Abstract: A compound represented by the following general formula (I) or a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutical composition thereof, and the use thereof to prevent or treat infectious diseases and a method to prevent or treat infectious diseases using those regimen are disclosed. The compound represented by formula (I) has an antibacterial activity against both gram-positive and gram-negative bacteria, and is useful in the prevention or treatment of infectious diseases caused by these bacteria.

Abstract: A compound represented by the following general formula (I) or a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutical composition thereof, and the use thereof to prevent or treat infectious diseases and a method to prevent or treat infectious diseases using those regimen are disclosed. The compound represented by formula (I) has an antibacterial activity against both gram-positive and gram-negative bacteria, and is useful in the prevention or treatment of infectious diseases caused by these bacteria.

Abstract: A compound represented by the following general formula (I) or a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutical composition thereof, and the use thereof to prevent or treat infectious diseases and a method to prevent or treat infectious diseases using those regimen are disclosed. The compound represented by formula (I) has an antibacterial activity against both gram-positive and gram-negative bacteria, and is useful in the prevention or treatment of infectious diseases caused by these bacteria.

Abstract: A compound represented by the following general formula (I) or a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutical composition thereof, and the use thereof to prevent or treat infectious diseases and a method to prevent or treat infectious diseases using those regimen are disclosed. The compound represented by formula (I) has an antibacterial activity against both gram-positive and gram-negative bacteria, and is useful in the prevention or treatment of infectious diseases caused by these bacteria.

Abstract: A compound represented by the following general formula (I) or a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutical composition thereof, and the use thereof to prevent or treat infectious diseases and a method to prevent or treat infectious diseases using those regimen are disclosed. The compound represented by formula (I) has an antibacterial activity against both gram-positive and gram-negative bacteria, and is useful in the prevention or treatment of infectious diseases caused by these bacteria.

Abstract: Compounds, represented by the following formula (I), having a .beta.-(substituted or unsubstituted imidazo?5,1-b!thiazolyl)vinyl group at the 3-position of the cephem ring and a salt and an ester thereof are disclosed. The compounds have antibacterial activity against a very wide spectrum of bacteria and potent antibacterial activity against Gram-positive bacteria, Gram-negative bacteria, and resistant bacteria. ##STR1## wherein X represents CH or N, R.sup.1 represents a hydrogen atom or an amino protective group, R.sup.2 represents a hydrogen atom, a C.sub.1-6 alkyl group, a C.sub.3-7 cycloalkyl group, or a hydroxy protective group, R.sup.3 is absent or represents a hydrogen atom, a salt forming cation, or a carboxyl protective group, R.sup.4, R.sup.5, and R.sup.6, which may be the same or different, each independently represent a hydrogen atom or a C.sub.1-6 alkyl group, R.sup.7+ is absent or a cation of a C.sub.1-6 alkyl, and n is an integer of 0 to 1.

Abstract: Compounds represented by the following formula (I), that is, cephem derivatives having substituted or unsubstituted imidazo[5,1-b]thiazolium-6-yl as a substituent at the 3-position of the cephem ring: ##STR1## wherein X represents CH or N, R.sup.1 represents H, alkyl, alkenyl or the like, and R.sup.2, R.sup.3, R.sup.4 and R.sup.5 represent H, alkyl, carbamoyl, amino or the like. The above compounds have excellent antibacterial activity, and useful as medicines for the treatment of various infectious diseases caused by bacteria.

Abstract: As new compounds are now synthetized 5-deoxy-5,5-difluoro derivatives of aminoglycosidic antibiotics of neamine, kanamycin A-series, kanamycin B-series, gentamicin-series and seldomycin-series. Further, the 1-N-(.alpha.-hydroxy-.omega.-aminoalkanoyl) derivatives are synthetized from 5-deoxy-5,5-difluorokanamycins A and B, as well as their analogues now obtained. The 5-deoxy-5,5-difluoro derivatives of the aminoglycosidic antibiotics now provided according to this invention have such antibacterial activities enhanced much more than or equal to those of the respectively corresponding parent aminoglycosidic antibiotics, while these 5-deoxy-5,5-difluoro derivatives exhibit values of the 50% lethal dosage (LD.sub.50) which are improved remarkably better when they are intravenously administered to mice, so that they have remarkedly reduced toxicities to mammals.