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Updated: Jun 12, 2026
Microscopy-based Assays for High-throughput Screening of Host Factors Involved in Brucella Infection of Hela Cells
Published on: August 5, 2016
The new species Brucella microti replicates in macrophages and causes death in murine models of infection
María P Jiménez de Bagüés1, Safia Ouahrani-Bettache, Juan F Quintana
1Unidad de Sanidad Animal, Centro de Investigación y Tecnología Agroalimentaria, Gobierno de Aragón, Zaragoza, Spain.
Background:
The recent isolation of Brucella microti from the common vole, the red fox, and the soil raises the possibility of an eventual reemergence of brucellosis in Europe. In this work, the pathogenic potential of this new Brucella species in both in vitro and in vivo models of infection was analyzed.
Methods:
The ability of B. microti (as compared to that of the closely related species Brucella suis) to replicate in human macrophages and in human and murine macrophage-like cells was determined. The behavior of B. microti and B. suis was evaluated in vivo in murine models of infection with Balb/c, CD1, and C57BL/6 mice.
Results:
B. microti showed an enhanced capacity for intramacrophagic replication compared with that of B. suis. Surprisingly, and in contrast to other species of Brucella, 10(5) colony-forming units of B. microti killed 82% of Balb/c mice within 7 days. Infection of spleen and liver with B. microti peaked at day 3, compared with B. suis infection, which peaked at day 7. Sublethal doses of B. microti induced good protection against a subsequent challenge with lethal doses.
Conclusions:
In experimental cellular and murine infections, B. microti exhibited a high pathogenic potential, compared with other Brucella species.
Insights
Brucella microti, a newly isolated bacterium, demonstrates significant pathogenic potential in experimental models. This bacterium shows enhanced replication in macrophages and high virulence in mice, suggesting a potential brucellosis reemergence risk.
Area of Science:
- Microbiology
- Infectious Diseases
- Veterinary Medicine
Background:
- Brucella microti has been recently isolated from voles, foxes, and soil in Europe.
- This raises concerns about a potential resurgence of brucellosis in the region.
Purpose of the Study:
- To analyze the pathogenic potential of Brucella microti.
- To compare its virulence with the closely related species Brucella suis.
Main Methods:
- In vitro assessment of intramacrophagic replication in human and murine macrophage-like cells.
- In vivo evaluation of virulence in different mouse strains (Balb/c, CD1, C57BL/6).
Main Results:
- B. microti exhibited greater replication within macrophages than B. suis.
- A low dose of B. microti (10^5 CFU) was lethal to 82% of Balb/c mice within 7 days.
- B. microti infection kinetics in spleen and liver differed from B. suis, peaking earlier.
Conclusions:
- Brucella microti possesses a high pathogenic potential in experimental infections.
- Its virulence in vitro and in vivo surpasses that of other Brucella species, warranting further investigation.
