357. Incomplete Adoption of Clinical Laboratory Standards Institute (CLSI) Breakpoints to Detect Carbapenem Resistant Organisms
Session: Poster Abstract Session: HAI: Multi Drug Resistant Gram Negatives
Thursday, October 27, 2016
Room: Poster Hall
  • CLSI Standards IDWEEK 2016 - for Printing.ppt.pdf (1.0 MB)
  • Background:

    Serious infections with carbapenem-resistant Enterobacteriaceae, Pseudomonas, and Acinetobacter represent a major threat to patient safety. Clinicians depend on accurate microbiologic testing to guide clinical decision making. During recent years, CLSI has adopted lower, more sensitive carbapenem breakpoints. We surveyed California hospital laboratories for practices of antimicrobial susceptibility testing and identifying carbapenem resistance.


    The California Antimicrobial Resistance Laboratory Network Assessment (CARLA) was a cross-sectional, voluntary survey of microbiology directors at hospitals in California. We set an a-priori response threshold of 60% to ensure representative data. Non-respondents were contacted by phone to improve response rates. Microbiology standards were based on current CLSI breakpoints. Hospital bed size and patient volume data were obtained from the National Healthcare Safety Network (NHSN) 2015 Annual Survey.


    Respondents included 264 (67%) hospitals, including lab directors (n=165) and clinical scientists (n=97). Susceptibility testing methods included VITEK2 (n=170), MicroScan (n=63) BD Phoenix (n=19) and Sensititre (n=2). Susceptibility testing for new drugs could be accessed by 168 (64%) hospitals: 161 can test ceftolazone-tazobactam and 177 can test ceftazidime-avibactam. Current CLSI carbapenem breakpoints were used when testing Enterobacteriaceae [200 (76%)], P. aeruginosa [204 (77%)], and Acinetobacter spp. [206 (78%)]. Hospitals using current CLSI breakpoints were not significantly different by hospital type or bed size compared with those that had not yet updated their tests.


    Reliable detection of carbapenem resistance and the ability to evaluate susceptibility to new drugs are critical to clinical decision making. Many California hospital laboratories have not implemented updated CLSI breakpoints; the lower sensitivity of prior breakpoints can result in misclassification of infections and adversely affect patient care. With rising rates of carbapenem resistance, clinicians should be aware of local practices. Public health can alert and provide feedback to stakeholders to support implementation of current standards.

    James a. Mckinnell, MD1, Janet Hindler, MCLS, MT(ASCP)2, Erin Epson, MD3, Sam Horwich-Scholefield, MPH, CIC3, Loren Miller, MD, MPH1, Job Mendez, RN, MD1, Jeremias Martinez, BS1, Jacob Sinkowitz, HSD1, Dawn Terashita, MD, MPH4, Patricia Marquez, MPH, CIC4, Sandeep Bhaurla, MPH4, Marcelo Moran, MA, MPH4, Lindsey Pandes, MPH4, Christina Hershey, BA5 and Romney Humphries, PhD2, (1)Infectious Disease Clinical Outcomes Research (ID-CORE), LA Biomed at Harbor-UCLA Medical Center, Torrance, CA, (2)Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, CA, (3)Healthcare-Associated Infections Program, California Department of Public Health, Richmond, CA, (4)Los Angeles County Department of Public Health, Los Angeles, CA, (5)UCLA, Los Angeles, CA


    J. A. Mckinnell, None

    J. Hindler, None

    E. Epson, None

    S. Horwich-Scholefield, None

    L. Miller, None

    J. Mendez, None

    J. Martinez, None

    J. Sinkowitz, None

    D. Terashita, None

    P. Marquez, None

    S. Bhaurla, None

    M. Moran, None

    L. Pandes, None

    C. Hershey, None

    R. Humphries, 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.