Which non-carbapenem antibiotics are active against extended-spectrum β-lactamase-producing Enterobacteriaceae?

In this study, the activity of 18 non-carbapenem antibiotics was evaluated against 100 extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-Ec) and 50 ESBL-producing Klebsiella pneumoniae (ESBL-Kp) isolated from urinary tract infections and bacteraemia in 2016. Minimum inhibitory concentrations (MICs) were determined using reference methods and the susceptibility profiles were defined according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) 2017 recommendations. All of the ESBL-Ec isolates were susceptible to ceftazidime/avibactam and a great majority of them were susceptible to fosfomycin (98%), piperacillin/tazobactam (97%), amikacin (97%) and nitrofurantoin (96%). Mecillinam, cefoxitin and ceftolozane/tazobactam remained active against 92%, 83% and 78% of the ESBL-Ec isolates, respectively. Moreover, 100%, 94% and 90% of the ESBL-Kp tested were susceptible to ceftazidime/avibactam, amikacin and mecillinam, respectively. This study showed that there are non-carbapenem options (including orally administrable drugs) for the treatment of all of the situations of ESBL-Ec or ESBL-Kp infections, with ceftazidime/avibactam being the most efficient alternative.