The invention relates to novel chimeric antibiotics of formula (I) wherein R<;SUP>;1<;/SUP>; represents OH, OPO<;SUB>;3<;/SUB>;H<;SUB>;2<;/SUB>; or OCOR<;SUP>;5<;/SUP>;; R<;SUP>;2<;/SUP>; represents H, OH or OPO<;SUB>;3<;/SUB>;H<;SUB>;2<;/SUB>;; A represents N or CR<;SUP>;6<;/SUP>;; R<;SUP>;3 <;/SUP>; represents H or fluorine; R<;SUP>;4<;/SUP>; is H, (C<;SUB>;1<;/SUB>;-C<;SUB>;3<;/SUB>;) alkyl, or cycloalkyl; R<;SUP>;5<;/SUP>; is the residue of a naturally occurring amino acid, of the enantiomer of a naturally occurring amino acid or of dimethylaminoglycine; R<;SUP>;6<;/SUP>; represents H, alkoxy or halogen; and n is O or 1; and to salts (in particular pharmaceutically acceptable salts) of compounds of formula (I). These chimeric compounds are useful in the manufacture of medicaments for the treatment of infections (e.g. bacterial infections).本發明係關於式I之新穎嵌合抗生素:;I,;其中:;R1表示OH、OPO3H2或OCOR5;R2表示H、OH或OPO3H2;A表示N或CR6;R3表示H或氟;R4為H、(C1-C3)烷基或環烷基;R5為天然存在胺基酸之殘基、天然存在胺基酸之對映異構體之殘基或二甲基胺基甘胺酸之殘基;R6表示H、烷氧基或鹵素;且n為0或1;且係關於式I化合物之鹽(尤其為醫藥學上可接受之鹽)。;該等嵌合化合物適用於製造用於治療感染(例如細菌感染)之藥劑。