I don't have carpet but also have play mats and I wash them 3 times a day, add a few drops of tea tree oil to your wash water/soap and it's a natural disinfectant, or 1/2 cup of peroxide to your water.
I also make all kids wipe there feet with wipes before entering the house they get washed by me if too young.
I supose I'm relaxed as we play in the yard in our bare feet! After all it's summer!