Abstract: The invention relates to antimicrobial compositions comprising a combination of (1) a therapeutically effective amount of a compound of formula I ##STR1## with (2) a second ingredient selected from carbapenem antibiotics or with .beta.-lactamase inhibitors, to the use of the compositions for producing a medicament for the treatment and prophylaxis of infectious diseases, including MRSA infections, and to pharmaceutical compositions containing the combination.

Abstract: The present invention relates to compounds having the formula ##STR1## wherein X, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and R.sup.7 are as defined herein as well as readily hydrolyzable esters thereof, pharmaceutically acceptable salts of said compounds and hydrates of the compounds of formula I and of their esters and salts. These compounds have valuable pharmacological activity for the treatment and prophylaxis of infectious diseases, especially those caused by methicillin resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa.

Abstract: Compounds of formula I whereinR.sup.1 is hydrogen, lower alkyl which is unsubstituted or substituted by fluoro, aralkyl, cycloalkyl, --COR.sup.4 or --C(R.sup.5 R.sup.6)CO.sub.2 R.sup.7 --C(R.sup.5 R.sup.6)CONHR.sup.7 ; where R.sup.5 and R.sup.6 are each independently hydrogen or lower alkyl, or R.sup.5 and R.sup.6 taken together form a cycloalkyl group; R.sup.4 is hydrogen or lower alkyl and R.sup.7 is hydrogen, lower alkyl, lower alkenyl or a carboxylic acid protecting group;R.sup.2 is hydrogen, hydroxy, lower alkyl-Q.sub.m, cycloalkyl, lower alkoxy, lower alkenyl, cycloalkenyl, lower alkynyl, aralkyl-Q.sub.m, aryl-Q.sub.

Abstract: Compounds of formula I ##STR1## wherein R.sup.1 is hydrogen, lower alkyl, cycloalkyl or acetyl;x is CH or N;n is 0, 1 or 2;m is 0 or 1;R.sup.2 is hydrogen, lower alkyl, .omega.-hydroxy alkyl, benzyl or lower alkyl-heterocyclyl, the benzyl and the heterocyclyl group being unsubstituted or substituted with at least one of the groups amino, cyano, carboxy, halogen, hydroxy, lower alkyl, lower alkoxy or --CONR.sub.2, where R is hydrogen or lower alkyl; or R.sup.2 is --CH.sub.2 CONR.sup.4 R.sup.5 ; whereinR.sup.4, R.sup.5 are each independently hydrogen, .omega.-hydroxy-alkyl, phenyl, benzyl, naphthyl or heterocyclyl, the phenyl, benzyl, naphthyl or heterocyclyl groups being unsubstituted or substituted with at least one of the groups optionally protected hydroxy, halogen, optionally substituted lower alkyl, optionally substituted lower alkoxy, .omega.-hydroxyalkyl or cyano; or R.sup.4 and R.sup.