In vitro activity of flomoxef and comparators against Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis producing extended-spectrum β-lactamases in China.

•We performed a multicentre nationwide surveillance to investigate the activity of flomoxef.•Flomoxef showed good activity against extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae.•blaCTX-M was the major ESBL gene in ESBL-producing Enterobacteriaceae in China.•Cefotaxime and cefepime showed very low activities against ESBL-producing isolates.•This study is the first report of the prevalence of CTX-M-65 in clinical Proteus mirabilis isolates in China.