1594. Antimicrobial Resistance Monitoring through the ATLAS Global Surveillance Program 2012-2018

BACKGROUND: Antimicrobial resistance is an increasingly serious threat to global public health. The Antimicrobial Testing Leadership and Surveillance (ATLAS) program has provided reliable, global, regional and local in vitro susceptibility data, including mechanisms of resistance, since 2004. In this analysis, data from the ATLAS program are used to measure the in vitro activity of several key gram-negative/gram-positive agents against major global pathogens. METHODS: A total of 251,837 gram-negative and 132,363 gram-positive non-duplicate, clinical isolates were collected from multiple infection sources from 743 unique sites in 74 countries during 2012-2018 in the ATLAS program. Identification was confirmed to the species level using MALDI-TOF spectrometry. Only one clinically relevant causative isolate per patient was accepted into the study. MICs were determined by broth microdilution following CLSI guidelines and interpreted using 2020 CLSI breakpoints. Phenotypic ESBL screening and confirmatory testing were performed using the CLSI M100 method. RESULTS: The in vitro activities of selected antimicrobial agents are provided in the table below. Based on percent susceptibility, ceftazidime-avibactam, amikacin, tigecycline, meropenem, and ceftolozane-tazobactam were the most active agents against most gram-negative isolates. The CRE rate among Enterobacterales isolates was 3.2%, with tigecycline and ceftazidime-avibactam the most active among this resistant subgroup. Ceftazidime-avibactam, ceftolozane-tazobactam, and amikacin were the most active agents against Pseudomonas aeruginosa. Ceftaroline, linezolid, tigecycline and vancomycin all showed good activity against gram-positive isolates. Table [Image: see text] CONCLUSION: Ceftazidime-avibactam, ceftolozane-tazobactam, tigecycline, meropenem, and amikacin all showed good activity against a global collection of Enterobacterales. Ceftaroline, tigecycline, linezolid and vancomycin all exhibited excellent activity against gram-positive isolates. Continued monitoring of susceptibility patterns among common pathogens will provide useful information for determining treatment strategies. DISCLOSURES: Daniel F. Sahm, PhD, IHMA (Employee)Pfizer, Inc. (Consultant)Shionogi & Co., Ltd. (Independent Contractor) Michael Dowzicky, MS, M.T. A.S.C.P., Pfizer, Inc. (Employee)