Science Headlines – Hospital Bugs

Science Headlines – Hospital Bugs

An information service for media in New Zealand

For more information you may contact any of the following scientists directly, or email headlinescience@rsnz.org or call 04 4705758.
20 October 2006

A recent streptococcal A outbreak killed three elderly patients in Christchurch; scientists talk about the bacterium, the toxic proteins it produces, and general infection risk in hospitals.
1. Dr Diana Martin, a microbiologist at the ESR Kenepuru Science Centre
Phone (work): 04 914 0778
Mobile: 021 822 244
Email: Diana.martin@esr.cri.nz

“In any one year we’d have 200-300 streptococcal A cases referred to us for analysis. The recent cases highlight an increase of a particular type of strep A occurring in New Zealand this year, and this particular M type can cause severe disease. In 2004 we had 17 M type 1 cases and in 2005 we had 18. This year, so far, we’ve had 38. So if the recent cases had been in different hospitals they probably wouldn’t have been noticed – it’s come to our attention because it’s a cluster.”

2. Dr Thomas Proft, a molecular microbiologist at the School of Medical and Health Sciences at The University of Auckland
Phone (work): (09) 3737599, ext. 86213
Email: t.proft@auckland.ac.nz

“These highly invasive group A streptococcal (GAS) infections have been increasingly recognised and reported since the 1980s. However, the real problem is often not the bacterium itself, but small toxic proteins - superantigens - it produces. Just one picogram of superantigens per millilitre of body fluid can stimulate part of our immune system enough to cause fever, shock and eventually death.”

“But these superantigens are difficult to find in the human body because they only appear briefly. We’re actually the only team in the world to have found a bioactive superantigen in a human sample – the very potent superantigen streptococcal mitogenic exotoxin Z (SMEZ).

“Most people have protective antibodies to several superantigens, but not to all of them. When Lana Coc-Kroft got strep A from a tiny coral cut she first thought she had the flu. By the time she went into hospital she was in shock and the superantigens had disappeared from her body. She also lacked protective antibodies to the superantigen SMEZ. But two weeks later her reults showed seroconversion towards SMEZ - the antibodies had appeared indicating an immune response against this superantigen.”
3. Dr Helen Heffernan, a microbiologist at the ESR Kenepuru Science Centre
Phone (work): 04 914 0781

Email: helen.heffernan@esr.cri.nz
“One of the common issues with bacteria that cause hospital-acquired infections is that they are often antibiotic-resistant strains – bacteria transmitted in hospitals tend to be more resistant than those out in the community. But the group A streptococcus is a bit of an enigma. It can be an extremely virulent bacterium, but it’s remained exquisitely sensitive to one of the first antibiotics we ever had – penicillin. In contrast, within 10 years of penicillin’s introduction, 80% of staphylococci had become resistant. But the group A streptococcus never has.”

Science Headlines is a service managed by the Royal Society of New Zealand and funded by the Ministry of Research, Science and Technology.

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