1595. In Vitro Activity of Ertapenem and Comparators against Aerobic Gram-negative Intra-Abdominal Infection (IAI) Pathogens in the USA—SMART 2012
Session: Poster Abstract Session: Multidrug-Resistant Gram Negative Rods
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
  • IDSA 1595.pdf (217.5 kB)
  • Background:   The IDSA and the SIS updated guidelines for IAI therapy in 2010.  The Study for Monitoring Antimicrobial Resistance Trends (SMART) is a longitudinal surveillance study that has tracked the in vitro activity of drugs commonly used to treat IAI since 2002.  This report summarizes in vitro activity of amikacin (AK), ampicillin-sulbactam (AS), cefepime (CPE), cefotaxime (CFT), cefoxitin (CFX), ceftazidime (CAZ), ceftriaxone (CAX), ciprofloxacin (CP), ertapenem (ETP), imipenem (IMP), levofloxacin (LVX), and piperacillin-tazobactam (PT), against aerobic gram-negative bacilli (GNB) isolated in 2012 from IAI in the US.

    Methods:   12 laboratories in the US each collected up to 100 consecutive isolates of GNB from IAI in 2012 for a total of 991 isolates.  Isolates were sent to a central laboratory for confirmation of identification; ESBL status and broth microdilution susceptibility were determined using CLSI broth microdilution.  IAI was defined as hospital-associated (HA) or community-associated (CA) if cultured ≥48 hours or <48 hours post admission, respectively. Statistical significance was determined using Fisher's exact test.

    Results:    The 2 most prevalent species, E. coli and K. pneumoniae, accounted for 55% of all isolates, and had ESBL rates in HA/CA of 8%/7% and 15%/7%, respectively.  97% of 794 Enterobacteriaceae  were ETP susceptible (S). Susceptibility (with 95% confidence limits) of all isolates combined, using breakpoints appropriate for each species (0% S assumed for species with no breakpoints for any given drug) is summarized by HA and CA, below; asterisks by drug names indicate a significant difference (p<0.05) between HA and CA values.



    ·         ESBL rates in IAI in the US are relatively unchanged from earlier SMART reports, and remain much lower than reported in most countries, leading to higher levels of susceptibility to cephalosporins and fluoroquinolones than typically seen internationally.

    ·         All study drugs except AK and IMP had significantly lower %S in HA than in CA.

    ·         AK (97.8%) and ETP (97.2%) were the most active vs. Enterobacteriaceae, while AK (86.2%) and CAZ (78.7%) were the most active vs. non-Enterobacteriaceae.

    ·         SMART data can be useful to help guide evolving IAI treatment guidelines to reflect resistance trends.

    Robert Badal, B.S.1, Sibylle Lob, MD, MPH1, Daryl Hoban, PhD1, Samuel Bouchillon, MD1, Meredith Hackel, PhD, MPH1, Douglas Biedenbach, BS1, Stephen Hawser, PhD2 and Ian Morrissey, PhD2, (1)International Health Management Associates, Inc., Schaumburg, IL, (2)IHMA Europe Sārl, Epalinges, Switzerland


    R. Badal, Merck & Co., Inc.: Research Contractor, salary from IHMA which received grant from Merck

    S. Lob, Merck & Co., Inc.: Research Contractor,

    D. Hoban, Merck & Co., Inc.: Research Contractor and Speaker's Bureau, Grant recipient and Salary from IHMA, which receives grant from Merck

    S. Bouchillon, Merck & Co., Inc.: Research Contractor,

    M. Hackel, Merck & Co., Inc.: Research Contractor,

    D. Biedenbach, Merck & Co., Inc.: Research Contractor,

    S. Hawser, Merck & Co., Inc.: Research Contractor,

    I. Morrissey, Merck & Co., Inc.: Research Contractor,

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.