The MRSA strain, called t016-ST22-MRSA-IV, resisted at least four drugs: flucloxacillin, ciprofloxacin, gentamicin, and trimethoprim. It remained susceptible to clindamycin, tetracycline, fusidic acid, co-trimoxazole, and linezolid. MRSA often plagues healthcare settings but can spread in communities, especially crowded settings with close contact.

This outbreak was the largest MRSA outbreak ever recorded in Ireland and the first known anywhere linked to bouncy castle use. Officials interviewed families and learned most children played in the castles for hours—some five, six, or more. Inside, it was crowded, and play was "rough-and-tumble," causing superficial abrasions. The weather was humid, warm, and rainy; many children were wet. These conditions were ideal for MRSA to flourish.

Of 48 infected children, 47 played in the bouncy castles. The one child who had not had very close contact with an exposed child shortly afterward. Officials concluded no other exposure was plausible; everything pointed to the castles. They decided against swabbing them: a positive surface swab wouldn't confirm the source, and MRSA might not survive on surfaces by then. Instead, health officials advised the owners to thoroughly decontaminate.