A number of chemotherapy drugs have been recalled, as a precautionary measure, following fears they may have been contaminated during manufacturing.
Dublin-based pharmacy Fannin Compounding issued a safety alert after a machine it uses to manufacture the medicine was found to have been contaminated.
The bacteria, which can cause potentially life-threatening gastro-intestinal infections, was found in batches of drugs during routine testing.
Fannin Compounding has been at the centre of precautionary product recalls three times in the past six months.
In a statement, the HSE said any patients who had received the medicine being recalled had been contacted by their hospitals and offered appointments with their clinical teams.
It said there was no indication, to date, that any drugs given to patients had been contaminated.
About two hundred patients were affected by the recall.
In a separate statement, the Health Products Regulatory Authority, which is overseeing the recall, said a contaminant had been found in a "single unit of a test product".
It said that as a precaution, all units of the same batch had been recalled. The medicine was manufactured between 29 September and 12 October.
The HPRA stressed that the test product itself was not a medicine and had not been given to patients.
It said the equipment used in the manufacture of the drugs had been taken out of use while investigations at the plant continued.
Fannin Compounding has said it has been working closely with the HSE and HPRA in relation to the recall.
In a statement, the company said "investigations are ongoing as to how this issue arose and immediate corrective actions have been implemented, including taking the isolator in question out of use."
The statement added the company regrets any upset to patients in relation to the recall.
John Lynch of the Health Products Regulatory Authority referred to the drugs in question as a range of oncology or anti-cancer drugs, known as patient specific packs.
Speaking on RTÉ's Drivetime, he said there are, possibly, somewhere over 100 patients who have received the potentially implicated products, adding the patients are being treated in 13 public hospitals and six private hospitals.
Mr Lynch said, to his knowledge, all patients have been informed and patients will know of the contaminated product if they experience an "elevated temperature".
He denied there was a media blackout, describing the recall as "precautionary" to stop any further use of the product.
