NEW YORK -- A deadly meningitis outbreak rose to 47 cases in seven states Friday, as clinics scrambled to notify patients across the country that the shots they got for back pain may have been contaminated with a fungus.

The tally of deaths from the rare fungal meningitis remained at five. But a seventh state, Michigan, was added to the list with four cases, the Centers for Disease Control and Prevention said Friday.

Tennessee's cases now total 29; Virginia, six; Indiana, 3; two each in Maryland and Florida and one in North Carolina.

Looking for a source of the outbreak, investigators have focused on a steroid custom-made by a specialty pharmacy, New England Compounding Center in Framingham, Mass. Health inspectors found fungus in at least one sealed vial of the steroid at the company's facility this week.

The pharmacy recalled 17,676 single-dose vials of the steroid, methylprednisolone acetate. Shipments went to clinics in 23 states.

As a precaution, the Food and Drug Administration urged physicians not to use any of the company's products, and on Friday released a list of them.

The first known case in the meningitis outbreak was diagnosed about two weeks ago in Tennessee. Three of the five deaths are in Tennessee; the others in Virginia and Maryland.

Meningitis is an inflammation of the lining of the brain and spinal cord. Symptoms include severe headache, nausea, dizziness and fever.

The type of fungal meningitis involved is not contagious like the more common forms. It is caused by a fungus that's widespread but very rarely causes illness. It is treated with high-dose antifungal medications, usually given intravenously in a hospital.