Disease microbe grows more dangerous

THE MICROBE causing the deadly outbreak of disease in Gloucestershire has become more lethal in recent years, scientists said yesterday.

Streptococcus bacteria, which can live harmlessly on the skin and usually cause little more than a sore throat, appear to have gained a potent virulence that is making them as lethal as they were 50 years ago, before the advent of antibiotics.

Michael Barnham, a consultant medical microbiologist at Harrogate General hospital and an expert on streptococcus bacteria, said there had been a marked increase in dangerous strains of the bacterium in Western countries in the past decade.

An outbreak of potentially lethal forms of streptococcus in patients with no obvious connection in one area is extremely unusual, he said. 'Things do sometimes cluster together by chance. Invasive strains of the bacteria will circulate within communities from time to time. We don't know why some people are susceptible.'

Streptococcus bacteria can cause scarlet fever, rheumatic fever, childbirth fever, septicaemia and 'necrotising fasciitis', when the microbe invades deep into several layers of tissues, producing deadly toxins and killing cells as it grows.

Professor Bill Noble, a microbiologist at St Thomas's Hospital in London, said: 'There is enough evidence that streps possess the armoury to produce damage in a number of different ways. My guess is that the strain in Gloucestershire will not turn out to be new. What may be new is having a number of cases all very close together.'

Toxins produced by bacteria can differ in their potency as well as their quantity. Some toxins are able to melt fatty tissue under the skin, others can punch holes in proteins, causing cells to burst like water-filled ballons. One suggestion is that the strains of streptococcus in Gloucestershire have been triggered into producing greater quantities of the more deadly forms of toxins, which rapidly allow disease to take hold.