Program Schedule

Impact of Culture Yield and Detection of Multi-Drug Resistant Organisms from CT-guided Abscess Drainage despite Prior Antibiotics

Session: Poster Abstract Session: Diagnostic Microbiology: Bacterial Infections
Saturday, October 11, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
  • Yield of IR guided abscess cultures poster.jpg (205.2 kB)
  • Background:

    Culture information obtained from CT-guided abscess drainage is used to direct therapy decisions. However, these cultures are often performed after antibiotics have been initiated and the effect of this on culture yield is unclear. The WHO describes increasing antibiotic resistance as a major global threat and so we also sought to determine the prevalence of MDROs in our population of patients with abscesses. Our objectives were to evaluate the yield of cultures obtained from CT-guided abscess drainage despite prior antibiotics, the prevalence of multi-drug resistant organisms (MDROs) and their impact on antibiotic management.


    This retrospective study evaluated 300 patients who underwent CT-guided aspiration or drainage for suspected infection (11/2011-9/2013) at a single academic medical institution. Patient imaging and clinical characteristics were evaluated by an Abdominal Imaging fellow. Culture results and antibiotic therapy were evaluated independently by an Infectious Diseases fellow. Statistical analysis was performed using the Kruskal-Wallis, Fisher exact and χ 2 tests.


    17 patients were excluded due to lack of pre-procedure antibiotics or cultures being sent. 283 patients constituted the final cohort, with average age of 55 and M:F ratio of 53:47. Leukocytosis was present in 165/283(58%) and fever in 64/283(23%). Cultures were positive in 208/283(74%) with change in management in 184/283(65%). Patients with positive cultures had a shorter median time difference between antibiotic initiation and drainage than those with negative cultures (1.0 vs. 3.7 days, p<0.001). Change in management included change of antibiotics in 70/186 (38%), narrowing therapy in 97/184 (49%) and cessation of antibiotics in 17/184 (9%). ID consultation was significantly correlated with change in therapy (p<0.006). MDROs were cultured in 51/283 (18%). Detection of MDROs was significantly correlated with change in therapy (p<0.002).


    Despite prior antibiotics, CT-guided drainage has a high yield of positive cultures, which have an impact on antibiotic therapy decisions. MDROs were detected in 18% of cases and this finding increased the likelihood of changes to antibiotic therapy.

    Ruvandhi Nathavitharana, MD MPH1, Kathryn Mc Gillen, MD2, Alexander Brook, PhD2, Maryellen Sun, MD2, Bettina Siewert, MD2, Vassilios Raptopoulos2, Robert Sheiman, MD2 and Olga Brook, MD2, (1)Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA, (2)Radiology, Beth Israel Deaconess Medical Center, Boston, MA


    R. Nathavitharana, None

    K. Mc Gillen, None

    A. Brook, None

    M. Sun, None

    B. Siewert, None

    V. Raptopoulos, None

    R. Sheiman, None

    O. Brook, None

    Findings in the abstracts are embargoed until 12:01 a.m. EDT, Oct. 8th with the exception of research findings presented at the IDWeek press conferences.

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