Program Schedule

135
Fosfomycin Susceptibilities Among Uropathogenic Extended Spectrum Beta-Lactamase-producing Enterobacteriacea

Session: Poster Abstract Session: Antibiotic Stewardship
Thursday, October 9, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
Posters
  • Abbo Fosfomycin ID Week 9.29.14 Final_Upload.pdf (117.5 kB)
  • Background: Antimicrobial resistance among uropathogens is a global problem with limited therapeutic alternatives. The Urinary Tract Infection Drug Resistance Index (UTI-DRI) in the South-Atlantic Region of the United States has steadily increased in the last decade by 60% (baseline 16.9 in 1999 to 27.1 in 2010). Fosfomycin is a broad-spectrum antimicrobial that has attracted interest for the treatment of lower UTIs caused by Gram-negative uropathogens resistant to commonly used antimicrobials. Data regarding antimicrobial susceptibilities for Enterobacteriaceaein the United States are extremely scarce.

    Methods: Retrospective review of urines cultures performed at Integrated Regional Laboratories (IRL) serving 14 acute care (ACF) and 5 long-term care facilities (LTCF) in South Florida between January 2013 and December 2013. Urine cultures were from hospitalized patients, emergency departments and residents in LTCF.  Only Enterobacteriaceae isolates that tested non-susceptible to extended spectrum beta-lactam agents were included in the analysis. Isolates were considered to be ESBL-producing if they were intermediate (I), susceptible dose-dependent (SDD), or resistant (R) to any 3rd or 4th generation cephalosporin per the 2013 Clinical Laboratory Standards Institute (CLSI) breakpoints. Fosfomycin Kirby-Bauer disk diffusion susceptibilities were determined with a 200 ug disk using 2014 CLSI breakpoints: >16 S, 13-15 I, <12 R.

    Results: ESBL-producing Enterobacteriaciae from 290 ACF and 87 LTCF urine cultures were analyzed. The number of E. coli isolates ranged from 3-35 in ACF and 2-40 in LTCF. 93% of isolates in ACF and 97% in LTCF were susceptible (Table). Klebsiella and Proteus strains were less susceptible than E. colistrains.

    Table: Number and percent of urinary isolates susceptible to fosfomycin

    Species                       ACF                             LTCF

    E. coli                          202/209 (97%)            75/76 (99%)               

    K. pneumoniae            60/70 (86%)                9/10 (90%)

    K. oxytoca                   4/4 (100%)                  No data

    P. mirabilis                 5/7 (71%)                    0/1 (0%)

    All                                271/290 (93%)            84/87 (97%)

    Conclusion: Fosfomycin has excellent in vitro activity against urinary ESBL-producing Enterobacteriacea strains, especially E. coli, in South Florida acute and long-term care facilities.

    Lilian Abbo, MD, Medicine, Division of Infectious Diseases, University of Miami Miller School of Medicine, Miami, FL, Aida Casiano-Colón, PhD, Integrated Regional Laboratories, Ft Lauderdale, FL, Marissa Tysiak, PharmD, University of Miami Hospital, Miami, FL and Thomas M. Hooton, MD, University of Miami, Miami, FL

    Disclosures:

    L. Abbo, None

    A. Casiano-Colón, None

    M. Tysiak, None

    T. M. Hooton, None

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