1260. Activity of Manogepix (APX001A) against 2,669 Fungal Isolates from the SENTRY Surveillance Program (2018-2019) Stratified by Infection Type

Abstract Background Existing antifungal agents are active against many common fungal pathogens; however, breakthrough fungal infections occur and often involve less frequently encountered yeast and mould isolates. These rarer isolates tend to exhibit diminished susceptibility to current agents. Manogepix (MGX, APX001A) is a novel inhibitor of the fungal Gwt1 enzyme. The prodrug (fosmanogepix), is being evaluated in Phase 2 clinical trials for invasive candidiasis/candidemia, Candida auris infections, and invasive aspergillosis. In this study, we evaluated the in vitro activity of MGX and comparators against 2,669 clinical fungal isolates collected worldwide (2018-2019) and stratified by infection type. Methods Fungal isolates were collected from medical centers located in North America (34 sites; 42.3%), Europe (30 sites; 37.9%), Asia-Pacific (11 sites; 12.3%), and Latin America (7 sites; 7.6%). Isolates were collected from bloodstream infections (BSI; 51.7%), pneumonia in hospitalized patients (PIHP; 21.1%), skin and skin structure infections (SSSI; 5.5%), urinary tract infections (UTI; 2.3%), intraabdominal infections (IAI; 1.9%), and other infection types (17.5%). Results MGX demonstrated potent in vitro activity against 1,887 Candida spp. isolates from BSI, PIHP, SSSI, and all infection types (MIC50/90, 0.008/0.03-0.06 mg/L) outperforming all comparator agents (Table). Similarly, MGX was equally active against 578 Aspergillus spp. isolates (MEC50/90, 0.015/0.03 mg/L), regardless of infection type. MGX was active against Cryptococcus neoformans var. grubii isolates from BSI and ALL infection types with MIC50/90 values of 0.5/2 mg/L. Scedosporium spp. isolates from PIHP and all infection types were inhibited by low concentrations of MGX (MEC50/90, 0.03/0.03 mg/L). Table 1 Conclusion MGX demonstrated potent antifungal activity against Candida spp., Aspergillus spp., C. neoformans var. grubii, and non-Aspergillus moulds, including Scedosporium spp. isolates. Notable activity was seen against C. auris, echinocandin-resistant Candida spp., azole-resistant Aspergillus, and Scedosporium spp. isolates. Further clinical development of fosmanogepix in difficult-to-treat resistant fungal infections is warranted. Disclosures Michael A. Pfaller, MD, Amplyx Pharmaceuticals (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Robert K. Flamm, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support) Shawn A. Messer, PhD, Amplyx Pharmaceuticals (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support) Beth A. Schaefer, n/a, Amplyx Pharmaceuticals (Research Grant or Support) Paul Bien, MS, Amplyx Pharmaceuticals (Employee) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support)

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1258. Activity of a Series of Investigational Compounds Tested Against Invasive Fungal Isolates

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.1442 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S645-S646

Author(s):

Paul R Rhomberg ◽

Shawn A Messer ◽

Richard W Scott ◽

Simon D P Baugh ◽

Michael A Pfaller ◽

...

Keyword(s):

