The nucleotide sequence of a 1.25 kb BglII/EcoRI fragment from the 34 kb trimethoprim (Tp)-resistant plasmid pABU1 of Staphylococcus aureus 157/4696, isolated in Zürich, was determined. It contained the entire Tp-resistant dihydrofolate reductase gene, 197 bp of the thymidylate synthetase, 395 bp of a truncated gene and 111 bp of IS257R1. With the exception of one single base pair at position 862 the sequence of the whole fragment was identical to nucleotides 1633 to 2885 of the Tp-resistant transposon Tn4OO3 in plasmid pSK 1 from an Australian S. aureus isolate. This suggests the worldwide dissemination of Tn4OO3 in multiresistant Staphylococci.
