New aggressive strain of Strep A spreading in UK
pharmafile | September 11, 2019 | News story | Research and Development | Strep A
A new strain of Streptococcus pyogenes called M1UK that is nine times more aggressive is spreading in the UK as the number of reported cases has risen to nearly 20,000.
Strep A bacteria live in the nose and throat and spreads when a person sneezes or coughs. The bacteria are also responsible for a surge in cases of scarlet fever and sepsis, or blood poisoning.
The number of cases reported in England and Wales has been steadily increasing from 15,000 in 2014, 17,000 in 2015 and over 19,000 in 2016.
During Spring of 2015, emm1 strains were the dominant cause of Strep throat; however, the previous year only 5% of the bacteria collected from sufferers were emm1, increasing to 19% in 2015.
2016 saw emm1 behind 33% of samples, and to investigate further scientists at Imperial College London (ICL) sequenced the genes of 135 samples collected between 2009 and 2016, finding that most of those circulating after 2015 were a ‘distinct breakaway emm1 clone’, called M1UK.
Professor Shiranee Sriskandan, Faculty of Medicine at ICL’s Department of Infectious Disease, said: “The strain that has emerged is related to this previously dominant strain called emm1. And it’s changed in a very small way in that it has acquired 27 quite small mutations.
“It seems to have got an aptitude to expand within the population in terms of causing both throat infections, and also the much rarer invasive infection.
“What’s interesting, from a science point of view, is that whatever has happened to this bacterium, it has made it more ‘fit’, or has better aptitude to cause throat infections in a population.
“One of the ways it has manifested biologically is that it can make more of one particular type of toxin called SpeA, or scarlet fever toxin.”
In response to the high rates of scarlet fever a spokeswoman from Public Health England stated: “Despite the rise in scarlet fever cases over the last five years, it remains a typically mild illness, readily treatable with antibiotics to reduce the risk of complications and spread to others.”
Nik Kiran
