Molecular characterization of five novel plasmids from Enterococcus italicus SD1 isolated from fermented milk: An insight into understanding plasmid incompatibility

•Five novel circular plasmids pSRB2, pSRB3, pSRB4, pSRB5 and pSRB7 have been identified, coexisting in Enterococcus italicus SD1, isolated from fermented milk.•The plasmids pSRB2, pSRB3 and pSRB5 replicate via theta mode of replication while pSRB4 and pSRB7 were rolling-circle plasmids.•The scale of relatedness of the DNA binding domain of replication proteins and the iteron sequences, along with the mechanism of replication, determines the compatibility of theta replicating plasmids.•Rolling circle plasmids with variable replication protein binding sites in the origin of replication and dissimilarities in replication protein allow plasmids to coexist.