1230. In Vitro Activity of Cefiderocol against Multi-Drug Resistant Carbapenemase-Producing Gram-Negative Pathogens 
Session: Poster Abstract Session: Expanded Spectrum - New Antimicrobial Susceptibility Testing
Friday, October 6, 2017
Room: Poster Hall CD
Background: Few options remain for treatment of infections caused by multi-drug resistant (MDR), carbapenemase-producing gram-negative pathogens. Cefiderocol (CFDC; Shionogi & Co. Ltd), is a novel parenteral siderophore cephalosporin that enters the bacterial cell through the iron–siderophore uptake system. Here we report on the in vitro activity of CFDC against a set of well-characterized MDR gram-negative isolates collected by the Centers for Disease Control and Prevention.

Methods: Minimum inhibitory concentrations (MIC) values for CFDC in iron-depleted cation-adjusted Mueller Hinton broth were determined using reference broth microdilution. Study isolates (n=315) included Enterobacteriaceae (59%), Pseudomonas aeruginosa (19%), Acinetobacter baumannii (17%), Stenotrophomonas maltophilia (4%), and Burkholderia cepacia complex (1%). Of these, 229 (73%) were carbapenemase-producers including Ambler Class A- (37%), Class B- (29%) and Class D- type (29%) enzymes. The remaining isolates included 51 β-lactam-resistant isolates that were non-carbapenemase-producers, and 35 β-lactam-susceptible isolates. Results were interpreted using suggested CFDC breakpoints of Sensitive ≤4 μg/ml and Resistant ≥16 μg/ml.

Results: The majority of the isolates (90.8%) were categorized as CFDC susceptible; the percentage of isolates with a CFDC MIC ≤4 μg/ml among Enterobacteriaceae, P. aeruginosa, and A. baumannii was 87.5%, 100%, and 89%, respectively. Percentage of isolates with a CFDC MIC ≤4 μg/ml that harbored a carbapenemase of the Class A-, Class B-, and Class D-type was 91.8%, 74.8%, 98.0%, respectively. By applying suggested breakpoints, 12 isolates were categorized as intermediate and 17 as resistant. The resistant isolates included 11 NDM-, 2 OXA-23- and 4 KPC-positive organisms.

Conclusion: Cefiderocol showed potent activity against MDR gram-negative pathogens including Class A, B, and D carbapenemase-producing isolates. Of note, all P. aeruginosa, including Class B metallo-β-lactamase producers, were susceptible to CFDC.

Sandra Boyd, BS1, Karen Anderson, BS MT(ASCP)2, Valerie Albrecht, MPH3, Davina Campbell, MPH3, Maria S. Karlsson, PhD3 and J. Kamile Rasheed, PhD3, (1)Divsion of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, (2)Divsion of Healthcare Quality Promotion, CDC, Atlanta, GA, (3)Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA

Disclosures:

S. Boyd, None

K. Anderson, None

V. Albrecht, None

D. Campbell, None

M. S. Karlsson, None

J. K. Rasheed, None

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