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

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. [Figure: see text] 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 [Figure: see text] 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.