It was the first time the CDC has given an estimate of the number of patients potentially affected, having previously said only that it could be in the thousands.

So far, 105 cases of the rare form of meningitis have been confirmed in nine states. In worst-hit Tennessee another person has died, bringing the national death toll to eight, the CDC and Tennessee state authorities said on Monday.

The Saint Thomas Outpatient Neurosurgery Center in Nashville received about 2,000 of the 17,676 vials of potentially tainted steroid, more than any other facility in the country, said Tennessee Health Commissioner Dr John Dreyzehner.

Dealing with patients who received the injections has been an "horrific experience" in many ways, said Dr Robert Latham, director of the Infectious Diseases Program at Saint Thomas.

"We've seen upwards of 40 to 50 patients a day since last Monday through the emergency room that have had to be extensively evaluated," he said.

The widening outbreak has alarmed health officials and focused attention on regulation of pharmaceutical compounding companies such as the one that produced the drugs - the New England Compounding Center Inc in Framingham, Massachusetts.

"We anticipate finding some additional infections," said CDC spokesman Curtis Allen. He could not say if all 13,000 people had been contacted, but said efforts had been made to find them in the last few days and the recall should limit the outbreak.

In Ohio, health officials said they were mobilizing community resources, including sheriff's offices, to check on patients who have received the injections.

"If that means knocking on doors, then that's what they will do," Beth Bickford, executive director at the Association of Ohio Health Commissioners, said in a statement.

The steroid is used as a painkiller, usually for the back. Meningitis is an infection of the membranes covering the brain and spinal cord. Patients can begin to show symptoms up to a month after injection.

The potentially tainted drugs were produced as early as May 21 and shipped to 76 facilities in 23 states through September, the CDC and Massachusetts Health Department said.

The company has suspended its operations while an investigation proceeds. It initially recalled the three lots of the drug, and expanded its recall on Saturday to all products compounded and distributed at its Framingham facility.

The address listed in state records for the company is a rundown two-storey complex in a scruffy area of Framingham, Massachusetts, Reuters journalists who visited the site said. The journalists who tried to visit the building were ordered off the property by a security officer.

A compounding pharmacy takes medications from pharmaceutical manufacturers and makes them into specific dosages and strengths for use by doctors.

Complaints against the company in 2002 and 2003 about the processing of medication resulted in an agreement with government agencies in 2006 to correct deficiencies, the Massachusetts Health Department said.

LIMITED FDA AUTHORITY

In 2011, there was another inspection of the facility and no problems were found. In March 2012, a complaint was made about the potency of a product used in eye surgery procedures. That investigation is continuing, state officials said.

The U.S. Food and Drug administration has limited authority over the operations of compounding pharmacies, which are regulated primarily by state boards that oversee the practices, licensing and certification of pharmacies and pharmacists.

Compounded products do not have to win FDA approval before they are sold, and the agency has no jurisdiction over how the products are manufactured or labeled for use. The FDA probes cases of adulterated drugs in cooperation with state regulators.

The FDA has tried to exert greater authority over compounded drug products. But those efforts led to federal court challenges that resulted in conflicting court rulings.

Massachusetts Democratic Congressman Edward Markey said compounders fall into a federal regulatory "black hole."

"If compounding is done on a large scale and is not done properly, compounders can expose large numbers of patients to health risks associated with unsafe or ineffective medications," he said in a letter to the FDA on Monday.

The nine states where fungal meningitis cases have been reported are Florida, Indiana, Maryland, Michigan, Minnesota, North Carolina, Ohio, Tennessee and Virginia.

Tennessee accounted for most of the cases, with 35 and four deaths. Virginia has 23 cases and one death, Michigan 21 cases and two deaths and one person has died in Maryland. (Link to graphic here)

Fungal meningitis symptoms include fever, headache, nausea and neurological problems consistent with deep brain stroke.

The steroid was sent to California, Connecticut, Florida, Georgia, Idaho, Illinois, Indiana, Maryland, Michigan, Minnesota, North Carolina, New Hampshire, New Jersey, Nevada, New York, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Virginia and West Virginia, the CDC said.

A list of facilities that received vials from the infected lots can be found via the website www.cdc.gov .

(Additional reporting by Ros Krasny, Mary Wisniewski and Greg McCune; Editing by David Brunnstrom)

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