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Cultivation Methods of Spirochetes from Borrelia burgdorferi Sensu Lato Complex and Relapsing Fever Borrelia
Published on: November 25, 2022
The relapsing fever spirochete Borrelia miyamotoi is cultivable in a modified Kelly-Pettenkofer medium, and is
Alex Wagemakers, Anneke Oei, Michelle M Fikrig
1Center for Experimental and Molecular Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. lyme@amc.uva.nl.
Background:
Borrelia miyamotoi is a relapsing fever spirochete found in Ixodes ticks in North America, Europe, and Asia, and has recently been found to be invasive in humans. Cultivation of this spirochete has not yet been described, but is important for patient diagnostics and scientific purposes. Host specificity of Borrelia species is dependent on resistance to host complement (serum resistance), and since B. miyamotoi has been identified as a human pathogen we were interested whether B. miyamotoi is resistant to human complement.
Methods:
We inoculated B. miyamotoi strains LB-2001 and HT31 in modified-Kelly-Pettenkofer medium with 10% fetal calf serum (MKP-F), and used standard non-laborious Borrelia culture methods to culture the spirochetes. Next, we assessed serum sensitivity by a direct killing assay and a growth inhibition assay.
Results:
We were able to passage B. miyamotoi over 10 times using a standard culture method in MKP-F medium, and found B. miyamotoi to be resistant to human complement. In contrast to B. miyamotoi, Borrelia anserina--a relapsing fever spirochete unrelated to human infection--was serum sensitive.
Conclusions:
Using a variation on MKP medium we were able to culture B. miyamotoi, opening the door to in vitro research into this spirochete. In addition, we describe that B. miyamotoi is resistant to human complement, which might play an important role in pathogenesis. We have also found B. anserina to be sensitive to human complement, which might explain why it is not related to human infection. Summarizing, we describe a novel culture method for B. miyamotoi and show it is resistant to human complement.
Insights
Borrelia miyamotoi, a pathogen found in ticks, can now be cultured in a lab setting. This research also reveals that Borrelia miyamotoi is resistant to human complement, a key factor in its ability to infect humans.
Area of Science:
- Microbiology
- Infectious Diseases
- Bacteriology
Background:
- Borrelia miyamotoi is an invasive relapsing fever spirochete transmitted by Ixodes ticks.
- Cultivation of B. miyamotoi is crucial for diagnostics and research but has not been previously described.
- Understanding serum resistance is key to Borrelia host specificity and pathogenesis.
Purpose of the Study:
- To establish a culture method for Borrelia miyamotoi.
- To determine if Borrelia miyamotoi is resistant to human complement.
Main Methods:
- B. miyamotoi strains were cultured in modified-Kelly-Pettenkofer medium with fetal calf serum (MKP-F).
- Serum sensitivity was assessed using direct killing and growth inhibition assays.
- Borrelia anserina was used as a control for serum sensitivity.
Main Results:
- Successful serial passage of B. miyamotoi (>10 times) was achieved in MKP-F medium.
- B. miyamotoi demonstrated resistance to human complement.
- Borrelia anserina, in contrast, was found to be sensitive to human complement.
Conclusions:
- A novel culture method for B. miyamotoi was developed, enabling in vitro research.
- B. miyamotoi's resistance to human complement is confirmed, suggesting a role in pathogenesis.
- B. anserina's sensitivity to human complement may explain its lack of human infectivity.
