In vitro activity of ceftazidime/avibactam and comparators against carbapenemase-producing Enterobacterales and Pseudomonas aeruginosa isolates collected globally between 2016 and 2018

Objectives This study reports antimicrobial activity for ceftazidime-avibactam and comparators against carbapenemase-producing Enterobacterales (N = 1,992) and carbapenemase-producing Pseudomonas aeruginosa (N = 784) collected in Africa/Middle East, Asia/South Pacific, Europe and Latin America (2016-2018). Methods MICs and susceptibility were determined using broth microdilution methodology and EUCAST breakpoints. Genes encoding carbapenemases were detected using multiplex PCR assays. Results No isolates of carbapenemase-producing, MBL-negative Enterobacterales from Africa/Middle East or Latin America were resistant to ceftazidime-avibactam; resistance rates in Europe and Asia/South Pacific were ≤ 4.5%. Colistin had the lowest resistance rate among MBL-positive isolates (6.0%-11.4%). Enterobacterales isolates collected in Latin America predominantly carried a KPC carbapenemase (77.6%), whereas in Africa/Middle East OXA-48-like carbapenemases were most frequently detected (55.9%), and in Asia/South Pacific most isolates carried NDM carbapenemases (56.2%). Among all Enterobacterales carrying KPC carbapenemases, the lowest rate of resistance was to ceftazidime-avibactam (1.5%), and among isolates carrying NDM carbapenemases, to colistin (10.8%). Among carbapenemase-producing, MBL-negative P. aeruginosa, resistance rates to ceftazidime-avibactam were 8.6% for isolates collected in Europe and 53.2% in Latin America. Isolates in each region most frequently carried VIM carbapenemases, ranging from 41.7% of isolates in Asia/South Pacific to 86.2% in Africa/Middle East. No P. aeruginosa carrying KPC or NDM carbapenemases, and 1.0% of isolates carrying GES carbapenemases, were resistant to colistin. Conclusion Given the limited therapeutic options to treat infections caused by carbapenemase-positive Enterobacterales and P. aeruginosa, continued surveillance of ceftazidime-avibactam activity, as well as that of agents such as colistin, is crucial.