Genomic and pathogenic investigations of Streptococcus suis serotype 7 population derived from a human patient and pigs

• Published in: Emerging microbes & infections Vol. 10; no. 1; pp. 1960 - 1974
• Main Authors: Liang, Pujun, Wang, Mingliu, Gottschalk, Marcelo, Vela, Ana I., Estrada, April A., Wang, Jianping, Du, Pengcheng, Luo, Ming, Zheng, Han, Wu, Zongfu
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 01.01.2021; Taylor & Francis Group
• Subjects: Aged; Animals; Anti-Bacterial Agents - pharmacology; Bacteremia - microbiology; Bacterial Zoonoses - microbiology; China; Disease Models, Animal; Drug Resistance, Multiple, Bacterial - genetics; Female; Genome, Bacterial - genetics; Humans; integrative mobilizable elements; Interspersed Repetitive Sequences - genetics; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests; Multilocus Sequence Typing; Phylogeny; Pneumonia, Bacterial - microbiology; Polymorphism, Single Nucleotide - genetics; Serogroup; Streptococcal Infections - microbiology; Streptococcus suis - drug effects; Streptococcus suis - genetics; Streptococcus suis - isolation & purification; Streptococcus suis - pathogenicity; Streptococcus suis serotype 7; Swine; Swine Diseases - microbiology; Virulence; Virulence Factors - genetics; zoonotic pathogens; China; integrative mobilizable elements; Streptococcus suis serotype 7; phylogeny; zoonotic pathogens; virulence
• ISSN: 2222-1751; 2222-1751
• DOI: 10.1080/22221751.2021.1988725

Streptococcus suis is one of the important emerging zoonotic pathogens. Serotype 2 is most prevalent in patients worldwide. In the present study, we first isolated one S. suis serotype 7 strain GX69 from the blood culture of a patient with septicemia complicated with pneumonia in China. In order to deepen the understanding of S. suis serotype 7 population characteristics, we investigated the phylogenetic structure, genomic features, and virulence of S. suis serotype 7 population, including 35 strains and 79 genomes. Significant diversities were revealed in S. suis serotype 7 population, which were clustered into 22 sequence types (STs), five minimum core genome (MCG) groups, and six lineages. Lineages 1, 3a, and 6 were mainly constituted by genomes from Asia. Genomes of Lineages 2, 3b, and 5a were mainly from Northern America. Most of genomes from Europe (41/48) were clustered into Lineage 5b. In addition to strain GX69, 13 of 21 S. suis serotype 7 representative strains were classified as virulent strains using the C57BL/6 mouse model. Virulence-associated genes preferentially present in highly pathogenic S. suis serotype 2 strains were not suitable as virulence indicators for S. suis serotype 7 strains. Integrative mobilizable elements were widespread and may play a critical role in disseminating antibiotic resistance genes of S. suis serotype 7 strains. Our study confirmed S. suis serotype 7 is a non-negligible pathotype and deepened the understanding of the population structure of S. suis serotype 7, which provided valuable information for the improved surveillance of this serotype.