The present invention relates to a compound of formula (I) (wherein R.sup.1 and R.sup.2 represent an aryl group, a heterocyclic group, an alkyl group, an alkenyl group and the like which are optionally substituted, R.sup.3 represents a hydrogen atom or a hydroxyl group, and X.sup.1 and X.sup.2 represent an oxygen atom or a sulfur atom, or a nitrogen atom which may be substituted), a pharmaceutically acceptable derivative thereof or a salt thereof.The present invention also relates to a pharmaceutical composition comprising a compound described above as an active ingredient for the prevention or treatment of bacterial infections.The present invention includes the use of a compound described above in order to prepare a medicament effective in the prevention or treatment of bacterial infections.The present invention is concerned with a method for the prevention or treatment of bacterial infections in warm-blooded animals comprising administering a pharmacologically effective amount of a compound described above to them ##STR00001##