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Updated: Aug 14, 2026
A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
The multiplication of three different isolates of group B streptococci in pregnant mice
Abstract:
The ability of three streptococcal isolates of different pathogenicity to multiply in the tissues of pregnant mice was investigated following intravenous injection. The highly pathogenic isolate multiplied most rapidly whilst the isolate of low pathogenicity showed the least rapid growth within the observation period of 24 hours. The greatest concentration of streptococci per gram of tissue was found in the placentae of mice injected with the highly pathogenic and moderately pathogenic isolates when compared with the concentration of livers and spleen. Fetal infection did not occur within 24 hours of intravenous injection of the isolates but retarded fetal growth and infection was demonstrable five days after the injection. The isolate of moderate pathogenicity infected a greater proportion of the fetuses than the isolates of low pathogenicity. It is suggested that the outcome of streptococcal infections by the ability of isolates to multiply in host tissues.
Insights
Streptococcal pathogenicity in pregnant mice correlates with tissue multiplication rates. Highly pathogenic strains showed rapid growth, leading to placental infection and retarded fetal development within five days.
Area of Science:
- Microbiology
- Immunology
- Perinatal Medicine
Background:
- Streptococcal infections pose risks during pregnancy.
- Understanding bacterial pathogenicity is crucial for maternal and fetal health.
Purpose of the Study:
- To investigate the tissue multiplication and pathogenicity of different streptococcal isolates in pregnant mice.
- To determine the impact of streptococcal isolates on fetal growth and infection.
Main Methods:
- Intravenous injection of three streptococcal isolates with varying pathogenicity into pregnant mice.
- Monitoring bacterial growth in maternal tissues (liver, spleen, placenta) over 24 hours.
- Assessing fetal growth and infection rates at 24 hours and five days post-injection.
Main Results:
- Highly pathogenic streptococci multiplied most rapidly in maternal tissues.
- Placentae showed the highest bacterial concentration with pathogenic and moderately pathogenic isolates.
- Fetal growth was retarded, and infection was evident by five days, with moderate isolates infecting more fetuses.
Conclusions:
- Streptococcal isolate pathogenicity is linked to its ability to multiply within host tissues.
- Bacterial multiplication in placental tissues contributes to adverse fetal outcomes.
- The capacity for rapid tissue proliferation is a key factor in streptococcal virulence during pregnancy.
