2782. In vitro activity of ceftazidime-avibactam against Gram-negative strains in patients with bacteremia and skin and soft-tissue infections in Colombia 2019-2021

BACKGROUND: In vitro activity of Ceftazidime-avibactam (CAZ-AVI) in patients with bacteremia and skin and soft tissue infections (SSTIs) is unknown. The study aimed to analyze the in vitro antimicrobial activity of CAZ-AVI and other antimicrobials against Gram-negative bacilli collected in hospitals in Colombia in patients with bacteremia and SSTIs. METHODS: Enterobacterales and P. aeruginosa from patients with bacteremia and SSTIs were analyzed. Strains were collected from four ATLAS-reporting hospitals in Colombia between 2019 and 2021. RESULTS: Enterobacterales: A total of 600 Enterobacterales were collected. The most susceptible antimicrobials to Enterobacterales were CAZ-AVI (96.5%), tigecycline (95%), and amikacin (92.17%). The incidence of carbapenem-resistant Enterobacterales (CRE) was 13.5% (n= 81), and the antimicrobials with the best activity were tigecycline (93.83%), CAZ-AVI (74.07%), and amikacin (50.62%) (Figure 1). Tigecycline, CAZ-AVI, and amikacin were the antimicrobials with the best in vitro activity against MDR Enterobacterales, extended-spectrum β-lactamase-producing (ESBL) Enterobacterales, and KPC-producing Enterobacterales (Figure 2). K. pneumoniae (n= 198), E. coli (n= 167), Enterobacter cloacae (n= 46), and Serratia marcescens (n= 41) were the strains most frequently isolated (Table 1). Tigecycline and CAZ-AVI had excellent in vitro activity against all four species, as well as for those ESBL-producers, MDR, and carbapenem-resistant (CR). P. aerugniosa: A total of 259 P. aeruginosa were analyzed. CAZ-AVI was the antimicrobial with the best in vitro activity against P. aeruginosa with a susceptibility of 83.4%, as well as against CR (S= 44%), MDR (S= 50.58%), and DTR Pseudomonas (S= 33.33%). Figure 1 Antimicrobial activity among isolates of Enterobacterales and Carbapenem-resistant Enterobacterales (CRE) collected in Colombia between 2019 - 2021 [Figure: see text] S: susceptible; NS: Not susceptible; Pip/taz: Piperacillin-tazobactam; CZA: Ceftazidime-Avibactam; S: susceptible; NS: Not susceptible; CRE: Carbapenem-resistant Enterobacterales Figura 2 Not susceptibility among isolates of Extended-spectrum β-lactamase Enterobacterales, Multidrug-resistant Enterobacterales, Klebsiella pneumoniae carbapenemase (KPC)-producing enterobacterales, and metallo β-lactamase producing enterobacterales in Colombia [Figure: see text] A. Not susceptibility among isolates of Extended-spectrum β-lactamase enterobacterales (green color) and Multidrug-resistant Enterobacterales (orange color) B. Not susceptibility among Klebsiella pneumoniae carbapenemase (KPC)-producing enterobacterales (green color) and metallo β-lactamase producing enterobacterales (orange color) Pip/taz: Piperacillin-tazobactam; CZA: Ceftazidime-Avibactam; MDR: Multidrug-resistant [Figure: see text] CONCLUSION: Tigecycline and CAZ-AVI were the two antimicrobials with excellent in vitro activity against clinical specimens from patients with bacteremia and SSTIs caused by CRE, MDR Enterobacterales, and ESBL- and KPC-producing Enterobacterales. Against MDR, CR, and DTR P. aeruginosa, CAZ-AVI and amikacin were the antimicrobials with the best in vitro activity (Figure 3). [Figure: see text] DISCLOSURES: Elkin Lemos-Luengas, MD MSc PhD, Pfizer Colombia: Honoraria Sixta Romelia Rentería-Valoyes, Md, Pfizer: Senior Associate Medicines Business /Medical Scientific Liaison MD for Pfizer Colombia Diana Marcela Almario Muñoz, MD, MSc, Pfizer Colombia: Medical Scientific Liaison Carlos David Gamboa Orozco, Md, Pfizer: Medical Scientific Liaison for Pfizer Colombia Juan Camilo Olivella Gómez, n/a, Pfizer Colombia: Medical Student Jorge Ramos-Castaneda, PhD, Pfizer: Advisor/Consultant