699. Relationship between Klebsiella pneumoniae Antimicrobial Resistance and Biofilm Formation
Session: Poster Abstract Session: Resistance Mechanisms: Gram-Negative
Thursday, October 4, 2018
Room: S Poster Hall
  • Cusumano Kleb Biofilm IDWeek 2018.pdf (1.2 MB)
  • Background: Klebsiella pneumoniae is a frequently multidrug-resistant organism with a high propensity to form biofilm. K. pneumoniae is the most common carbapenem-resistant Enterobacteriaceae (CRE), and labeled an urgent threat by the CDC. The relationship between K. pneumoniae biofilm formation and specific antimicrobial resistance patterns has not been well defined.

    Methods: K. pneumoniae isolates (n=139) were evaluated for antimicrobial resistance and biofilm formation (CDC, Providence VA Med. Ctr., Rhode Island Hosp., BEI, and ATCC). Susceptibility was based predominantly on 2017 CLSI (Clinical and Laboratory Standards Institute) breakpoints. Isolates were categorized as multidrug-resistant (MDR: resistant to ≥ 1 antimicrobial in ≥ 3 out of 16 antimicrobial categories) or extensively drug-resistant (XDR: resistant to ≥ 1 antimicrobial in all but ≤ 2 out of 16 antimicrobial categories) based on expert consensus criteria for Enterobacteriaceae (European CDC (ECDC)/CDC, 2012). We collapsed antimicrobial categories described by the ECDC/CDC consensus group into 9 categories: penicillins, cephalosporins, monobactam, carbapenems, protein synthesis inhibitors, fluoroquinolones, folate pathway inhibitors, fosfomycin, and colistin. Biofilm formation was assessed using a modified crystal violet method (OD570) and defined by tertile cut-points. Antimicrobial resistance was compared for weak (n=47) versus strong (n=46) biofilm formation by chi-square or Fisher’s exact test. Predictors of strong biofilm formation were identified using logistic regression.

    Results: MDR isolates were more common among weak (n=46/47, 97.9%) versus strong biofilm formers (n=35/46, 76.1%; p=0.002), whereas XDR was similar between groups (n=12/47, 25.5% vs. n=13/46, 28.3% p=0.77). Resistance to penicillins, cephalosporins, monobactams, carbapenems, protein synthesis, or fluoroquinolones were more common among weak biofilm formers (p<0.05). Carbapenem resistance was inversely associated with strong biofilm formation (odds ratio 0.09; 95% confidence interval 0.02-0.33).

    Conclusion: Carbapenem resistant K. pneumoniae were 91% less likely to form strong biofilm. Potential trade-off mechanisms between antimicrobial resistance and biofilm formation require further exploration.

    Jaclyn Cusumano, PharmD1,2, Kathryn Daffinee, BS2, Megan Luther, Pharm.D.1,2, Vrishali Lopes, MS2, Aisling Caffrey, PhD, MS1,2,3 and Kerry LaPlante, Pharm.D., FCCP, FIDSA1,2,3,4, (1)College of Pharmacy, University of Rhode Island, Kingston, RI, (2)Providence Veterans Affairs Medical Center, Providence, RI, (3)Center of Innovation in Long-Term Support Services, Providence Veterans Affairs Medical Center, Providence, RI, (4)Division of Infectious Diseases, Warren Alpert Medical School of Brown University, Providence, RI


    J. Cusumano, None

    K. Daffinee, None

    M. Luther, None

    V. Lopes, None

    A. Caffrey, Merck: Grant Investigator , Research grant . The Medicine's Company: Grant Investigator , Research grant . Pfizer: Grant Investigator , Research grant .

    K. LaPlante, Merck: Grant Investigator , Research grant . Pfizer Pharmaceuticals: Grant Investigator , Research grant . Allergan: Scientific Advisor , Honorarium . Ocean Spray Cranberries, Inc.: Grant Investigator and Scientific Advisor , Honorarium and Research grant . Achaogen, Inc.: Scientific Advisor , Honorarium . Zavante Therapeutics, Inc.: Scientific Advisor , Honorarium .

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.