Fungal Infections ◽

Chemical Diversity ◽

Candida Auris ◽

Services Research ◽

Defense Proteins ◽

Fungal Isolates ◽

Wide Range ◽

Cryptococcus Spp ◽

Center Research ◽

Research Grant

Abstract Background Fox Chase Chemical Diversity Center (FCC) is developing non-peptide analogs of host defense proteins for the treatment of invasive fungal infections mainly caused by Candida (CAN) and Aspergillus (ASP). We evaluated the activity of 6 novel compounds and 2 comparators against 150 isolates from 15 fungal groups. Methods Susceptibility testing was performed per CLSI broth microdilution methods for investigational compounds and comparators against 70 CAN and 40 ASP isolates in addition to 10 Cryptococcus spp. (CRYP), 10 Fusarium spp. (FUS), 10 Mucorales, and 10 Scedosporium spp. (SCED) isolates from recent (2017-2019) clinical infections. MIC results were determined as ≥ 50% reduction at 24 and 72 hours for CAN and CRYP respectively, and 100% reduction at 24, 72, and 48 hours for Mucorales, SCED, and other moulds, respectively. CLSI clinical breakpoint (CBP) and epidemiological cutoff value (ECV) interpretive criteria were applied for comparators. Results Compounds FC10790, FC11083, FC11212, and FC11275 had MIC50 results at ≤ 0.015 mg/L and MIC90 results at ≤ 0.015 to 0.12 mg/L against CRYP, ASP, and FUS isolates. Compounds FC5096 and FC11022 were 2- to 4-fold less active while demonstrating MIC50 and MIC90 results of 0.03 to 0.5 mg/L against CAN, CRYP, ASP, and FUS isolates. The Mucorales isolate set showed the widest range of MIC results for FC compounds. FC10790 exhibited the greatest potency with a MIC50/90 at 0.5/2 mg/L. FC compounds showed potent activity against SCED with MIC90 results of 0.03 to 0.25 mg/L. Fluconazole showed a wide range of MIC results, from 0.06 to >64 mg/L, but the highest results observed were for Candida auris (MIC50/90, 64/ > 64 mg/L) and Candida krusei (MIC50/90; 16/32 mg/L). Itraconazole was active against all ASP (MIC50/90, 1/1 mg/L), but showed poor activity against FUS (MIC50/90, > 8/ > 8 mg/L). Amphotericin B showed a narrow range of MIC results (0.5 to 2 mg/L) for all isolates except 1 ASP and most SCED. Conclusion Novel FCC compounds showed equal or greater activity than comparators against most CAN, ASP, SCED, and FUS. FC10790, FC11212, and FC11275 showed the greatest activity against all tested fungal isolates. development of this series of compounds for clinical studies. Table 1 Disclosures Paul R. Rhomberg, n/a, Cidara Therapeutics (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Merck (Research Grant or Support) Shawn A. Messer, PhD, Amplyx Pharmaceuticals (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support) Richard W. Scott, PhD, Fox Chase Chemical Diversity Center (Employee) Simon DP Baugh, PhD, Fox Chase Chemical Diversity Center (Employee) Michael A. Pfaller, MD, Amplyx Pharmaceuticals (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support) Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support)

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1443. Activity of Ceftazidime-Avibactam against Carbapemenase-negative Carbapenem-resistant Enterobacterales (CRE) Isolates from US Hospitals

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.1624 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S725-S725

Author(s):

Mariana Castanheira ◽

Timothy B Doyle ◽

Cory Hubler ◽

Rodrigo E Mendes ◽

Helio S Sader

Keyword(s):

Resistance Mechanisms ◽

Chemical Diversity ◽

Services Research ◽

New Agents ◽

E Coli ◽

Department Of Health ◽

Carbapenem Resistant ◽

Center Research ◽

Research Grant

Abstract Background Most CRE isolates in US hospitals produce KPC enzymes, but some do not carry carbapenemases. We investigated the prevalence, resistance mechanisms and activity of ceftazidime-avibactam and comparator agents against CRE that did not carry carbapenemase genes from US hospitals. Additionally, meropenem-resistant isolates were tested for meropenem-vaborbactam. Methods A total of 28,904 Enterobacterales isolates were collected in 70 US hospitals during 2016-2018, and susceptibility tested by reference broth microdilution. Meropenem-vaborbactam was tested using lyophilized panels following the manufacturer’s instructions. CRE isolates were submitted to whole genome sequencing for the screening of b-lactamase genes, multilocus sequence typing, changes in outer membrane protein (OMP) genes and AmpC expression levels. Results A total of 304 (1.1%) CREs were observed in the study period and 45 (14.8%) isolates did not carry carbapenemases. These isolates were mainly Klebsiella aerogenes, Enterobacter cloacae and Klebsiella pneumoniae (11, 11 and 10 isolates, respectively), but also included 5 other species. Acquired b-lactamase genes were detected among 17 isolates and blaCTX-M-15 was the most common (13 isolates). All K. aerogenes and 10 E. cloacae did not carry acquired b-lactamase genes. Ceftazidime-avibactam (100% susceptible) inhibited all isolates at the current breakpoint, followed by tigecycline and amikacin (> 80% susceptible). Other comparators were not active against non-carbapenemase-producing CRE. Nine of 35 meropenem-resistant isolates displayed meropenem-vaborbactam MIC values of ≥ 8 mg/L (nonsusceptible). Further analysis showed that 23 isolates had disruption of OmpC/OmpK36, 4 had disrupted OmpF/OmpK35 and 13 had both OMP genes disrupted. Additionally, 7 isolates had elevated AmpC expression among 17 isolates tested. Among 7 E. coli, 4 were ST131 and only 2 of 10 K. pneumoniae were clonal complex 11. Conclusion Therapy options for treatment of infections caused by CRE were very limited until recent approval of new agents with activity against these isolates. Ceftazidime-avibactam demonstrated full in vitro activity against all carbapenemase-negative CRE carrying multiple resistance mechanisms. Disclosures Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support) Timothy B. Doyle, Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support) Cory Hubler, Allergan (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)

