1226. In Vitro Activity of Tebipenem and Comparators Against Enterobacterales Collected from Patients with Bloodstream Infections as Part of the 2019 Global STEWARD Surveillance Program

Background Bloodstream infections (BSI) are a significant cause of morbidity and mortality. Enterobacterales (ENT) are frequently implicated in BSI with an increase in organisms producing extended-spectrum β-lactamase (ESBL). This challenges a possible transition to current oral agents due to co-resistance. Carbapenems are active against ESBL-ENT and tebipenem (TBP) is a new oral carbapenem in clinical development. The aim of the study was to assess resistance (R) among BSI isolates and activity of TBP and comparators against ENT collected in a 2019 surveillance study. Methods 2612 ENT from BSI were centrally tested by reference broth microdilution. Isolates were from medical centers in the US, Europe (EU), Latin America (LA) and Asia Pacific (AP). MIC results were interpreted according to CLSI, including ESBL assignment. CRE were sequenced to identify carbapenemase genes. Results Among the ENT, non-susceptibility (NS) rates to ceftazidime, levofloxacin were 20.4 and 27.0%, respectively, and R to trimethoprim-sulfamethoxazole was 31.1%. NS rates for ertapenem (ETP) and MER were 4.9 and 2.7%, respectively. MIC90s for TBP, ETP and MER were 0.12, 0.12 and 0.06 µg/mL, respectively. The MIC90 for TBP was 0.06 µg/mL for ENT from the US and 0.12 µg/mL for isolates from EU, LA and AP. Escherichia coli (EC) was the most prevalent (52% of ENT isolates) and the MIC90 for TBP ranged from 0.015 µg/mL for isolates in the US/EU to 0.03 µg/mL for isolates in LA/AP. ESBL-EC ranged from 15.7% in US to 34.3% in LA. TBP was active against ESBL-EC with an MIC90 of 0.03 µg/mL. Klebsiella pneumoniae (KP) accounted for 22.7% of BSI caused by ENT and TBP MIC90 ranged from 0.06 µg/mL for KP in US to >8 µg/mL in EU, LA and AP. MER-R KP ranged from 2.4% in US to 14.9% in LA. KPC-2, -3 and NDM were the most prevalent carbapenemases. TBP MIC90 values for MER-S ESBL KP in EU, LA and AP were ≤0.12 µg/mL. Conclusion TBP activity was similar to ETP and MER against ENT responsible for BSI. R to oral agents was compromised by ESBL co-resistance. TBP was among the most active agents against EC isolates and ESBL phenotypes. Among KP, TBP was more active against isolates from US where prevalence of CRE was lower than EU, LA and AP. TBP may be considered as an alternative oral option for BSI caused by non-CRE ESBL-producing ENT. Disclosures Ian A. Critchley, Ph.D., Spero Therapeutics (Employee, Shareholder) Nicole Cotroneo, Spero Therapeutics (Employee, Shareholder) Rodrigo E. Mendes, PhD, AbbVie (Research Grant or Support)AbbVie (formerly Allergan) (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)ContraFect Corporation (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support)