Saturday, 29 August 2015

No link between GBS infection and eating sashimi, says MOH

It responds to claims of a bacterial outbreak from consuming contaminated raw fish
By Amelia Teng, The Straits Times, 28 Aug 2015

The Ministry of Health (MOH) has not found any links between the Group B Streptococcus (GBS) infection and the consumption of Japanese raw meat or fish dish sashimi.

In a Facebook post, it responded to messages circulating by SMS and WhatsApp from an unknown source that claimed a person had died recently from a bacterial infection after eating sashimi over the National Day weekend, and that a professor had been critically ill after consuming salmon sashimi two months ago.

The MOH said its investigation found only an association between the GBS infection and the consumption of "yusheng-style" raw fish sold at food stalls.

It had previously found traces of GBS in some raw fish samples, although it said more cases would have to be studied before a definite conclusion can be made.

In its post on Wednesday, the MOH highlighted that there has been a "significant downtrend" in the number of GBS cases since the middle of last month, when licensed foodshop and food stall holders were advised to stop selling raw fish dishes using Song fish, also known as Asian Bighead Carp, and Toman fish, also known as Snakehead fish.

A weekly average of three cases has been reported in the past three weeks, down from an average of 20 at the start of the year.

The WhatsApp messages warning of a bacterial outbreak from eating contaminated raw fish began circulating last month.

GBS is a common bacterium found in the gut and urinary tract of 15 to 30 per cent of adults, but it does not cause disease in healthy individuals. However, it may occasionally cause infections of the bloodstream, skin and soft tissue, joints, lungs and brain.

Those with chronic or multiple conditions are at higher risk of getting GBS infections.

MOH advised vulnerable groups, especially young children, pregnant women, elderly persons, or people with chronic illnesses such as diabetes, to continue to exercise caution by avoiding raw ready-to-eat food.

Madam Amy Quek, 57, a sales manager, said she received the latest message from her sister-in-law on Wednesday. "The messages seem to indicate that the rumours about such poisoning are true... so I've asked my family to lay off raw fish and meat for now."

Media researcher Michael Netzley said it is common for such messages to "spread like wildfire" because of their emotionally charged content and the fear that the rumours may be true.

"Even though there's no conclusive evidence (to link sashimi consumption to the infection), most people think - better safe than sorry, given that raw fish is such a common food item here," said Dr Netzley, the academic director of executive development at Singapore Management University.

MOH has been alerted to another Whatsapp/SMS message being circulated today about Group B Streptococcus (GBS) infection...
Posted by Ministry of Health on Wednesday, August 26, 2015

* 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 2015

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.”

How will isolating the particular GBS bacteria strain linked to infections after eating yusheng help? Dr Swaine Chen from A*STAR explains.
Posted by Channel NewsAsia Singapore on Thursday, September 17, 2015

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."


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.

No comments:

Post a Comment