How to access JSON field with dot?

I have this JSON

[{"usr_pres.name":"xxx","emp":"001"}]which returns an ajax function.

I've always accessed each element like this:

success: function (data) {
            objJsonPT = JSON.parse(data);
            console.log(objJsonPT['0'].emp);

If I access the value of emp, it returns it fine but if I access the value of usr_pres.name it gives me an error, it says that name is not defined. I think it has to do with the"."

However, when I do a console.log(data)yes, I see the data well as I show it.

[{"usr_pres.name":"xxx","emp":"001"}]

What I would like would be to be able to access the value usr_pres.namethat would be: "xxx"

Thank you