1734. Susceptibility of Cefiderocol between US Census Regions against Gram-Negative Organisms collected from the SENTRY Surveillance Program: 2020-2021

Abstract Background Cefiderocol (CFDC) is a siderophore-conjugated cephalosporin with broad activity against Gram-negative (GN) bacteria, including multidrug-resistant organisms. GN bacteria such as Enterobacterales (ENT), Pseudomonas aeruginosa (PsA), Acinetobacter baumannii complex (ABC), and Stenotrophomonas maltophilia (StM) can be challenging to treat and are often carbapenem-resistant (CR). Regional susceptibility of CFDC and comparators were investigated against US GN isolates collected in 2020-2021 as part of the SENTRY Antimicrobial Surveillance Program. Methods GN pathogens were consecutively collected from 32 US hospitals between 2020 to 2021. Susceptibility testing was performed using the broth microdilution method. CFDC was tested in iron-depleted cation-adjusted Mueller-Hinton broth. FDA or CLSI breakpoints were used where available. Other agents tested included the beta-lactam/beta-lactamase inhibitor (BL/BLI) combinations ceftazidime-avibactam, ceftolozane-tazobactam, imipenem-relebactam, meropenem-vaborbactam, piperacillin-tazobactam, and ampicillin-sulbactam. CR-PsA, or CRAB was defined as meropenem resistant while CRE was defined as imipenem or meropenem resistant by CLSI breakpoints. Results A total of 8328 ENT, 2241 PsA, 586 ABC, and 404 StM were collected. For ENT and PsA, CFDC susceptibility between the 9 US Census regions remained above 98% susceptible by CLSI or FDA breakpoints in all regions (Table 1). Amongst the BL/BLI combinations, the majority had >90% susceptibility across regions except for piperacillin-tazobactam with 79.7% for ENT and 65.9% for PsA in the MidAtlantic by FDA breakpoints. For ABC and StM, CFDC susceptibility was > 88% across all regions. For CR pathogens, 96 CRE, 327 CR-PsA, and 199 CRAB were collected. CFDC had >87.5% susceptibility in all regions for CRE and CR-PSA. For CRAB, 4 regions were > 87.5% by FDA breakpoints and the lowest was 63.6% in 11 isolates in the Mountain region (Table 2). For CRAB, every BL/BLI had susceptibility ≤27.3% in every region. Ampicillin-sulbactam had 27.3% susceptibility in the Mountain region. Table 1 Susceptibility of Cefiderocol against Enterobacterales, Pseudomonas aeruginosa, Acinetobacter baumannii complex and Stenotrophomonas maltiphilia isolates in the cefiderocol program collected from medical centers in the USA Table 2: Susceptibility of cefiderocol against CRE, CR Pseudomonas aeruginosa, and CR Acinetobacter baumannii complex isolates in the cefiderocol program collected from medical centers in the USA Conclusion US GN isolates, including CR pathogens, had high susceptibilities to CFDC across the US census regions. CFDC remains an important treatment option for GN infections in all US census regions. Disclosures Frank H. Kung, PhD, Shionogi Inc: Employee Sean Nguyen, n/a, Shionogi: Employee Christine M. Slover, PharmD, Shionogi: Employee Dee Shortridge, PhD, AbbVie: Grant/Research Support|JMI Laboratory: Employee|Melinta: Grant/Research Support|Menarini: Grant/Research Support|Shionogi: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Roger Echols, MD, Shionogi: Advisor/Consultant Roger Echols, MD, Shionogi: Advisor/Consultant Roger Echols, MD, Shionogi: Advisor/Consultant Miki Takemura, n/a, Shionogi: Employee Yoshinori Yamano, PhD, Shionogi: Employee.