"All patients who may have received these medications need to be tracked down immediately," said Benjamin Park of the Centers for Disease Control and Prevention.
"It is possible that if patients with infection are identified soon and put on appropriate antifungal therapy, lives may be saved," he said in a statement.
The CDC listed three facilities in the Philadelphia region, all in South Jersey, that received recalled lots: Premier Orthopedics Surgical Associates L.L.C. in Vineland, and South Jersey Healthcare in Vineland and Elmer.
Officials said Friday they have found fungal infections in nine sick patients nationally. They weren't able to identify what type of fungus in every case, but did distinguish at least two types - Aspergillus and Exserohilum.
In all, 47 people have contracted fungal meningitis, the CDC said. Three people have died in Tennessee and one in Virginia and Maryland.
About 17,700 single-dose vials of the steroid were covered in the recall by New England Compounding Center in Framingham, Mass.
It's not clear how many of those were sent to clinics, how many were used, or even whether everyone who got one will get sick. It can take as long as a month for symptoms to appear.
Doctors who do these injections say they are extremely safe when done correctly with sterile drugs. And many doctors stick to medications approved by the Food and Drug Administration instead of relying on generally less-regulated "compounding pharmacies" like the one implicated in the outbreak.
Some doctors who have relied on such places are rethinking the practice.
Michael Drass of Allegheny Pain Management, a clinic in Altoona, Pa., said he has pulled all drugs that came from the New England Compounding Center off his shelves - as the government has urged physicians to do - and is reevaluating whether to rely on compounding pharmacies for the medicines he uses to treat patients.
"I've been doing this for 15 years now, and I've done 50,000 injections over that course of time, and I've never seen or heard anything like this. It's a real eye-opener for us in the medical practitioner community," Drass said.
He said he has used the New England pharmacy and others like it because they sometimes have medications he can't get elsewhere, sometimes because of shortages. Cost can also be a factor.
The injections are a common treatment for sciatica, which is pain from a slipped or ruptured disk that often radiates down the legs, and for spinal stenosis, an age-related narrowing of the spine sometimes caused by arthritis. It results in pain or weakness, usually in the neck and lower back.