Scientists in Singapore crack Group B Streptococcus (GBS) genetic code

A raw fish dish from a coffee shop.
A raw fish dish from a coffee shop.PHOTO: THE NEW PAPER FILE

This could lead to quicker diagnosis, vaccine for bacteria strain linked to eating raw fish

Scientists here have decoded the genetic blueprint of the strain of Group B Streptococcus (GBS) bacteria linked to people who fell sick after eating raw fish here.

This could take doctors and researchers closer to quicker diagnosis and vaccine development.

The Agency for Science, Technology and Research's (A*Star) Genome Institute of Singapore (GIS), Tan Tock Seng Hospital and the Singapore Infectious Disease Initiative were involved in the project.

In July, researchers had taken a blood sample from a patient with GBS and used next-generation sequencing to analyse it.

They found that this strain looked different from earlier strains of GBS.

Dr Swaine Chen, a senior research scientist in the GIS Infectious Disease group who led the study, said the bacterium could carry mutations, or changes from earlier versions, that make it more likely to cause disease.

However, in order to discover how and why the bacterium changed, and the mechanisms by which it infects the body, would require further study.

Professor Dale Fisher, head and senior consultant from the National University Hospital's Division of Infectious Diseases, says that he is hopeful that, with the genetic code, more data on the GBS could be collected.

"Perhaps the most important information we need is where GBS comes from, for instance, which foods. If we could prevent the infection in the first place, that is always best," he said.

Prof Fisher added that if a test to diagnose patients more rapidly could be formulated, it would allow doctors to choose a specific and targeted antibiotic from the start, instead of waiting for the results of traditional cultures, which usually take about 48 hours. He said: "The rapid test would have to be very sensitive and specific in order for patients to reap the most benefits."

The Health Ministry received reports of a total of 238 cases from public hospitals from Jan 1 to June 30, up from an average of 150 cases a year for the past four years.

However, since licensed shops and foodstalls were advised to stop selling raw fish dishes using the Asian Bighead Carp (Song fish) and Toman Snakehead fish - the two types of fish linked to GBS - on July 24, there has been a fall in the number of cases.

A weekly average of three cases was reported in the past three weeks, down from an average of 20 cases since the start of the year.

A version of this article appeared in the print edition of The Straits Times on September 17, 2015, with the headline 'Scientists crack GBS genetic code'. Print Edition | Subscribe