Common DNA stretch in E.coli plasmid and genomic DNA

[geniusgene]

Is there any strech of sequence that is common in E.coli genomic as well as plasmid DNA? I am trying to find a target for PCR using universal primer against such a sequence so that it will help me in detecting the presence of genomic as well as plasmid DNA in my sample.

[mattbimbo]

don't you want to differentiate between coli genomic and plasmid DNA?

after all you won't have plasmid DNA without genomic DNA.

[geniusgene]

No.. I just want to detect E.coli DNA contamination in my sample

[jeskill]

what about using primers for ribosomal DNA?

[geniusgene]

Thanks for your reply. Yes we target 16S rRNA sequence for E.coli genomic DNA whereas antibiotic resistance gene in plamid. But that required two set of reaction in quantitative PCR. I was looking for a universal sequence that would help me to perform the test in just one reaction.