Researchers work on bug that hit Lana

By MARTIN JOHNSTON

Auckland scientists are working on a potential vaccine against the life-threatening illness that attacked television personality Lana Coc-Kroft.

Coc-Kroft spent nine days in a coma and weeks in hospital battling a group A streptococcal infection thought to have arisen from a coral cut.

After the injury while filming in Fiji for Celebrity Treasure Island, Coc-Kroft was flown back to Auckland in April after becoming delirious. She suffered toxic shock, a heart murmur, nerve damage and abscesses in joints.

"She is lucky that she survived," Auckland University senior research fellow Dr Thomas Proft said yesterday.

Streptococcal toxic shock was fatal in 50 to 70 per cent of cases, said Dr Proft, who has won a prize from the Queenstown Molecular Biology Meeting, which starts next week, for work on toxins produced by group A streptococcus and staphylococcus aureus bacteria.

Strains of both bacteria have developed into "superbugs" that are resistant to many antibiotics.

Both bugs are harmless to most people, but are linked to a range of ills.

In serious cases they can both lead to the rare skin-eating disease necrotising fasciitis and toxic shock.

Building on US researchers' sequencing of a streptococcal genome in the late-1990s, Dr Proft and colleagues discovered three new "super-antigens".

"These are extremely potent toxins that send our immune system into overdrive. Less than one picogram - one million-millionth of a gram - per millilitre of body fluid can cause fatal shock," he said.

Samples from hospital patients suggested that a lack of protective antibodies against the streptococcal toxins was a risk factor for toxic shock and other invasive streptococcal diseases.

The researchers changed several of the 250 or so amino acids on each of the super-antigens. The aims are to prevent the toxins from triggering the fatal response of the immune system and to induce it instead to produce protective antibodies.

Dr Proft had no idea how long it might take to develop a safe and effective vaccine.

The BBC in August quoted US scientists saying that preliminary trials on humans had shown promising results for a vaccine against the streptococcal A bacterium.