2044. In Vitro Activity of Omadacycline Against 14,000 Bacterial Isolates from the United States by Infection Type (2020-2021)

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Abstract Background Omadacycline (OMC) is a novel tetracycline class (aminomethylcycline) antibacterial FDA approved for treatment of acute bacterial skin and skin structure infection (ABSSSI) and community-acquired bacterial pneumonia (CABP) caused by indicated organisms. OMC is active against bacterial isolates expressing resistance to tetracycline, penicillin, fluoroquinolones, macrolides, and vancomycin. This study has been funded in whole or in part by Federal funds from the U.S. Department of Health and Human Services, Biomedical Advanced Research and Development Authority (BARDA) within the Office of the Assistant Secretary for Preparedness and Response, under Contract No. 75A50120C00001. Methods 14,000 bacterial clinical isolates were collected from 31 medical centers in the USA (2020-2021) in the SENTRY Surveillance Program. Isolates were collected from the following infection types: bloodstream (24.1%), pneumonia in hospitalized patients (22.6%), skin and skin structure (SSSI; 22.4%), urinary tract (15.9%), intraabdominal (5.5%), community acquired respiratory tract (8.3%) and other (1.2%). Identifications were confirmed by MALDI-TOF. Susceptibility testing of OMC and comparators was conducted according to CLSI M07 (2018) and M100 (2022) guidelines. OMC MIC results were interpreted using FDA breakpoints (BPs). Results OMC demonstrated potent in vitro activity against S. aureus (MIC90, 0.12 mg/L; 99.0% susceptible [S]) from SSSI, including 98.0% of MRSA (Table). From RTI, 99.6% of MSSA were S. 97.6% of S. lugdunensis and 95.5% of S. anginosus group isolates from SSSI were susceptible to OMC. All S. pyogenes and E. faecalis (including vancomycin-resistant [R]) isolates from SSSI were S to OMC. 99.8% of S. pneumoniae isolates from RTI were S to OMC, as were 100% of penicillin-R and tetracycline-R strains. H. influenzae susceptibility to OMC was 99.8%. Susceptibility of E. cloacae and K. pneumoniae isolates from all infection types to OMC was 88.9% and 90.4%, respectively. Conclusion OMC demonstrated potent in vitro activity against staphylococci, streptococci, E. faecalis, H. influenzae, E. cloacae, and K. pneumoniae isolates, including drug-resistant strains, regardless of infection type. Disclosures Michael D. Huband, BS, AbbVie: Grant/Research Support|Melinta: 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 Helio S. Sader, MD, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Pfizer: Grant/Research Support Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support.