title: Virulence in mice of pneumococcal clonal types with known invasive disease potential in humans.
abstract: Streptococcus pneumoniae isolates of serotypes 1, 4, 6B, 7F, 14, and 19F belonging to clonal types with known invasive disease potential in humans were used to infect C57BL/6 and BALB/c mice. Most isolates were able to colonize the nasopharynx for 7 days. One serotype 19F isolate of the clonal type ST162 had higher bacterial numbers than other isolates and clonal types of the same serotype. Serotype 4 clones caused the most-severe invasive disease, whereas serotype 1 clones caused low-level bacteremia without disease symptoms. BALB/c mice were more likely than C57BL/6 mice to develop meningitis. Disease kinetics varied significantly between clonal types. Although most induced a robust tumor necrosis factor response, some isolates of serotype 1 and 7F did not, suggesting that invasive disease caused by different clonal types may result in different degrees of host response. Capsular serotype, other clonal properties, and host factors are important for the development of pneumococcal disease.
authors.affiliation: Swedish Institute for Infectious Disease Control, Solna, Sweden.
authors.forename: Andreas
authors.initials: A
authors.lastname: Sandgren
authors.forename: Barbara
authors.initials: B
authors.lastname: Albiger
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Orihuela
authors.forename: Elaine
authors.initials: E
authors.lastname: Tuomanen
authors.forename: Staffan
authors.initials: S
authors.lastname: Normark
authors.forename: Birgitta
authors.initials: B
authors.lastname: Henriques-Normark
mesh_terms: D000818:Animals; D016470:Bacteremia / Q000276:immunology / Q000382:microbiology; D016667:Bacterial Capsules / Q000502:physiology; D002999:Clone Cells; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008164:Luminescent Proteins / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011008:Pneumococcal Infections / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000472:pathogenicity* / Q000502:physiology; D016019:Survival Analysis; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology; D014774:Virulence
chemical_list: D008164:Luminescent Proteins; D014409:Tumor Necrosis Factor-alpha