The World Health Organization is warning against the spread of a strain of gonorrhoea.
At least three people worldwide are infected with the untreatable superbug strain.
The disease is spreading thorough unprotected sex, WHO said.
'Gonorrhea is a very smart bug,' said Teodora Wi, a human reproduction specialist.
'Every time you introduce a new type of antibiotic to treat it, this bug develops resistance to it.'
No known antibiotic is effective on the particular strain of the STI.
The three cases were found in Japan, France and Spain.
The number of sexually transmitted infections grew by 10 per cent in 2016 in Ireland, according to the HSE’s Health Protection Surveillance Centre, and gonorrhoea saw one one the biggest spikes.