Genetic diversity and variation in antimicrobial-resistance determinants of non-serotype 2 Streptococcus suis isolates from healthy pigs

Nattinee Kittiwan, Jessica K. Calland, Evangelos Mourkas, Matthew D. Hitchings, Susan Murray, Pakpoom Tadee, Phacharaporn Tadee, Kwanjit Duangsonk, Guillaume Meric, Samuel K. Sheppard, Prapas Patchanee, Ben Pascoe

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4 Citations (SciVal)


Streptococcus suis is a leading cause of bacterial meningitis in South-East Asia, with frequent zoonotic transfer to humans associated with close contact with pigs. A small number of invasive lineages are responsible for endemic infection in the swine industry, causing considerable global economic losses. A lack of surveillance and a rising trend in clinical treatment failure has raised concerns of growing antimicrobial resistance (AMR) among invasive S. suis. Gene flow between healthy and disease isolates is poorly understood and, in this study, we sample and sequence a collection of isolates predominantly from healthy pigs in Chiang Mai province, Northern Thailand. Pangenome characterization identified extensive genetic diversity and frequent AMR carriage in isolates from healthy pigs. Multiple AMR genes were identified, conferring resistance to aminoglycosides, lincosamides, tetracycline and macrolides. All isolates were non-susceptible to three or more different antimicrobial classes, and 75% of non-serotype 2 isolates were non-susceptible to six or more classes (compared to 37.5% of serotype 2 isolates). AMR genes were found on integrative and conjugative elements previously observed in other species, suggesting a mobile gene pool that can be accessed by invasive disease isolates. This article contains data hosted by Microreact.

Original languageEnglish
Article number000882
JournalMicrobial Genomics
Issue number11
Publication statusPublished - 3 Nov 2022

Bibliographical note

Funding Information:
This research work was partially supported by Chiang Mai University (Thailand) and the National Science and Technology Development Agency (P-13-50155). All high-performance computing was performed in collaboration with Medical Research Council (MRC) CLIMB, funded by the MRC (MR/ L015080/1 and MR/T030062/1). Collaborative visits between UK and Thai partners were supported by a Newton Fund Researcher Links travel grant. The funders played no role in study design nor implementation.


  • antimicrobial resistance
  • gene pool transmission
  • meningitis
  • One Health
  • Streptococcus suis

ASJC Scopus subject areas

  • Epidemiology
  • Microbiology
  • Molecular Biology
  • Genetics


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