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1253. In Vitro Activity of Omadacycline against 7000 Bacterial Pathogens from the United States Stratified by Infection Type (2019)

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.1437 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S644-S644

Author(s):

Michael D Huband ◽

Michael A Pfaller ◽

Jennifer M Streit ◽

Helio S Sader ◽

Mariana Castanheira

Keyword(s):

United States ◽

The United States ◽

Chemical Diversity ◽

Vitro Activity ◽

Multiple Infection ◽

In Vitro Activity ◽

Infection Types ◽

Center Research ◽

Research Grant

Abstract Background Omadacycline (OMC) is a new aminomethylcycline antibacterial drug belonging to the tetracycline class, for intravenous or oral administration. It is well tolerated and has proven effective in the treatment of a variety of bacterial infections. OMC is active against bacterial strains expressing the most common clinically relevant tetracycline resistance mechanisms, namely efflux and ribosomal protection. Methods 7,000 clinical isolates were collected during 2019 in the SENTRY Surveillance Program from 31 medical centers in the United States (US). Isolates were obtained from bloodstream infection (23.8%), skin and skin structure infection (21.6%), pneumonia in hospitalized patients (22.7%), urinary tract infection (14.5%), intraabdominal infection (6.2%), community acquired respiratory tract infection (10.3%) and other infection types (0.9%). Identifications were confirmed by MALDI-TOF. One isolate/patient/infection episode was tested. Broth microdilution susceptibility testing was conducted according to CLSI M07 (2018) and M100 (2020) guidelines. Results were interpreted using US FDA and CLSI breakpoint criteria. Results OMC demonstrated potent in vitro activity against Staphylococcus aureus isolates representing multiple infection types (MIC90, 0.12-0.25 mg/L; 94.7%-99.0% susceptible [S]) including MRSA (MIC90, 0.25 mg/L; 96.5% S) (Table). All S. lugdunensis (MIC90, 0.06 mg/L), Enterococcus faecalis (MIC90, 0.12-0.25 mg/L), and Haemophilus influenzae (MIC90, 1 mg/L) isolates were S to OMC. OMC was active against Streptococcus pyogenes isolates from SSSI (MIC90, 0.12 mg/L; 93.3%-98.5%S) including macrolide-resistant (R) strains. Similarly, S. pneumoniae isolates from RTI were S to OMC (MIC90, 0.06-0.12 mg/L; 98.8%-100%S) regardless of resistance to tetracycline or penicillin. Overall, 90.2%-93.6% of Enterobacter cloacae (MIC90, 4 mg/L) and 89.7%-94.7% of Klebsiella pneumoniae (MIC90, 4-8 mg/L) isolates from multiple infection types were S to OMC. Conclusion OMC demonstrated potent in vitro activity against Gram-positive and -negative bacterial pathogens from multiple infection types including SSSI and RTI and isolates displaying resistance to tetracycline, macrolides, and penicillin. Table 1 Disclosures Michael A. Pfaller, MD, Amplyx Pharmaceuticals (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support)

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1629. Vancomycin Resistance in Enterococcus faecium Clinical Isolates Responsible for Bloodstream Infections in US Hospitals Over Ten Years (2010-2019) and Activity of Oritavancin

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.1809 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S806-S807

Author(s):

Cecilia G Carvalhaes ◽

Helio S Sader ◽

Jennifer M Streit ◽

Mariana Castanheira ◽

Rodrigo E Mendes

Keyword(s):

