The options available for treating infections with carbapenemase-producing <italic>
<named-content content-type="family">
<ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://doi.org/10.1601/nm.3091" xlink:type="simple">Enterobacteriaceae</ext-link>
</named-content>
</italic> (CPE) are limited; with the increasing threat of these infections, new treatments are urgently needed. Biapenem (BIPM) is a carbapenem, and limited data confirming its <italic>in vitro</italic> killing effect against CPE are available. In this study, we examined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of BIPM for 14 IMP-1-producing <italic>
<named-content content-type="family">
<ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://doi.org/10.1601/nm.3091" xlink:type="simple">Enterobacteriaceae</ext-link>
</named-content>
</italic> strains isolated from the Okayama region in Japan. The MICs against almost all the isolates were lower than 0.5 µg ml⁻¹, indicating susceptibility to BIPM, while approximately half of the isolates were confirmed to be bacteriostatic to BIPM. However, initial killing to a 99.9 % reduction was observed in seven out of eight strains in a time–kill assay. Despite the small data set, we concluded that the <italic>in vitro</italic> efficacy of BIPM suggests that the drug could be a new therapeutic option against infection with IMP-producing CPE.