AUSTRALIA—The move comes after two transplant patients contracted severe pneumonia as a result of the infection, one of whom died.

Professor Graeme Russ from the Renal Transplant Service says the number of cases in South Australia is higher than usual and follows an outbreak in the eastern states.

He says about 800 patients will be offered antibiotics and says the infection is caused by an organism known as pneumocystis.

"Pneumocystis is an organism that can cause quite severe pneumonia in people whose immune systems have been suppressed, so people for example who have received organ transplants and who are on immunosuppressive drugs are more prone to develop this pneumonia," he said. "The organism is present in a number of other people but if you've got a normal immune system you don't get sick from it."

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