Do bacteria have S-S linking mechanism?

[MrMistery]

OK, so if you want to make fully functional humuline you need it to have the right 3d structure right? this means you need the bacteria to create the propper disulfide bridges, right?
my question is: do you insert the gene that codes for the disulfidisomerase enzyme in the bacteria along with the insulin gene, or do bacteria have them on their own? and another thing: if they do have them, how come these enzymes do not interfere with the normal proteins that do not need disulfid bridges, although they are possible to create(disulfidisomerases, from what i know, are very unspecific in the formation of bonds, and go by a trial-and-error mechanism)because bacteria don't have an ER to trap the enzyme there like eukaryotes...

I've asked this question to many people and never got a complete and trustworthy answer