As many as 5,000 patients are going to be informed that they were exposed to the “nightmare” superbug Enterobacteriaceae, also known as CPE.
The superbug is resistant to most antibiotics and can be fatal up to 50% of the time if it gets into a person’s bloodstream.
The HSE has confirmed it will be sending letters out to the former hospital patients, alerting them that they shared a space with another patient infected with CPE.
The bacteria can live harmlessly in the gut but about one in 400 people will end up developing an infection.
The HSE advises people to "follow good practice in relation to hand hygiene to prevent spread of the bacteria and viruses".
But thankfully, the superbug might not be as terrifying as it sounds.
Speaking to the Irish Independent, Prof Martin Cormican, HSE lead on antibiotic resistance said:
"CPE infection is very uncommon, even in people who carry CPE if they are reasonably well and not in hospital. It is important to also say that for those people who get CPE infection, there are antibiotics that work to treat the infection."