811. Biofilms and Extremity Wound Infections in Combat Casualties: A Case-Control Study
Session: Poster Abstract Session: Bone and Joint
Friday, October 4, 2013
Room: The Moscone Center: Poster Hall C
Posters
  • TIDOS BIOFILM IDSA 2013.pdf (445.8 kB)
  • Background:   Extremity wound infections (EWI) cause significant morbidity among combat-injured US military personnel. Surface-attached communities known as biofilms may hinder the eradication of infection, yet clinical studies are lacking which confirm biofilm formation is a risk factor for relapse. 

    Methods:  Bacterial isolates and clinical data from subjects with EWI were collected in the Trauma Infectious Disease Outcomes Study (TIDOS).  Bacterial biofilms from clinical isolates of Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and E. coli were grown in 96-well plates over 48h in LB or TSB at 37șC.  Biofilms were stained with Crystal Violet (CV) and measured as the 570nm absorbance of CV solubilized in ethanol.  Absorbance above that from S. epidermidis ATCC 12228 was considered positive for biofilm formation. Cases (isolates of the same organism ≥7 days apart with any isolate being biofilm-positive) were compared to controls (non-recurrent isolates), matched by organism.  Fisher's exact and Wilcoxon rank-sum tests (SAS v9.3) were used to compare categorical and continuous variables, respectively.

    Results:   239 bacterial isolates from 77 subjects with EWI (age 24.2 ± 5.1 years, 60 (78%) male, 17 (22%) unknown gender, 59 (77%) from confirmed combat trauma) were included for analysis.  53 (69%) had lower extremity injuries, 12 (16%) had upper extremity injuries and 2 (3%) had injuries to upper and lower extremities.  Cases and controls did not differ with respect to age (P=0.79) or site of infection (P=0.40). 

     

    Biofilm

    Control

    Case

    P

    Power

    A. baumannii

    Neg

    17 (94%)

    1 (6%)

    <0.01

    96.1%

    Pos

    7 (39%)

    11 (61%)

     

     

    E. coli

    Neg

    9 (75%)

    3 (25%)

    0.40

    6.6%

    Pos

    5 (56%)

    4 (44%)

     

     

    K. pneumoniae

    Neg

    0

    0

    1.00

    *

    Pos

    1 (50%)

    1 (50%)

     

     

    P. aeruginosa

    Neg

    2 (100%)

    0

    0.53

    *

    Pos

    22 (65%)

    12 (35%)

     

     

    S. aureus

    Neg

    0

    0

    1.00

    *

    Pos

    4 (57%)

    3 (43%)

     

     

    * Unable to calculate

    Conclusion:   Biofilm formation was associated with relapsing EWI for A. baumannii.  Statistical power was limited due to a scarcity of non-relapsing infections.  More data are needed to confirm biofilm formation as a risk factor for relapsing EWI.

     

    Kevin S. Akers, MD1,2, Katrin Mende, PhD2,3, Kristelle Cheatle, BA2, Wendy Zera, BS3, Xin Yu, MS2, Miriam Beckius, MPH2, Deepak Aggarwal, MSE, MSPH3, Ping Li, MPH3, Carlos J. Sanchez Jr., PhD1, Joseph Wenke, PhD1, Amy Weintrob, MD3, David Tribble, MD, DrPH3, Clinton K. Murray, MD2 and the IDCRP TIDOS Investigative Team, (1)US Army Institute of Surgical Research, Fort Sam Houston, TX, (2)Brooke Army Medical Center, Fort Sam Houston, TX, (3)Infectious Disease Clinical Research Program, Uniformed Services University of the Health Sciences, Bethesda, MD

    Disclosures:

    K. S. Akers, None

    K. Mende, None

    K. Cheatle, None

    W. Zera, None

    X. Yu, None

    M. Beckius, None

    D. Aggarwal, None

    P. Li, None

    C. J. Sanchez Jr., None

    J. Wenke, None

    A. Weintrob, None

    D. Tribble, None

    C. K. Murray, None

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