Disease control workers carried out an environmental investigation at a “sex-on-site” venue in Dublin following an outbreak of antibiotic-resistant dysentery among men who have sex with men (MSM).

The investigation was ordered after it was found that four people who contracted shigella, or bacillary dysentery, reported having had sexual activity in Dublin city and two said they had visited the venue, according to the HSE’s Health Protection Surveillance Centre.

This is the second outbreak of shigella among MSM within a year. Thirty cases were identified last year but the latest outbreak, though smaller, has caused concern because the infection is multi-drug resistant and more severe.

The outbreak was first suspected last December and an infection control team was convened. All four cases were MSM linked to Dublin, who ranged in age from late 20s to early 50s.Three people who were HIV positive required hospital admission.

The investigation of the venue did not identify an environmental source but management was given recommendations for reducing the risk of transmitting the infection at the venue.

The HPSC says the outbreak demonstrates the growing impact of antibiotic resistance. In New York, where similar outbreaks have occurred, researchers say HIV-positive MSM may be at increased risk of such infections due to “transmission-facilitating” behaviour or because of increased exposure to strong antibiotics used to treat sexually transmitted infections.

Shigellosis is an infectious disease caused by the shigella bacterium. People who are infected develop diarrhoea, fever and stomach cramps a day or two after exposure. The disease is common in parts of the world where lower sanitary conditions prevail, and is frequently the cause of “traveller’s diarrhoea” in the developing world.

The disease is highly contagious and transmission is usually caused by hand or mouth contact with contaminated food. It can also be transmitted by exposure to faeces through sexual contact.