Genetic diversity of Streptococcus suis strains isolated from pigs and humans as revealed by pulsed-field gel electrophoresis.
The genetic diversity of 123 Streptococcus suis strains of capsular types 2, 1/2, 3, 7, and 9, isolated from pigs in France and from humans in different countries, was evaluated by pulsed-field gel electrophoresis (PFGE) of DNA restricted with SmaI. The method was highly discriminative (D = 0.98), results were reproducible, and the PFGE analysis was easy to interpret. Among all S. suis strains, 74 PFGE patterns were shown. At 60% homology, three groups (A, B, and C) were identified, and at 69% homology, eight subgroups (a to h) were observed. Strains isolated from diseased pigs or from humans were statistically clustered in group B, especially in subgroup d. By contrast, S. suis strains isolated from clinically healthy pigs were preferentially included in subgroup b of group A. Relationships could be established between capsular types 1/2, 3, and 9 and groups A, e, and B, respectively. S. suis strains isolated from humans were homogeneous, and a very high level of association between these strains and four DNA patterns was observed. The PFGE used in this study is a very useful tool for evaluating the genetic diversity of S. suis strains, and it would be used for epidemiological investigations.
Berthelot-Hérault
Florence
F
Agence Française de Sécurité Sanitaire des Aliments, Laboratoire d'Etudes et de Recherches Avicoles et Porcines, Unité de Mycoplasmologie-Bactériologie, 22440 Ploufragan, France.
Marois
Corinne
C
Gottschalk
Marcelo
M
Kobisch
Marylène
M
D000818:Animals; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D016521:Electrophoresis, Gel, Pulsed-Field; D014644:Genetic Variation; D006801:Humans; D016920:Meningitis, Bacterial / Q000382:microbiology*; D013290:Streptococcal Infections / Q000382:microbiology / Q000662:veterinary; D017011:Streptococcus suis / Q000145:classification / Q000235:genetics*; D013552:Swine / Q000382:microbiology*; D013553:Swine Diseases / Q000382:microbiology*
C025651:CCCGGG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific