The consultant who helped save a Swindon grandmother from an illness that has affected only 200 people in the world has said it was the worst case of kidney infection he has ever seen.

Housewife Janet Connor, 56, is believed to be the only person in Swindon, and possibly England, to have emphysematous pyelonephritis a gas forming ecoli in the kidneys.

And it is so rare that Janet's consultant at the Great Western Hospital, Rupert Beck, said he had never come across it before in his 15 years in medicine.

Mr Beck, 41, said: "In the six years I have been in Swindon I haven't seen a kidney infection like Janet's. It was extremely severe.

"When she was first brought in we did fear the worst. She collapsed in casualty and a subsequent CT scan showed severe infection all around her kidney."

Janet was taken to the GWH last month after she became delirious and failed to recognise her family.

Doctors determined that a kidney stone had burst causing the organ to rupture, which lead to the severe infection.

"It had produced a form of gangrene in and around the kidney and she also had a couple of pints of puss around the lung which needed to be drained off," Mr Beck said.

"The surrounding tissues had become infected which meant the muscle down to her hip had been destroyed."

Mrs Connor, of Haven Close, Coleview, had the kidney removed, and has spent the last three weeks in intensive care.

Mr Beck, who moved to Swindon's former Princess Margaret Hospital from Guy's Hospital, London, in 1997, added: "None of the original infection remains now, although there is a little infection in her bowel which is secondary to the antibiotics.

"A lot of her recovery depended on the care she received in intensive care. But she is still extremely weak."

Mrs Connor's daughter Karen Hughes, 36, said: "It's really a miracle that she's alive. But mum's a fighter. She's been through an awful lot in the past three weeks but she's still with us and that is truly amazing.

"We aren't sure if she will fully recover. Her immune system is still very low and she needs to build herself back up."

Shop manager Mrs Hughes, of Osborne Street, Gorse Hill, added: "Mum was very shocked when we told her what she has been through. She can't remember anything about it. But she says she can't wait to get home and spend time with her six grandchildren."

Mrs Connor's other children are Tracey Baxter, 36, and Mark Connor, 32. Her husband Colin, 59, a builder, said: "We were all so worried because no one seemed to know what was wrong with her.

"She has now been moved into a separate ward because of the risk of infection."