293. Measuring Prevalence and Incidence of Antimicrobial Resistance in Endotracheal Isolates of 9 Intensive Care Units
Session: Poster Abstract Session: HAIs in Children
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • FortinE - Prevalence and Incidence of resistance in 9 ICUs.pdf (1.2 MB)
  • Background: Little is known about the frequency of antimicrobial resistance in Québec inpatients. Moreover, the scientific literature suggests various methods to define this resistance. Using different definitions, this study aimed to measure prevalence and incidence of resistance in 9 intensive care units (ICUs) from Montréal.

    Methods: All patients admitted to participating ICUs (3 neonatal, 2 pediatric, 4 adult) between 2006 and 2010 were studied retrospectively. Using antimicrobial susceptibility tests performed on microorganisms isolated from endotracheal cultures, prevalence of resistance and incidence rates of ICU-acquired resistance were measured. Duplicates were excluded from prevalence measures and defined as the same microorganism isolated in a given patient within 2-day window; for sensitivity analyses, a 3-day window was also used. ICU-acquired resistance was defined as the detection of a resistant microorganism in a patient with a previously susceptible organism or with no positive culture, at least 2 days after admission to ICU; alternative definitions were also considered (3-day lag, treating intermediate as resistant).

    Results: The most prevalent resistances were carbapenem-resistant Pseudomonas sp. (CRP, 21 %), methicillin-resistant S. aureus (MRSA, 16 %) and piperacillin-tazobactam-resistant Pseudomonas sp. (PTRP, 13 %). These prevalences were significantly higher in adult ICUs, compared to pediatric and neonatal ICUs. The highest incidences were found with piperacillin-tazobactam-resistant coliforms (PTRC, 9.0 / 10,000 patient-days – pd), MRSA (6.6 / 10,000 pd), quinolone-resistant Pseudomonas sp. (QRP, 5.7 / 10,000 pd) and CRP (5.7 / 10,000 pd). These incidence rates were always significantly lower in neonatal ICUs compared to adult and pediatric ICUs. Alternative time windows usually had little impact on estimated prevalence and incidence rates. However, adding transitions from susceptible to intermediate increased incident cases by 20% for aminoglycoside-resistant coliforms, 18 % for PTRC and 16 % for QRP.

    Conclusion: Prevalence and incidence of the most frequent resistances vary according to ICU type.  Estimates are robust to changes in definition time windows.

    Elise Fortin, PhD(c)1,2, Milagros Gonzales, MSc3, Robert W Platt, PhD2, Patricia Fontela, MD PhD4, David L Buckeridge, MD PhD2, Philippe Ovetchkine, MD MSc5 and Caroline Quach, MD MSc2,3,6, (1)Institut National De Santé Publique Du Québec, Quebec, QC, Canada, (2)Epidemiology, Biostatistics, and Occupational Health, Mc Gill University, Montreal, QC, Canada, (3)Division of Infectious Diseases; Department of Pediatrics, The Montreal Children's Hospital, Montreal, QC, Canada, (4)Pediatric Intensive Care, The Montreal Children's Hospital, Montreal, QC, Canada, (5)Department of Pediatrics, Division of Infectious Diseases, CHU Sainte-Justine – University of Montreal, Montreal, QC, Canada, (6)Institut National De Santé Publique Du Québec, Montreal, QC, Canada


    E. Fortin, None

    M. Gonzales, None

    R. W. Platt, None

    P. Fontela, None

    D. L. Buckeridge, None

    P. Ovetchkine, None

    C. Quach, None

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