To ensure no others might be breaking the rules, the Board of Registration in Pharmacy took the extraordinary step of ordering all compounding pharmacies in Massachusetts to sign affidavits swearing they are complying with state regulations prohibiting compounders from mass-producing medications.

“What they were supposed to be doing is filling specific prescriptions for specific ­patients as I think any of us would understand a pharmacy to do,’’ said Patrick, referring to New England Compounding Center, the Framingham company whose injectable steroids are at the center of the outbreak. “What they were doing instead is making big batches and selling out of state as a manufacturer would, and that is certainly outside their state ­license.

“It does seem like the agencies both at the state and the federal level may have been misled by some of the information we were given,’’ the governor told reporters.

In fact, several physicians who received shipments of the possibly contaminated steroids from New England Compounding said in interviews Wednesday that they did not provide the company with patient prescriptions to obtain the drugs, as state regulations require.

The investigation of the outbreak expanded Wednesday, as public health officials made clear they are looking deeply ­into businesses owned by the same families that own New England Compounding.

Two related companies — Ameridose of Westborough and its distributor, Alaunus Pharmaceutical — voluntarily agreed to temporarily cease all manufacturing and compounding operations immediately amid the investigation by ­Massachusetts and the US Food and Drug Administration and the Centers for Disease Control and Prevention.

New England Compounding has shut down operations and recalled all its drugs, including three lots of methylprednisolone acetate the firm shipped to providers in 23 states. The CDC has said 13,000 patients received injections of the painkiller for lower back pain. Federal officials believe those lots may have been contaminated with at least two different types of fungus, which infected patients, traveling from the injection site near the spine to the brain, causing a ­serious and rare form of meningitis.

The Globe reported Wednesday that Ameridose, a company ­licensed and regulated by federal authorities to manufacture medications on a large scale, shares the same owners as New England Compounding. Ameridose said it provides services to more than 3,000 hospitals nation­wide.

Dr. Madeleine Biondolillo, director of the state Public Health Department’s Bureau of Healthcare Safety, said that officials have not seen any evidence of “products compromised” at Ameridose but that the company stopped production to give investigators time to do a comprehensive review of its operations, including the companies’ corporate structure.

State health officials have not “requested a recall at this time” of any Ameridose products, and she stressed the agreement to cease operations is voluntary.

Biondolillo said the affidavit requirement for all compounding pharmacies was “issued purely out of an abundance of caution, consistent with our commitment to keeping the public safe.” She said she does not believe “others are operating outside the law.”

Compounding pharmacies are supposed to mix hard-to-find medications for doctors and their patients who have ­allergies, difficulty swallowing, or otherwise cannot take mass-produced drugs. They are not subject to the same manufacturing safety rules and drug pre-approval requirements as manufacturers, which are regulated by the FDA.

According to doctors at some, but not all, of the 75 clinics who received shipments of the possibly tainted steroid, New England Compounding did not require prescriptions for individual patients.