New molecular variants of epsilon and beta IncP-1 plasmids are present in estuarine waters

Abstract

In this work the presence of broad-host-plasmids in an estuary in Portugal has been inves- tigated. Pseudomonas putida KT2442 was used as model recipient bacteria in biparental matings with tetracycline and mercury to select for resistance phenotypes. As a result, 7 transconjugants were shown to carry broad-host-plasmids from the IncP-1 group, as seen by PCR amplification of the trfA gene. Sequence analysis confirmed the isolation of 4 plas- mids from b -1 subgroup and 3 assigned to the recently described e subgroup. To our knowledge this is the first report concerning the detection and isolation of IncP-1 b and e plasmids in estuarine waters. Moreover it is shown that, even though the retrieved plas- mids are phylogenetically close to previously characterized plasmids, such as pB10 and pKJK5, respectively, they constitute new molecular variants.