Tn2001, a transposon encoding chloramphenicol resistance in Pseudomonas aeruginosa

Abstract

A new transposon, Tn2001, was isolated from the group P-2 plasmid Rms159-1 in P. aeruginosa. Tn2001-encoded chloramphenicol resistance did not result from the formation of chloramphenicol acetyltransferase. Tn2001 was transposable between temperate phages and conjugative and nonconjugative plasmids belonging to various incompatibility groups, including P-1, P-3, P-4, P-5, P-7 and P-8 in P. aeruginosa. Transposition occurred independently of the general recombination ability of the Pseudomonas host, and its frequency varied between 10-1 and 10-8, depending on the donor and recipient replicons. Tn2001 transposition also occurred in a recombination-deficient strain of Escherichia coli. Agarose gel elctrophoresis and EM observations revealed that Tn2001 could transpose to different sites in the RP4 replicon and that the transposed DNA fragment was 2.1 kilobases long.