The ancient small mobilizable plasmid pALWED1.8 harboring a new variant of the non-cassette streptomycin/spectinomycin resistance gene aadA27

Publication date: Available online 16 February 2016 Source:Plasmid Author(s): Anton Kurakov, Sofia Mindlin, Alexey Beletsky, Natalya Shcherbatova, Andrey Rakitin, Aleksandra Ermakova, Andrey Mardanov, Mayya Petrova The small mobilizable plasmid pALWED1.8 containing a novel variant of the streptomycin/spectinomycin resistance gene aadA27 was isolated from the permafrost strains of Acinetobacter lwoffii. The 4135bp plasmid carries mobА and mobC genes that mediate its mobilization by conjugative plasmids. The nucleotide sequences of mobА and mobC are similar to those of mobilization genes of the modern plasmid pRAY* and its variants, which contain aadB gene, and are widespread among the pathogenic strains of Acinetobacter baumannii. Almost identical pALWED1.8 variants were detected in modern environmental Аcinetobacter strains. A highly similar plasmid was revealed in a strain of Acinetobacter parvus isolated from mouse intestine. Furthermore, we discovered six previously unidentified variants of plasmids related to pALWED1.8 and pRAY* in public databases. In contrast to most known variants of aadA which are cassette genes associated with integrons, the aadA27 variant harbored by pALWED1.8 is a non-cassette, autonomously transcribed gene. Non-cassette aadA genes with 96% sequence identity to aadA27 were detected in the chromosomes of Acinetobacter gyllenbergii and several uncharacterized strains of Аcinetobacter sp. Moreover, we revealed that the autonomo...
Source: Plasmid - Category: Biotechnology Source Type: research