Dr. Al DeMaria, Mass. State Epidemiologist, answers a reporter's question regarding a meningitis outbreak linked to medicine from a Massachusetts specialty pharmacy during a news conference in Boston, Thursday, Oct. 4, 2012. (Charles Krupa/AP)

More than 17,000 vials of an injectable steroid that has been linked to 35 cases of meningitis, five of them fatal, were sent to doctors’ offices and clinics in 23 states over the summer, health officials said Thursday.

How many of the vials remain unused is not known. All have been recalled, and the Massachusetts pharmacy that made them has stopped shipping all products, the officials said.

Fungus in some of the vials appears to have caused a rare brain infection that requires months of intravenous antibiotics to cure. Federal health authorities have asked physicians to contact every patient who might have received the drug from three contaminated lots.

“Despite the current recall, we expect to see additional cases,” Benjamin Park, a physician at the Centers for Disease Control and Prevention, told reporters. “It is possible that if patients are identified soon and started on antifungal therapy, some of the unfortunate consequences may be averted.”

The medicine, methylprednisolone acetate, is injected around the spinal cord in the lower back to relieve pain caused by ruptured disks or spinal stenosis. It gains access to the brain through a ­waterlike substance called cerebrospinal fluid.

Symptoms sometimes take one to four weeks to appear. They include fever, headache, nausea and strokelike weakness.

The drug was made by New England Compounding Center of Framingham, Mass., west of Boston. Little could be learned about the company Thursday. Its Web site was down; a call was not returned.

“Compounding pharmacies” are essentially boutique drug companies. They custom-make medicines for individual patients. The products are usually drug formulations not available through conventional pharmaceutical manufacturers in the dose or quantity needed.

Of the country’s 56,000 community pharmacies, 7,500 are compounding pharmacies, and 3,000 make sterile products, said David G. Miller, head of the International Academy of Compounding Pharmacists, in Houston.

Miller said that national dis­tribution of a common drug in large quantities is distinctly uncommon.

“This does not look like traditional pharmacy compounding at all,” he said.

Six states, including Maryland and Virginia, have reported ­cases. Tennessee, where the first case was identified Sept. 28, has 25 cases and has reported three deaths.

Massachusetts officials said the three suspect lots of methylprednisolone contained 17,676 single-use vials. They were shipped from July through September.

How many products New England Compounding Center makes was not clear, but the officials said it was at least a dozen. Food and Drug Administration officials advised physicians to use no products made by the company.

Four cases of meningitis believe to be linked to the medicine have been reported in Virginia, the most recent on Wednesday. The cases were in the state’s southwestern region, near the border with Tennessee, state health officials said. One patient has died, and three patients remain hospitalized.

An estimated 500 people received the steroid injection at two outpatient facilities, said David Trump, Virginia’s state epidemiologist. Staff members at those facilities have been contacting patients who received the steroid since July 1, he said.

“The concern really is that several hundred people may need evaluation,” he said.

Two cases have been identified in Maryland, one of whom has died. State health officials believe that hundreds of people might have received the injections at seven facilities, most of them in Baltimore and surrounding suburbs. The state has contacted the facilities to make sure they remove the product and notify patients potentially exposed from July 30 to Sept. 28, officials said.

Precise identification of the fungus is in the works, but in one case it was found to be Aspergillus, a type found on decaying vegetation, hay and stored grain.

Ilisa Bernstein, of the office of compliance at the Food and Drug Administration, said that inspectors who visited the Massachusetts company last week found a sealed vial whose contents contained microscopic amounts of fungus.

Madeleine Biondolillo, director of the Bureau of Health Care Safety and Quality at the Massachusetts Department of Public Health, said the state’s Board of Registration in Pharmacy had received complaints “related to sterile compounding procedures” at the company in 2002 and 2003. Inspections and negotiations led to a consent decree, the details of which were not immediately available.

Another complaint last year about sterility led to an inspection but no violations were found. A fourth complaint, about the potency, not sterility, of a medicine used in eye surgery, is being investigated, she said.

The health-care centers in Maryland that received products from the implicated lots are:

-- Berlin Interventional Pain Management, Berlin, Md.

--Box Hill surgery Center, Abingdon, Md.

--Greenspring Surgery Center, Baltimore, Md.

--Harford County Ambulatory Surgery Center, Edgewood, Md.

--Maryland Pain Specialists, Towson, Md.

--SurgCenter of Bel Air, Bel Air, Md.

--Zion Ambulatory Center, Baltimore, Md.