Escherichia coli K-12 Genome sequencing and assembly

The nucleotide sequences of R16a and IP40a (R40a) (Chabbert et al. 1972), two "ancient" IncA/C plasmids isolated in the late 60''s from urine and abscess samples in Pasteur Institute, and their spontaneous rearrangement products have been determined in the framework of the ONT MinION Access Programme (MAP). Both plasmids proved to belong to A/C2 Type 1 group and carry aphA1b, blaTEM-1 and sul2 genes conferring resistance to kanamycin, ampicillin and sulphonamide, respectively. Majority of the rearrangements detected in R16a, IP40a and R55 seem to be associated with transposons. The presence of relatively few and archaic antibiotic resistance genes and the complete GIsul2 island, which is absent from all the known IncA/C plasmids, suggest that these plasmids represent an ancient form in Type 1 lineage.