A compound having the formula: ##STR1## wherein R is a straight chain or branched chain lower alkyl, cyclic lower alkyl, lower alkenyl (except for 1-carboxy-1-vinyl), lower alkynyl, aralkyl, phenyl or 2-pyrrolidon-3-yl group which may be substituted, and Q is ##STR2## (wherein R.sup.1 is a hydrogen atom or an acetyl group, R.sup.2 is a hydrogen atom, a carboxyl group or a carboxymethyl group, Y is a sulfur atom or an oxygen atom, Z is a sulfur atom, an oxygen atom or an imino group which may be substituted by a lower alkyl group); or a pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.