[Borrelia burgdorferi s.s. length and its variability]

Area of Science:

• Microbiology
• Parasitology
• Infectious Diseases

Background:

• Borrelia burgdorferi sensu lato (s.l.) and Borrelia burgdorferi sensu stricto (s.s.) are tick-borne spirochetes responsible for Lyme disease.
• The morphology and infectivity of these bacteria can be influenced by environmental factors and laboratory cultivation.
• Understanding variations in Borrelia burgdorferi is crucial for assessing disease risk and developing diagnostic tools.

Purpose of the Study:

• To measure the length of Borrelia burgdorferi s.l. and s.s. under various conditions.
• To investigate the relationship between Borrelia burgdorferi length and its pathogenicity in a murine model.
• To determine if bacterial length can serve as a reliable marker for pathogenicity.

Main Methods:

• Measurement of Borrelia burgdorferi s.l. and s.s. lengths from ticks collected in the Moscow Region and laboratory cultures.
• Cultivation of Borrelia burgdorferi s.s. on BSK-II medium over multiple passages (1 and 10).
• Assessment of Borrelia burgdorferi pathogenicity in albino mice after exposure to bacteria stored in ticks or cultured in vitro.

Main Results:

• Observed a wide range of Borrelia burgdorferi lengths (3-74 microns), with average sizes varying from 10.7 to 24.8 microns.
• Bacterial length decreased to 10.7-10.9 microns when ticks were stored for 1-2 years in a refrigerator.
• Length increased to 24.8 microns after 10 passages on BSK-II medium; reduced length correlated with diminished pathogenicity in mice, which disappeared after extensive culturing.

Conclusions:

• Bacterial length in Borrelia burgdorferi exhibits significant variability influenced by storage conditions and in vitro cultivation.
• Reduced bacterial length, particularly after prolonged tick storage, is associated with decreased pathogenicity.
• Bacterial length may serve as a potential indicator or marker for the infectivity and pathogenicity of Borrelia burgdorferi.