Molecular analysis of an antibiotic resistance plasmid, pAV5, and its derivative plasmids in Acinetobacter calcoaceticus

The non-conjugative plasmid pAV5 specifies resistance to kanamycin/neomycin (KmR) and tetracycline (TcR). Physical evidence is presented to show that pAV5 gives rise to two plasmids, pAV51 (KmR) and pAV52 (TcR), which are formed by deletion of apparently non-overlapping segments of pAV5. Expression of TcR has been obtained in Escherichia coli and is associated with a 1.9 kb HindIII fragment found in pAV5 and in pAV52. Expression of KmR has been obtained in E. coli and is associated with a 1.3 kb PstI fragment found in pAV5 and pAV51. Evidence is presented that the KmR gene is flanked by inverted repeat sequences and is therefore tentatively identified as a transposon, designated Tn4411. The KmR gene specifies an aminoglycoside 3'-phosphotransferase-type I (APH(3')-I) enzyme.