Comparison of the susceptibilities of C57BL/6 and A/J mouse strains to Streptococcus suis serotype 2 infection.
Streptococcus suis is an important swine and human pathogen. Assessment of susceptibility to S. suis using animal models has been limited to monitoring mortality rates. We recently developed a hematogenous model of S. suis infection in adult CD1 outbred mice to study the in vivo development of an early septic shock-like syndrome that leads to death and a late phase that clearly induces central nervous system damage, including meningitis. In the present study, we compared the severities of septic shock-like syndrome caused by S. suis between adult C57BL/6J (B6) and A/J inbred mice. Clinical parameters, proinflammatory mediators, and bacterial clearance were measured to dissect potential immune factors associated with genetic susceptibility to S. suis infection. Results showed that A/J mice were significantly more susceptible than B6 mice to S. suis infection, especially during the acute septic phase of infection (100% of A/J and 16% of B6 mice died before 24 h postinfection). The greater susceptibility of A/J mice was associated with an exaggerated inflammatory response, as indicated by their higher production of tumor necrosis factor alpha, interleukin-12p40/p70 (IL-12p40/p70), gamma interferon, and IL-1beta, but not with different bacterial loads in the blood. In addition, IL-10 was shown to be responsible, at least in part, for the higher survival in B6 mice. Our findings demonstrate that A/J mice are very susceptible to S. suis infection and provide evidence that the balance between pro- and anti-inflammatory mediators is crucial for host survival during the septic phase.
Domínguez-Punaro
María de la Cruz
Mde L
Faculté de Médecine Vétérinaire, Groupe de Recherche sur les Maladies Infectieuses du Porc, Centre de Recherche en Infectiologie Porcine, Université de Montréal, St-Hyacinthe, QC J2S 7C6, Canada.
Segura
Mariela
M
Radzioch
Danuta
D
Rivest
Serge
S
Gottschalk
Marcelo
M
D000818:Animals; D016470:Bacteremia; D001769:Blood / Q000276:immunology / Q000382:microbiology; D001921:Brain / Q000473:pathology; D016207:Cytokines / Q000097:blood; D004198:Disease Susceptibility; D005260:Female; D008578:Meninges / Q000473:pathology; D051379:Mice; D008805:Mice, Inbred A; D008810:Mice, Inbred C57BL; D009206:Myocardium / Q000473:pathology; D012720:Severity of Illness Index; D012772:Shock, Septic / Q000382:microbiology* / Q000503:physiopathology*; D013045:Species Specificity; D013290:Streptococcal Infections / Q000276:immunology* / Q000503:physiopathology*; D017011:Streptococcus suis / Q000502:physiology*; D016019:Survival Analysis
D016207:Cytokines