Abstract: An antibacterial 3-vic-dihydroxyaroylmethylpyridiniothiomethyl cephalosporin (I) and its salts represented by the following formula: ##STR1## (wherein, R.sup.1 is amino group or acylamino; R.sup.2 is hydrogen or methoxy; R.sup.3 is hydrogen atom or substituent; R.sup.4 is vic-dihydroxyaryl; R.sup.5 is straight or branched lower alkylene; R.sup.6 is hydrogen, a carboxy-protecting group or combined with Y a negative charge; X is --O--, --S-- or sulfinyl; and Y is a counter-ion of pyridinio or combined with R.sup.6 a negative charge),a disinfecting and treating method of bacterial infection using it, and synthetic methods thereof are provided.

Abstract: An antibacterial, 7.beta.-[(Z)-2-(2-aminothiazol-4-yl)-4-carboxybut-2-enoylamino]-3-cephem-4 -carboxylic acid is stable in a (di or tri)-hydrate crystal form. A pharmacologically effective amount of this hydrate is filled in a gelatin hard capsule and sealed by a band of gelatin to make a stable composition for clinical use after storage for a long time.

Abstract: An antibacterial, 7.beta.-[(Z)-2-(2-aminothiazol-4-yl)-4-carboxybut-2-enoylamino]-3-cephem-4 -carboxylic acid is stable in a (di or tri)-hydrate crystal form. A pharmacologically effective amount of this hydrate is filled in a gelatin hard capsule and sealed by a band of gelatin to make a stable composition for clinical use after storage for a long time.

Abstract: An antibacterial, 7.beta.-[(Z)-2-(2-aminothiazol-4-yl)-4-carboxybut-2-enoylamino]-3-cephem-4 -carboxylic acid is stable in a (di or tri)-hydrate crystal form. A pharmacologically effective amount of this hydrate is filled in a gelatin hard capsule sealed by a band of gelatin to make a stable composition for clinical use after storage for a long time.

Abstract: An antibacterial 3-(alkylcarbamoyloxymethyl)-3-cephem-4-carboxylic acid or its derivatives represented by the following formula ##STR1## (wherein R is hydrogen or an amino-protecting group,R.sup.1 and R.sup.2 each is the same or different 1C to 8C alkyl,R.sup.3 is hydrogen, a salt or ester forming atom or group, andX is sulfur or sulfinyl),a pharmaceutical composition containing the same, a method for treating a bacterial infection with the same, and a method for preparing the same are disclosed.

Abstract: An oral antibacterial, 7beta-[(Z)-2-(2-aminothiazol-4-yl)-2-alkenoylamino]-3-cephem-4-carboxylic acid pharmaceutically acceptable ester represented by the following formula: ##STR1## (wherein R is amino or protected amino,R.sup.1 is straight, branched, or cyclic alkyl optionally substituted by alkoxy,R.sup.2 is hydrogen or a 3-substitutent of cephalosporins,R.sup.3 is a pharmaceutically acceptable ester group, andX is sulfur or sulfinyl).

Abstract: Antibacterial 7.beta.-(oxo-saturated heterocyclic carbonamido)-3-cephem-4-carboxylic acid derivatives of the formula: ##STR1## (wherein R is hydrogen or methoxy; R.sup.1 is hydrogen or a nucleophilic group; R.sup.2 is hydrogen, light metal, or a carboxy protecting group; X is oxygen, sulfur, sulfinyl, or sulfonyl; Y is alkylene containing one or more hetero atoms; and Z is hydrogen or a substituent).