2-Ethenylthio-type carbapenem derivatives of formula (I) or pharmaceutically acceptable salts thereof are provided. The compounds according to the present invention have potent antimicrobial activity and a wide antimicrobial spectrum against pneumococci including penicillin resistant
Streptococcus pneumoniae
(PRSP),
Haemophilus influenzae
including β-lactamase-negative, ampicillin-resistant
Haemophilus influenzae
(BLNAR), and
Moraxella
(
Branhamella
)
catarrhalis
.