Genomic insights into a foodborne outbreak of Group B Streptococcus in Singapore - and beyond

9/29/2018

Presented by Swaine L. Chen, MD, PhD

Measurable Learning Objectives:
At the conclusion of this presentation, participants should be able to…
1. Understand that GBS can be a foodborne disease
2. Understand current known characteristics and risk factors of foodborne GBS (ST283, associated with raw fish, associated with Southeast Asia)

ABOUT THE PRESENTER:

Swaine L. Chen, MD, PhD
Dr. Swaine Chen is a Senior Research Scientist in Infectious Diseases at GIS and an Assistant Professor of Medicine at the National University of Singapore. He has a broad background in medicine, biology, and chemistry. In his lab, he studies not only why some bacteria cause infections, but also tries to develop new methods so that we can diseases more quickly in the future. Another major aspect of his work is using DNA sequencing to detect and understand outbreaks of infectious diseases, especially those that are unexpected, like the Group B Streptococcus outbreak associated with yu sheng fish in 2015 in Singapore.

Tim Barkham

10/16/2018 02:48:53 am

Very interesting presentation!

If we were to find some GBS ST283 from earlier time periods, is it likely the estimated year of emergence might change significantly?

Isolates differ by very few SNPs despite being isolated over a considerable number of years. What does this tell us?

Marti Perhach

10/16/2018 08:39:18 am

Such an interesting talk! Thank you. Possibly pregnant women in SE Asia are informed to avoid raw fish consumption in pregnancy. What implications would there be for a developing baby if the mother was exposed to ST183 through food consumption during her pregnancy? Could consumption of food with ST183 necessarily cause GI/vaginal colonization?

Swaine Chen

10/16/2018 09:35:57 am

Yes, there's still a lot we don't know. The issues of transmission, risk to mothers and babies, and overall prevalence in Southeast Asia are all open questions. We need more work here! One of the big issues is that we might be seeing the beginning indications that ST283 foodborne disease is a much bigger problem than we realized, even from the Singapore outbreak. Regarding non-foodborne transmission to neonates...we really just have no idea. Presumably it's capable of causing neonatal meningitis like any other GBS. Presumably it's capable of GI/vaginal colonization just like other GBS - we just haven't had the right surveys done in the region where ST283 is found.

Regarding date of emergence, and the other genomic data - the dates may change but the overall conclusion that ST283 is a recently emerged clone will likely not change. We may see the best estimate vary a bit if we find earlier isolates. Regarding the rate of change (seemingly being very low), this has a few interpretations, one of which being that there just isn't much mutation in this lineage compared with other clones of GBS. That seems likely to be true based on data we have so far, but again we're just at the beginning of figuring out how widespread ST283 is.

10/16/2018 01:52:43 pm

You've done some amazing investigative work. GBSI would be glad to help with any crowdsourcing through our website to help find out how widespread ST283 is.

10/16/2018 06:42:40 pm

Hey Marti. We'd love to work together with GBSI on this. Let's talk more after the symposium is over!

10/16/2018 07:13:20 pm

Sounds like a plan :)

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