Coliform bacteria, which include salmonella and E. coli, are a sign of fecal contamination. Staphylococcus aureus, aka staph, can hang out in your bathroom, too. The hotspots: toothbrush holders, toilet handles and seats, faucets, and doorknobs.
What to do:
Zero in on these areas when you clean. Use a household cleaner to remove germs and dirt, and follow up with a disinfectant to kill germs.