  were  2/4 ug/ml ;  for MDR  P. aeruginosa strains  the MIC50/MIC90 were  4/>32 ug/ml ,However the MIC90  for MEM, CAZ, TZP and FEP were >32, 64,256 and 64 respectively. Ceftazidime-avibactam was highly active against carbapenem resistant Enterobacteriaciae (CRE) MIC50/MIC90, 1/4  ug/ml. Compared to CAZ, TZP, and FEP.

     

    Conclusion:

    CAZ-AVI demonstrated potent activity against a large collection of  gram-negative organisms identified in our cancer patients. CAZ-AVI was more active   than currently available B- lactams, including towards organisms that are resistant to most currently available agents, such as CRE and MDR  P. aeruginosa strains.

    Ray Hachem, MD, FIDSA1, Ruth Reitzel, MS1, Kenneth Rolston, MD, FIDSA2 and Issam Raad, MD, FACP, FIDSA, FSHEA1, (1)Infectious Diseases, Infection Control & Employee Health, University of Texas MD Anderson Cancer Center, Houston, TX, (2)Dept. of Infectious Diseases, Infection Control and Employee Health, The University of Texas M. D. Anderson Cancer Center, Houston, TX

    Disclosures:

    R. Hachem, None

    R. Reitzel, None

    K. Rolston, None

    I. Raad, UT MD Anderson Cancer Center: Shareholder , Licensing agreement or royalty
    Novel Anti-Infective Technologies LLC: Shareholder , Licensing agreement or royalty

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