Oral Presentation 20th Lancefield International Symposium on Streptococci and Streptococcal Diseases 2017

Human Streptococcus suis infections in South East Asia: Do we have molecular evidence for transboundary zoonotic infections? (#93)

Ha N Huynh 1 , CHIEU TB TRAN 1 , Erika Vlieghe 2 , Sayaphet Rattanavong 3 , Ngoc B Vuong 1 , V. Davong 3 , R. Phetsouvanh 3 , Uyen N Phan 1 , Paul N Newton 3 4 , Birgit D Smet 2 , Phong The 5 , Phu H Nguyen 6 , Chau VV Nguyen 6 , David Dance 3 4 7 , Jan Jacobs 2 , Hoa T Ngo 1 4 8
  1. Oxford University Clinical Research Unit, Vietnam, HCMC, Viet Nam
  2. Institute of Tropical Medicine , Antwerp, Belgium
  3. Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Vientiane, Laos
  4. Centre for Tropical Medicine and Global Health, Nuffield Department of Tropical medicine University of Oxford, Oxford, UK
  5. Sihanouk Hospital Centre of Hope, Phnom Penh, Cambodia
  6. Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
  7. Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
  8. Department of Biology and Biotechnology, University of Science, HCMC National University, HCMC, Vietnam

Streptococcus suis is a major emerging zoonotic pathogen which causes over 1600 systemic infections in humans globally. Clinical syndromes include meningitis and sepsis which can be fatal due to septic shock in 13% of patients. Occupational exposure to pigs or pork and consumption of high risk pork dishes are reported risk factors for human S. suis infections in Asia. S. suis serotype 2 strains were detected in more than 65% of 188 tested samples of fresh blood pudding. S. suis isolated from these samples carried the virulence genes cps2J, mrp, epf and sly. Serological studies in Vietnam suggested the existence of mild or sub-clinical S. suis infections in healthy people who may or may not have a history of pig exposure. Over 90% of human systemic infections with S. suis have been reported from Asia, mainly sporadic cases in Thailand and Vietnam. In recent years, more than a dozen systemic S. suis infections have been microbiologically confirmed in both Cambodia and Laos. Molecular analysis using multi-locus sequence typing (MLST) and pulse field gel electrophoresis (PFGE) suggest that S. suis isolates from patients from Cambodia (ST1) and Laos (ST104) share identical PFGE band patterns with those from Vietnam and Thailand, respectively. Cross-national pig trade between these countries exists in both formal and informal forms and may be correlated to these pig-related zoonotic infections. Analysis of whole genome sequence data may help to reveal the genetic relationships of these strains to provide further evidence for potential transboundary zoonotic transmission of S. suis.