Strain of bacteria linked to infections from raw fish found

Scientists from A*STAR’s GIS, together with TTSH and the Singapore Infectious Diseases Initiative have sequenced the strain of Group B Streptococcus (GBS) responsible for the increase in severe infections observed in Singapore this year, which could lead to tests for detection of the strain.
Channel NewsAsia 17 Sep 15;

SINGAPORE: Scientists from A*STAR’s Genome Institute of Singapore (GIS), together with Tan Tock Seng Hospital and the Singapore Infectious Diseases Initiative have sequenced the strain of Group B Streptococcus (GBS) responsible for the increase in severe infections observed in Singapore this year.

With the sequence, the team of scientists are now working to develop new tests for the detection of this bacteria strain.

In a media release, GIS on Thursday (Sep 17) said it has managed to isolate the strain of GBS - known as Streptococcus agalactiae - that caused meningitis in a local patient. It noted that the recent outbreak of GBS was unusual, as it is associated with the consumption of raw Song (Asian bighead carp) and Toman (snakehead fish).

Dr Swaine Chen, Senior Research Scientist in the GIS Infectious Diseases Group and Assistant Professor in the Department of Medicine at National University of Singapore Yong Loo Lin School of Medicine who led the project said, “Sequencing is a key first step in modern infectious disease outbreak investigation. Having the sequence will help with ongoing studies to understand how and why this strain can cause serious disease. We are making this data publicly available immediately to accelerate progress as much as possible.”

Dr Chen added: "By having this DNA sequence, now when we see another sick patient, we can be very precise in knowing this is the same strain and part of the same outbreak. If it is coming from the food, we can be very sure that this same strain that caused the infection in the patient is actually the one that's present in the food as well. So this helps overall, in terms of us being able to track what's happening - if it is contamination of food (that caused a patient's illness) or if the outbreak is still ongoing."

DEVELOPING A SIMPLER TEST

Prof Timothy Barkham, Senior Consultant in Laboratory Medicine, TTSH and Adjunct Associate Professor, Department of Microbiology, National University of Singapore Yong Loo Lin School of Medicine said the initial genome sequence will assist in the development of a simpler test that would enable medical professionals to detect the bacteria faster and more cost effectively.

“If a simpler test can be developed, it will contribute to testing patients, food products and surveillance. While we are gratified to see the reduction in cases recently, the GIS sequence can now be studied to look for clues as to why this strain causes serious disease and where it may have come from," he said.

Most strains of GBS bacteria, found in the gut and urinary tract of about 15 to 30 per cent of adult humans, pose little danger to healthy people, GIS said.

Earlier in 2015, MOH observed an increase of patients infected by the GBS bacteria – an average of 20 cases per week since the beginning of the year. Before the outbreak, MOH saw about three cases of GBS infections per week.

- CNA/dl