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
Authors: Lemos-Luengas Elkin , Rentería-Valoyes Sixta Romelia , Muñoz Diana Marcela Almario , Orozco Carlos David Gamboa , Gómez Juan Camilo Olivella , Ramos-Castaneda Jorge 
Published: November 2023

Abstract

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
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

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

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).

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