A carbapenem compound of the formula (I) wherein: R is 1-hydroxyethyl, 1-fluoroethyl or hydroxymethyl; R is hydrogen or C1-4alkyl; R is hydrogen or C1-4alkyl; R is hydroxy or carboxy; and the phenyl ring is optionally further substituted by one or two substitutents selected from halo, cyano, C1-4alkyl, nitro, hydroxy, carboxy, C1-4alkoxy, trifluoromethyl, C1-4alkoxycarbonyl, carbamoyl, C1-4alkylcarbamoyl, di-C1-4alkylcarbamoyl, amino, C1-4alkylamino, di-C1-4alkylamino, sulphonic acid, C1-4alkylS(O)n- (wherein n is 0-2), N-C1-4alkanesulphonamido, C1-4alkanoylamino and C1-4alkanoyl(N-C1-4alkyl)amino: provided that the phenyl ring is substituted by at least one carboxy; or a pharmaceutically acceptable salt or in vivo hydrolysable ester thereof.