Five elderly residents of a Christchurch rest home have died after an outbreak of strep A.
Six female residents, aged between 86 to 97 years, were rushed to Christchurch Hospital on May 30 after contracting the infection.
Five of them have subsequently died, with one remaining in hospital in a stable but serious condition.
The rest home, owned by Ultimate Care Group, has swabbed and tested the other 70 residents, but none have tested positive.
But as a preventative measure, all other residents have been give a course of antibiotics, said Ultimate Care Group general manager operations Ron Spraggon.
"Our focus has been on preventing the spread of it and at this stage there has been no other cases, so it has been contained," he said.
"The families have been very positive towards the facility and particularly the staff, knowing the circumstances they have been operating under."
It's still not known how the infection made its way into the Addington rest home, and Mr Spraggon said his team are investigating its origins.
Strep A is spread by droplet, or by direct contact with an infected wound.
Mary Gordon, Canterbury DHB acting chief executive and Executive Director of Nursing, says the DHB's response has been focused on halting transmission.
"Patients and staff at the rest home and staff at Christchurch Hospital as well as relatives of the patients have been contact traced, had throat swabs and have been provided with antibiotics as a preventative measure," she said.
"The response to this outbreak has been a real team effort with staff from the rest home, public health, infection control, Christchurch Hospital, and our labs working swiftly to contain this outbreak."
DHB staff have passed on their condolences to the families of the individuals who have died.
"All those caring for the elderly in the health sector work as hard as possible to keep those in their care well and to prevent instances like this from occurring."
There are no new cases to date but results from throat swabs show three hospital staff members have tested positive for strep A, two of the three staff had skin swabs which showed the outbreak strain.
Strep A is more commonly associated with sore throats, rheumatic fever and skin infections.
"Most infections are relatively mild illnesses such as strep throat or impetigo but on rare occasions, such as when the infection is in a frail elderly person, an infant or someone with a weak immune system, these bacteria can cause severe and even life-threatening complications," Ms Gordon said.