Title of the talk: Streptococcus agalactiae appears to be primarily a foodborne infection, associated with aquaculture, in parts of Southeast Asia
In Singapore in 2015 Streptococcus agalactiae (GBS) serotype III, Sequence Type (ST) 283 caused the first reported foodborne outbreak of invasive GBS; it was acquired from farmed fish. Cases included meningitis and septic arthritis amongst young adults with few co-morbidities. Previously, ST283 had only been reported from humans in Hong Kong and one fish in Thailand. We investigated the extent of ST283. We reviewed the literature. Whole genome sequencing was used to assess the phylogeny of ST283 found in human and/or animal collections. The ST283 clone accounted for 20-70% of all invasive human GBS in countries in SE Asia between 2000 and 2017, but only four reports were found outside Asia. GBS bacteraemia rates in Thailand and Lao PDR were triple those in the UK; the excess was ST283. All 62 (100%) GBS from fourteen fish farms in Malaysia and Vietnam were ST283. ST283 was found in a diseased frog in China. Serotype III GBS causing die offs in fish farms in Thailand between 2003-2006, and Brazil in 2016, are suspected to be ST283, but it is absent from other animal reports, globally.
GBS ST283 is widespread in SE Asia, amongst humans and fish. It causes the majority of adult human GBS invasive disease in some countries. The implication is that GBS is primarily a foodborne disease in some parts of Asia. Consumption of raw fish was the cause in the Singapore outbreak, and fish is the prime suspect in the rest of SE Asia.
Dr Barkham studied medicine and then specialised as a Microbiologist at St. Thomas’ Hospital in London. He then worked at the Hammersmith Hospitals for two years before moving to Singapore in 1999. He enjoys clinical infectious diseases, epidemiology and outbreak investigation. He has a 20% teaching appointment at the National University of Singapore. He has developed diagnostic assays that are marketed in Singapore and elsewhere in Asia.