Meiji Seika Kaisha, Ltd.

Ryoichi Okamoto

Shinichi Kondo

Takashi Yoshida

Takashi Tsuruoka

Katsuyoshi Iwamatsu

Kiyoaki Katano

Masaji Sezaki

Hiroko Ogino

Shigeharu Inoue

Fumio Kai

Cephalosporin compounds represented by the following formula (I) and pharmaceutically acceptable salts thereof have a broad bactericidal spectrum against various pathogenic bacteria including Psuedomonas aeruginosa and are useful as bactericidal remedies for pathogenic diseases of human and animals: ##STR1## wherein A represents an unsubstituted or substituted pyridylthio group of a formula (I-1); ##STR2## or an unsubstituted or substituted pyridiniumthio group of a formula (I-2): ##STR3## or an unsubstituted or substituted pyridinium group of a formula (I-3); ##STR4## or a 5- or 6-membered heterocyclicthio or bicycloheterocyclicthio group of a formula (I-4):

Cephalosporin derivatives and bactericides containing the same

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Chiba, Japan

Ryoichi Okamoto