Enterococcus Faecium ◽

Bloodstream Infections ◽

Chemical Diversity ◽

Intrinsic Resistance ◽

Services Research ◽

Vana Gene ◽

Department Of Health ◽

Common Phenotype ◽

Center Research ◽

Research Grant

Abstract Background Enterococcus faecium (EFM) causes difficult-to-treat infections due to its intrinsic resistance (R) and ability to acquire R to many antimicrobials. This study evaluated the vancomycin (VAN)-R rates over time and the activity of oritavancin (ORI) against a collection of EFM causing bloodstream infections (BSI). Methods A total of 1,081 BSI EFM isolates collected from 36 US hospitals in a prevalence mode design during 2010-2019 were evaluated. Bacterial identification was confirmed by MALDI-TOF MS. Susceptibility testing was performed by reference broth microdilution. For comparison, the ORI breakpoint for VAN-susceptible E. faecalis was applied to EFM. Isolates were characterized as VanA or VanB phenotypes based on their susceptibility (S) to VAN and teicoplanin (TEC). The VanB phenotype was confirmed by PCR and/or whole genome sequencing. Results Overall, 72.3% (782/1,081) of EFM were VAN-R (Table). VanA was the most common phenotype (97.7%; 764/782). The yearly VAN-R rates decreased from 81.8% in 2010 to 58.7% in 2019. A total of 18 (2.3%) isolates exhibited a VanB phenotype (TEC MIC, 0.5-8 mg/L); however, the vanB gene only was confirmed in 9 EFM isolates (TEC MIC, 0.5-1 mg/L), which were all collected in 2010-2012. The remaining 9 (50.0%) VanB phenotype EFM isolates carried a vanA gene (TEC MIC, 4-8 mg/L). ORI was very active against VAN-susceptible EFM (MIC50/90, ≤ 0.008/≤0.008/mg/L), VanA (MIC50/90, 0.03/0.12 mg/L; MIC100, 0.5 mg/L), and VanB (MIC50/90, ≤ 0.008/0.015 mg/L; MIC100, 0.03 mg/L) subsets. Only linezolid (LZD) and ORI (MIC, ≤ 0.12 mg/L) showed > 95.0%S against EFM and VAN-R subsets. Daptomycin (DAP)-R rarely was observed (0.8%), but it was more frequently found in the last 5 years. However, 49.9% of EFM isolates showed elevated DAP MICs (2 and 4 mg/L). ORI inhibited 77.8%, and 100.0% of DAP-R and LZD-nonsusceptible EFM isolates at ≤ 0.12 mg/L, respectively. Conclusion VAN-R rates among EFM causing BSI in the US decreased during 2010-2019. VanA remains the most common phenotype, whereas vanB-carrying isolates became rarer in later years. Interestingly, half of VanB-phenotype isolates carried a vanA gene. ORI was very active against EFM causing BSI, including isolates R to VAN, DAP, and/or nonsusceptible to LZD. Table 1 Disclosures Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)

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1376. Antifungal Activity of Cerium Nitrate Against Fungal Isolates Associated with Combat-Related Injuries Including Burns

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.1207 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S422-S422

Author(s):

Heather Pomerantz ◽

Miriam Beckius ◽

Dana Blyth ◽

Kevin S Akers ◽

David R Tribble ◽

...

Keyword(s):

