1044. Influence of ciprofloxacin prophylaxis on the antimicrobial susceptibility profile of gram-negative bacilli recovered from the bloodstream of patients admitted to a hematology/bone marrow transplant service
Session: Poster Abstract Session: Clinical Infectious Diseases: Bacteremia and Endocarditis
Friday, October 28, 2016
Room: Poster Hall
Posters
  • D6Bacteremia_Poster_Sept 2016_Trial_Oct3_FINAL OCT 3.pdf (448.7 kB)
  • Background:  Fluoroquinolones are widely prescribed for febrile neutropenia prophylaxis.  However, antimicrobial-resistant bacteria can be selected out during their use.  The primary objective of this study was to determine the impact of ciprofloxacin (CIP) prophylaxis on the antimicrobial susceptibility profile of gram-negative bacilli isolated from the bloodstream of patients admitted to a hematology/bone marrow transplant (BMT) service. 

    Methods:  Patients admitted to a hematology/BMT service in Winnipeg (Manitoba, Canada) between 2010 and 2015 with gram-negative bacteremia were retrospectively identified from a review of the microbiology laboratory database.  Patients could be included more than once in the analysis if at least one week had passed between bacteremia episodes.  A chart review was performed for all patients.  Abstracted data included patient demographic information, the isolate antimicrobial susceptibility profile, and receipt (or not) of CIP prophylaxis. 

    Results:  In total, 70 episodes of gram-negative bacteremia occurred among 48 patients over the study period (susceptibility profile in the table below).  The most common pathogens were Escherichia coli (36%), Pseudomonas aeruginosa (14%), Klebsiella pneumoniae (13%), Stenotrophomonas maltophila (9%), and Acinetobacter spp. (7%).  Twenty isolates were recovered from patients receiving CIP prophylaxis. 

    % Susceptible (number susceptible/number tested)

    Antimicrobial

    All isolates

    Isolates from patients not on CIP prophylaxis

    Isolates from patients on CIP prophylaxis

    P value for CIP prophylaxis vs no prophylaxis (chi-square test)

    Ceftazidime

    80.9 (55/68)

    85.7 (42/49)

    68.4 (13/19)

    0.10

    CIP or levofloxacin

    55.1 (38/69)

    70.0 (35/50)

    15.8 (3/19)

    <0.01

    Gentamicin

    73.9 (51/69)

    84.0 (42/50)

    47.3 (9/19)

    <0.01

    Meropenem

    88.4 (61/69)

    92.0 (46/50)

    78.9 (15/19)

    0.13

    Piperacillin-tazobactam

    77.9 (53/68)

    81.6 (40/49)

    57.8 (11/19)

    0.03

    Conclusion:  Gram-negative bacilli recovered from the bloodstream of patients receiving CIP prophylaxis tended to be more resistant to all antimicrobials evaluated, relative to those isolates recovered from patients not on prophylaxis.  Meropenem was the most active antimicrobial, with 88.4% of isolates remaining susceptible in vitro.

    Maher Alharbi, MD1, Andrew Walkty, MD1, Lawrence Law, MD2, Anas Merdad, MD2 and Eric Bow, MD3, (1)Section of Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada, (2)Internal Medicine, University of Manitoba, Winnipeg, MB, Canada, (3)CancerCare Manitoba, University of Manitoba, Winnipeg, MB, Canada

    Disclosures:

    M. Alharbi, None

    A. Walkty, None

    L. Law, None

    A. Merdad, None

    E. Bow, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.