Abstract: Novel cephem derivatives represented by the general formula ##STR1## in which the Acyl substituent is a group of the formula ##STR2## wherein Ar is a lipophilic optionally substituted phenyl, naphthyl or pyridyl group; R.sup.1 represents either the residue of a heterocyclic amino acid or a C.sub.2 -C.sub.10 alkyl group substituted by both a carboxyl group and a group of the formula --NR.sup.9 R.sup.10 or ##STR3## in which R.sup.9 and R.sup.10 are each independently hydrogen or C.sub.1 -C.sub.6 alkyl, said C.sub.2 -C.sub.10 alkyl group being optionally interrupted by one or more nitrogen atoms or carbonyl groups, and R.sup.2 and R.sup.3 are each independently hydrogen, alkyl or aminoalkyl are gram-positive antibacterial agents, especially useful in the treatment of diseases caused by methicillin-resistant Staphylococcus aureus (also referred to below as MRSA or methicillin-resistant S. aureus).

Abstract: Novel cephem derivatives represented by the general formula ##STR1## in which the Acyl substituent is a group of the formula ##STR2## wherein Ar is a lipophilic optionally substituted phenyl, naphthyl, pyridyl or benzthiazolyl group; R.sup.1 is selected from certain optionally substituted aliphatic, aromatic, arylaliphatic or sugar moieties and R.sup.2 and R.sup.3 are each independently hydrogen, alkyl or aminoalkylcarbonylamino are gram-positive antibacterial agents, especially useful in the treatment of infectious diseases caused by methicillin-resistant Staphylococcus aureus (MRSA).

Abstract: Novel cephem derivatives represented by the general formula ##STR1## in which the Acyl substituent is a group of the formula ##STR2## wherein Ar is a lipophilic optionally substituted phenyl, naphthyl or pyridyl group; R.sup.1 represents either the residue of a heterocyclic amino acid or a C.sub.2 -C.sub.10 alkyl group substituted by both a carboxyl group and a group of the formula --NR.sup.9 R.sup.10 or ##STR3## in which R.sup.9 and R.sup.10 are each independently hydrogen or C.sub.1 -C.sub.6 alkyl, said C.sub.2 -C.sub.10 alkyl group being optionally interrupted by one or more nitrogen atoms or carbonyl groups, and R.sup.2 and R.sup.3 are each independently hydrogen, alkyl or aminoalkyl are gram-positive antibacterial agents, especially useful in the treatment of diseases caused by methicillin-resistant Staphylococcus aureus (also referred to below as MRSA or methicillin-resistant S. aureus).

Abstract: Novel cephem derivatives represented by the general formula ##STR1## in which the Acyl substituent is a group of the formula ##STR2## wherein Ar is a lipophilic optionally substituted phenyl, naphthyl, pyridyl or benzthiazolyl group; R.sup.1 is selected from certain optionally substituted aliphatic, aromatic, arylaliphatic or sugar moieties and R.sup.2 and R.sup.3 are each independently hydrogen, alkyl or aminoalkylcarbonylamino are gram-positive antibacterial agents, especially useful in the treatment of infectious diseases caused by methicillin-resistant Staphylococcus aureus (MRSA).

Abstract: Novel cephem derivatives represented by the general formula ##STR1## in which the Acyl substituent is a group of the formula ##STR2## where Ar is a substituted phenyl or optionally substituted naphthyl or benzthiazolyl group and A is a substituted-pyridinium group are gram-positive antibiotics, especially useful in the treatment of diseases caused by methicillin-resistant Staphylococcus aureus.

Abstract: Disclosed are novel carbapenem derivatives characterized by a 2-substituent of the formula ##STR1## in which A represents cyclopentylene, cyclohexylene or C.sub.2 -C.sub.6 alkylene optionally substituted by one or more C.sub.1 -C.sub.4 alkyl groups and ##STR2## represents a quaternized nitrogen-containing aromatic heterocycle. Such derivatives are useful as potent antibacterial agents. Also disclosed are processes for the preparation of such derivatives and novel intermediates utilized in these processes.

Abstract: Disclosed are novel carbapenem derivatives characterized by a 2-substituent of the formula ##STR1## in which A represents cyclopentylene, cyclohexylene or C.sub.2 -C.sub.6 alkylene optionally substituted by one or more C.sub.1 -C.sub.4 alkyl groups; R.sup.5 represents either (a) an optionally substituted aliphatic, cycloaliphatic, cycloaliphatic-aliphatic, aryl, araliphatic, heteroaryl, heteroaraliphatic, heterocyclyl or heterocyclyl-aliphatic radical or (b) a divalent phenylene or C.sub.1 -C.sub.4 alkylene group joined to the ##STR2## ring so as to form a bridged polycyclic group; and ##STR3## represents a quaternized nitrogen-containing non-aromatic heterocycle. Such derivatives are useful as potent antibacterial agents.

Abstract: Disclosed are novel carbapenem derivatives characterized by a 2-substituent of the formula ##STR1## in which A represents cyclopentylene, cyclohexylene or C.sub.2 -C.sub.6 alkylene optionally substituted by one or more C.sub.1 -C.sub.4 alkyl groups and ##STR2## represents a quaternized nitrogen-containing aromatic heterocycle. Such derivatives are useful as potent antibacterial agents. Also disclosed are processes for the preparation of such derivatives and novel intermediates utilized in these processes.

Abstract: Disclosed are novel carbapenem derivatives characterized by a 2-substituent of the formula ##STR1## in which A represents cyclopentylene, cyclohexylene or C.sub.2 -C.sub.6 alkylene optionally substituted by one or more C.sub.1 -C.sub.4 alkyl groups; R.sup.5 represents either (a) an optionally substituted aliphatic, cycloaliphatic, cycloaliphatic-aliphatic, aryl, araliphatic, heteroaryl, heteroaraliphatic, heterocyclyl or heterocyclyl-aliphatic radical or (b) a divalent phenylene or C.sub.1 -C.sub.4 alkylene group joined to the ##STR2## ring so as to form a bridged polycyclic group; and ##STR3## represents a quaternized nitrogen-containing non-aromatic heterocycle. Such derivatives are useful as potent antibacterial agents.

Abstract: Disclosed are novel carbapenem derivatives characterized by a 2-substituent of the formula ##STR1## in which A represents cyclopentylene, cyclohexylene or C.sub.2 -C.sub.6 alkylene optionally substituted by one or more C.sub.1 -C.sub.4 alkyl groups and ##STR2## represents a quaternized nitrogen-containing aromatic heterocycle. Such derivatives are useful as potent antibacterial agents. Also disclosed are processes for the preparation of such derivatives and novel intermediates utilized in these processes.