Fungal Infections ◽

Mucor Circinelloides ◽

Cerium Nitrate ◽

Time Dependent ◽

Candida Spp ◽

Burn Care ◽

Fungal Isolates ◽

Time Kill ◽

Slow Growing

Abstract Background Fungal infections are a critical cause of morbidity and mortality in burn patients. In addition to debridement and systemic antifungal therapy, various topical adjuncts have been used, and topical burn care is a key component of infection prevention and treatment. Cerium nitrate (CN) has been used in combination with silver sulfadiazine (SS) in burn care. Previous studies showed that CN had bacteriostatic activity, and suggested anti-biofilm activity against Candida biofilms. In this study, we evaluated the in vitro activity of CN against fungal isolates associated with combat-related injuries. Methods The efficacy of CN was evaluated against 14 mold (three Aspergillus spp., two Fusarium spp., five different mucormycetes, two Bipolaris spp., one Alternaria spp., one Exophiala spp.) and 21 Candida spp. isolates collected as part of the Trauma Infectious Disease Outcomes Study. Fungicidal activity of various concentrations of CN (2.2%, 1%, 0.5% and 0.2%) was determined using an established time-kill assay. Standard conidia/cell suspensions were prepared according to Clinical and Laboratory Standards Institute guidelines and then exposed to the CN solutions for 24 hours. At different times (0, 5, 15, 30 minutes, 1, 1.5, 3, 6, 12, and 24 hours) aliquots were plated and incubated at 35ºC. Colony forming unit (CFU) counts were determined after 24 hours incubation or after an appropriate time for slow growing molds. Results All mold isolates had persistent growth at 24 hours with most having no significant change in colony counts over the 24-hour period. The only exception was Mucor circinelloides, which appeared to have a time-dependent reduction in CFUs at 24 hours for all CN concentrations. Exophiala did not grow as well in CN solutions compared with the control (mean 65 vs. 28.2 CFUs with a difference of mean 37.4 CFUs, P = 0.0001), but this was not time or concentration dependent. All yeast species showed a time-dependent killing after 6–12 hours. Conclusion CN demonstrated time-dependent killing of the yeasts. However, very little activity was observed against the tested molds. Since CN is often used in combination with SS there might be a synergistic effect against molds. Further research will evaluate higher concentrations of CN and its toxicity for cells and tissue. Disclosures All authors: No reported disclosures.

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2115. Activity of a Long-Acting Echinocandin Rezafungin and Comparator Antifungal Agents Tested against Contemporary Invasive Fungal Isolates: SENTRY 2018

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.1795 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S716-S716 ◽

Cited By ~ 1

Author(s):

Michael A Pfaller ◽

Cecilia G Carvalhaes ◽

Shawn A Messer ◽

Paul R Rhomberg ◽

Mariana Castanheira

Keyword(s):

Drug Exposure ◽

Fungal Infections ◽

Hot Spot ◽

Good Activity ◽

Candida Spp ◽

Fluconazole Resistance ◽

Fungal Isolates ◽

Long Acting ◽

In Vitro Data

Abstract Background Echinocandins are the first-line treatment of candidemia. We evaluated the activity of rezafungin (RZF), a novel long-acting echinocandin with front-loaded drug exposure and extensive distribution to sites of infection, and comparators using CLSI broth microdilution methods against 709 invasive fungal isolates collected worldwide during 2018. Methods Susceptibility (S) tests on 663 Candida spp. (6 species), 21 C. neoformans (CNEO), and 25 A. fumigatus (ASF) were conducted for RZF, anidulafungin (ANF), caspofungin (CSF), micafungin (MCF), and azoles. CLSI clinical breakpoint (CBP) and epidemiological cutoff value (ECV) interpretive criteria were applied. Isolates displaying echinocandin MIC>ECV were sequenced for fks hot spot (HS) mutations. Results RZF inhibited 99.7% of C. albicans (CA) isolates (MIC50/90, 0.015/0.06 mg/L), 100.0% of C. tropicalis (CT) (MIC50/90, 0.03/0.06 mg/L), 98.9% of C. glabrata (CG) (MIC50/90, 0.03/0.06 mg/L), 100.0% of C. krusei (CK) (MIC50/90, 0.015/0.12 mg/L), and 100.0% of C. dubliniensis (CD) (MIC50/90, 0.03/0.06 mg/L) at ≤0.12 mg/L. All (104/104 [100.0%]) C. parapsilosis (CP) isolates (MIC50/90,1/2 mg/L) were inhibited by RZF at ≤2 mg/L. Fluconazole resistance was detected among 9.0% of CG, 17.3% of CP, and 1.6% of CT. The activity of RZF against these 6 Candida spp. was similar to that of the other echinocandins, the vast majority of which were susceptible/wild type (WT) using CBP/ECV. A total of 5 isolates (3 CG, 1 CA, and 1 CT) displayed 1 or more non-WT or-resistant MIC values and were sequenced for fks HS mutations. Fluconazole and other azoles displayed good activity against CNEO whereas echinocandins including RZF displayed limited activity against CNEO isolates. Echinocandins displayed good activity against ASF, and RZF activity was similar to that of anidulafungin, caspofungin, and micafungin. All but 1 isolate (non-WT MIC for itraconazole, 2 mg/L) displayed WT MIC values for the mould-active azoles. Conclusion Rezafungin was as active as other echinocandins against common organisms recovered from invasive fungal infections. These in vitro data contribute to accumulating research demonstrating rezafungin potential for prevention and treatment of invasive fungal infection. Disclosures All authors: No reported disclosures.

