A compound or its pharmaceutically acceptable salt represented by the
following formula: ##STR00001## The invention is a carbapenem compound
which has a potent antibacterial activity over a broad range of Gram
negative and Gram positive bacteria, especially penicillin-resistant
Streptococcus pneumoniae (PRSP) which has been isolated at an elevated
frequency in recent years and thus causes a serious clinical problem, and
Haemophilus influenzae which has acquired resistance against the existing
.beta.-lactam antibiotics over a wide scope due to penicillin-binding
protein (PBP) mutations such as .beta.-lactamase non-producing
ampicillin-resistant (BLNAR) Haemophilus influenzae, and has excellent
oral absorbability.