1580 - In Vitro Activity of Ceftazidime-Avibactam Against Enterobacterales and Pseudomonas aeruginosa Collected in Latin America as part of the ATLAS Global Surveillance Program, 2017-2019

Background: Ceftazidime-avibactam (CAZ-AVI) is a β-lactam/non-β-lactam β-lactamase inhibitor combination with in vitro activity against Enterobacterales (Ent) and Pseudomonas aeruginosa (Psa) carrying Class A, C and some Class D β-lactamases. We examined the in vitro activity of CAZ-AVI and comparators against isolates collected in Latin America (LA) as part of the ATLAS surveillance program.

Methods: Non-duplicate isolates of Ent (n=8416) and Psa (n=2521) were collected in 10 countries in Central America (CAC; Costa Rica, Dominican Republic, Guatemala, Panama [2018-2019 only]) and South America (SA; Argentina, Brazil, Chile, Colombia, Mexico, Venezuela [2017-2019]). Susceptibility testing was performed by CLSI broth microdilution and values were interpreted using CLSI 2020 breakpoints. CAZ-AVI was tested at a fixed concentration of 4 µg/mL AVI. Isolates with meropenem (MEM) MICs ≥2 µg/mL (Ent) or ≥4 µg/mL (Psa) were screened for β-lactamase genes.

Results: CAZ-AVI demonstrated potent in vitro activity against Ent collected in LA overall and in the CAC and SA subregions (95-99% susceptible (S)) that was comparable to or exceeded the activity of comparators including MEM, amikacin (AMK) and tigecycline (TGC) (Table). CAZ-AVI retained good activity against MEM non-susceptible (NS) Ent collected in SA (82% S; 6.9% of collected isolates) but activity was reduced against MEM-NS Ent from CAC (10% S; 5.7% of collected isolates), which included a high proportion of isolates carrying NDM-type metallo-β-lactamases (MBL). Among Psa, CAZ-AVI showed greater activity than the tested comparators against both all (86-92% S) and MEM-NS (61-66% S) isolates collected in LA overall and in the two subregions.Table


Conclusion: CAZ-AVI showed potent in vitro activity against Ent and Psa collected from patients in the CAC and SA subregions of LA. Activity was also good against MEM-NS isolates from SA but was reduced against MEM-NS Ent from CAC that included a high proportion of MBL-positive isolates. The regional and country prevalence of different carbapenem-resistance mechanisms must be considered when evaluating treatment options; however, CAZ-AVI could provide a valuable therapeutic option for treatment of infections caused by Ent and Psa in LA.