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327. Oritavancin Activity against Staphylococcus aureus Isolates Causing Bone and Joint Infections in European Hospitals (2010–2019)

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.523 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S235-S236

Author(s):

Cecilia G Carvalhaes ◽

Jennifer M Streit ◽

Helio S Sader ◽

Rodrigo E Mendes

Keyword(s):

Staphylococcus Aureus ◽

Western Europe ◽

Methicillin Resistance ◽

Chemical Diversity ◽

Surveillance Program ◽

Services Research ◽

Joint Infections ◽

Bone And Joint Infections ◽

Research Grant

Abstract Background Bone and joint infections (BJI) frequently are caused by Staphylococcus aureus (SA), and since prolonged therapy courses typically are required, agents with convenient administration are preferred. Oritavancin (ORI) is a long-acting lipoglycopeptide approved as a single dose regimen for treating skin and skin structure infections. This study evaluates the activity of ORI and comparators against SA causing BJI in European (EU) hospitals. Methods A total of 575 SA isolates from the SENTRY Antimicrobial Surveillance Program causing BJI in 15 EU countries from 2010 to 2019 were included. Bacterial identification was confirmed by MALDI-TOF MS. Broth microdilution susceptibility (S) testing and interpretation was performed following current CLSI guidelines. The activities of ORI and comparators were evaluated across the years and by EU region: western Europe (W-EU; 491 isolates) and eastern EU/Mediterranean region (E-EU; 84 isolates). Results Methicillin resistance (MRSA) was observed in 20.5% of SA (18.5% in W-EU and 32.1% in E-EU), ranging from 31.1% in 2011 to 14.6% in 2016. MRSA rates were slightly lower in 2016–2019 (14.6%-19.2%) than previous years (2011–2013; 24.4%-31.1%). ORI exhibited 100.0% susceptibility across the entire SA collection with yearly MIC50 and MIC90 variations within 1 doubling dilutions (MIC50 and MIC90, 0.015–0.03 and 0.03–0.06 mg/L, respectively), regardless the MRSA phenotype or EU region. Daptomycin, vancomycin, teicoplanin, and linezolid also showed complete coverage against SA. Clindamycin (CLI; >99.0%S) and levofloxacin (> 95.0%S) were active against methicillin-susceptible SA, but less active against MRSA (67.8%S and 16.1%S, respectively). E-EU MRSA isolates displayed lower S rates than W-EU MRSA isolates to ceftaroline (83.3% vs. 90.6%), CLI (44.4% vs. 74.7%) and tetracycline (66.7% vs. 89.0%), respectively. Conclusion MRSA rates among isolates causing BJI varied within regions. Although several drugs were in vitro active against MSSA, options remained limited against MRSA. ORI showed in vitro activity against the entire collection of European SA isolates and may be a consideration for treating BJI with the convenience of drug administration. Table 1 Disclosures Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)

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Antimicrobial Activity of Ceftazidime-Avibactam and Comparator Agents Tested against Enterobacteriaceae and Pseudomonas aeruginosa from United States (US) Medical Centers Stratified by Infection Type (2015–2016)

Open Forum Infectious Diseases ◽

10.1093/ofid/ofx163.933 ◽

2017 ◽

Vol 4 (suppl_1) ◽

pp. S378-S378

Author(s):

Helio S Sader ◽

Mariana Castanheira ◽

Leonard R Duncan ◽

Robert K Flamm

Keyword(s):

Infection Type ◽

Broth Microdilution ◽

Large Collection ◽

Skin Structure ◽

Highly Active ◽

Medical Centers ◽

Carbapenem Resistant ◽

Infection Types ◽

Research Grant

Abstract Background We evaluated and compared the in vitro activities of ceftazidime-avibactam (CAZ-AVI) and comparators against of Enterobacteriaceae (ENT) and P. aeruginosa (PSA) from various infection types. Methods 23,440 isolates composed of 19,249 ENT and 4,191 PSA were consecutively collected from 85 US hospitals and tested for susceptibility (S) by broth microdilution methods in a central monitoring laboratory (JMI Laboratories). The antimicrobial S and frequency of key resistance (R) phenotypes, such as multidrug-R (MDR) and extensively drug-R (XDR) among others, were assessed and stratified by these infection types: bloodstream (BSI; 3,434 isolates; 14.7%), pneumonia (6,439; 27.5%), skin/skin structure (SSSI; 4,134; 17.6%), intra-abdominal (IAI; 951; 4.1%), urinary tract (UTI; 7,873; 33.6%), and others combined (609; 2.6%). Results CAZ-AVI was active against 99.9% to 100.0% of ENT and 97.0% (pneumonia) to 99.4% (UTI) of PSA isolates. S rates were consistently lower among ENT from pneumonia compared with other infection types for β-lactams such as CAZ (82.3% vs. 87.1–90.8%), piperacillin-tazobactam (P-T; 87.5% vs. 90.2–95.6%) and meropenem (MEM; 96.8% vs. 98.4–99.4%). S to gentamicin (GEN) was also generally lower among isolates from pneumonia, whereas S to levofloxacin (LEV) and colistin (COL) were lowest among BSI and SSSI isolates, respectively. The occurrence of MDR, XDR, and carbapenem-resistant ENT (CRE) phenotypes were markedly higher among isolates from patients with pneumonia compared with other infection types (Table). Among PSA, S rates for CAZ, P-T, and GEN were lowest among isolates from pneumonia, whereas S to MEM was similar among isolates from BSI, pneumonia, and IAI (77.3–77.9%), and S to LEV was markedly lower among UTI isolates (67.1%). The frequency of PSA isolates with MDR and XDR phenotypes, as well as non-S to CAZ, MER, and P-T, were also highest among isolates from patients with pneumonia (Table). Conclusion Antimicrobial S rates were generally lower among ENT and PSA isolates from patients with pneumonia compared with other infections. CAZ-AVI was highly active against a large collection of contemporary ENT and PSA isolates from US hospitals (2015–2016), including MDR and XDR organisms, regardless of the infection type. Disclosures H. S. Sader, Allergan: Research Contractor, Research grant; M. Castanheira, Allergan: Research Contractor, Research grant; L. R. Duncan, Allergan: Research Contractor, Research grant; R. K. Flamm, Allergan: Research Contractor, Research grant

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1547. Activity of Tedizolid and Comparator Agents against Gram-Positive Bacterial Isolates Causing Skin and Skin Structure Infections in Pediatric Patients during 2015-2019 in the US

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.1727 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S773-S773

Author(s):

Cecilia G Carvalhaes ◽

Helio S Sader ◽

Paul R Rhomberg ◽

Mariana Castanheira ◽

Rodrigo E Mendes

Keyword(s):

Pediatric Patients ◽

Chemical Diversity ◽

Services Research ◽

Coagulase Negative Staphylococci ◽

Gram Positive ◽

Skin Structure ◽

Broth Microdilution Method ◽

The Us ◽

Center Research ◽

Research Grant

Abstract Background New strategies to treat acute bacterial skin and skin structure infections (ABSSSI) are needed due to the spread of methicillin-resistant Staphylococcus aureus (MRSA), a common multidrug resistant pathogen of ABSSSIs. Tedizolid (TZD) was approved by the US FDA for treating ABSSSI in adults and is under evaluation for treating pediatric patients. Accordingly, the activity of TZD and comparators was evaluated against clinical surveillance isolates collected from pediatric patients with SSSI in the US. Methods A total of 2,758 Gram-positive isolates were collected from pediatric patients with SSSIs in 33 sites in the US between 2015 and 2019 as part of the Surveillance of Tedizolid Activity and Resistance (STAR) Program. Bacterial identification was confirmed by MALDI-TOF MS and susceptibility (S) testing performed by the CLSI reference broth microdilution method. Current CLSI interpretative criteria was applied. Results S. aureus (SA; n=2,163; 78.4%) was the most frequent pathogen recovered from all age groups (≤ 1y; 2-5y; 6-12y; 13-17y), followed by β-hemolytic streptococci (BHS; n=460; 16.7%), and coagulase-negative staphylococci (CoNS; n=70; 2.5%). TZD was active against all SA (MIC50/90, 0.12/0.25 mg/L; 100% S). Equivalent TZD MIC50/90 values (0.12/0.25 mg/L) were observed against MRSA (n=886; 41.0%; MIC50/90, 0.12/0.25 mg/L) and methicillin susceptible (MSSA; MIC50/90, 0.12/0.25 mg/L) isolates, regardless the age group. TZD also was very active against BHS (MIC50/90, 0.12/0.25 mg/L; 100% S, regardless of species). TZD, linezolid, and daptomycin had 100.0% S rates against the main Gram-positive species and organism groups (Figure). Ceftaroline and clindamycin showed S rates of >90% against MRSA, MSSA, S. pyogenes and S. dysgalactiae. Lower S rates were observed for clindamycin against VGS (88.2%) and S. agalactiae (64.1%). TZD was the most potent agent (MIC90, 0.25 mg/L) against Enterococcus faecalis (n=30, 1.1%), and a vancomycin-resistance phenotype was observed in 1 (3.3%) isolate. Conclusion TZD was highly active against Gram-positive clinical isolates responsible for SSSI in pediatric patients across US hospitals from a 5-year period. TZD was equipotent or more potent than comparators against MSSA and MRSA isolates. Table 1 Disclosures Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Paul R. Rhomberg, n/a, Cidara Therapeutics (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Merck (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)

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1449. Frequency and Antimicrobial Susceptibility of Coagulase-Negative Staphylococcal (CoNS) Species Isolated from Clinical Specimens in United States and European Hospitals

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.1630 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S727-S727

Author(s):

Helio S Sader ◽

Cecilia G Carvalhaes ◽

Jennifer M Streit ◽

S J Ryan Arends ◽

Rodrigo E Mendes

Keyword(s):

United States ◽

Antimicrobial Susceptibility ◽

Bloodstream Infections ◽

The United States ◽

Common Species ◽

Chemical Diversity ◽

Services Research ◽

Clinically Significant ◽

Research Grant

Abstract Background CoNS represent an important cause of bloodstream infections, osteoarticular infections, foreign-body-associated infections and endocarditis. We evaluated the frequency of CoNS species and the activity of dalbavancin (DALB) in comparison to vancomycin (VAN), daptomycin (DAP) and other agents against a large collection of CoNS isolates. Methods 5,088 CoNS isolates causing clinically significant infection were consecutively collected from 122 medical centers located in the United States (79 centers) and Europe (43 centers in 21 nations) over 6 years (2014-2019) and susceptibility tested by CLSI broth microdilution methods against DALB and comparators. Species identification was confirmed by MALDI-TOF. Results Most isolates were from bloodstream (BSI; 53.5%) or skin/skin structure infections (28.5%). S. epidermidis was the most common species overall (54.6%; Table) and for BSI (61.3%). The second most common species were S. lugdunensis overall (12.3%) and S. hominis for BSI (14.7%). DALB (MIC50/90, 0.03/0.06 mg/L) inhibited > 99.9% of CoNS isolates at the susceptible (S) breakpoint established by CLSI for S. aureus (≤ 0.25 mg/L) and was 8-fold more active than DAP (MIC50/90, 0.25/0.5 mg/L; 99.9% S) and 32-fold more active than VAN (MIC50/90, 1/2 mg/L; > 99.9% S). Linezolid was active against 98.7% of isolates (MIC50/90, 0.5/1 mg/L). All species were inhibited at ≤0.25 mg/L of DALB, except S. epidermidis (> 99.9%) and S. warneri (98.9%; Table). The most DALB-S species were S. capitis and S. simulans (MIC50/90, 0.015/0.03 mg/L for both species), whereas the highest DALB MIC50/90 values were observed with S. haemolyticus and S. saprophyticus (MIC50/90, 0.06/0.12 mg/L and highest MIC of 0.25 mg/L for both species). In contrast, 47.8% of S. epidermidis and 34.7% S. haemolyticus exhibited decreased susceptibility to VAN (MIC ≥ 2 mg/L), and 23.2% of S. capitis and 28.4% of S. warneri showed decreased susceptibility to DAP (MIC ≥ 1 mg/L). Overall oxacillin-S rate was 39.3%, varying from 3.0% for S. saprophyticus to 95.4% for S. lugdunensis. In general, BSI isolates were slightly less S than non-BSI isolates. Conclusion Antimicrobial susceptibility varied widely among CoNS species. DALB exhibited potent in vitro activity against all CoNS species. Table 1 Disclosures Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) S. J. Ryan Arends, PhD, Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)

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