Spirochetes Borrelia burgdorferi sensu lato are the causative agents of Lyme disease transmitted by the hard ticks of the genus Ixodes. Spirochetes are motile bacteria with typical flat-wave morphology. These features are crucial for efficient dissemination and evasion of immune responses. However, several reports described presence of non-motile atypical morphologies, e.g. rod-shaped forms, looped/ring shaped forms and spherical/cystic forms called round bodies (RBs).  These forms were observed in the cerebral cortex of patient with chronic Lyme neuroborreliosis [1]. Recently, we proved long term survival of Borrelia in patients after extended antibiotic treatment by successful isolation of live spirochetes [2].

Now, we would like to answer questions, (i) whether RBs represent resistant forms of persisting Lyme disease spirochetes and (ii) whether the transformation of flat-waved spirochetes into RBs forms influences the capability to withstand unfavourable environmental conditions.

For this purpose, we studied morphology and three dimensional arrangements of spirochetes isolated from patients by transmission electron microscopy and electron tomography on serial resin sections and negatively stained spirochetes. Next, using a modification of our novel approach combining cryo-fluorescence and cryo-scanning electron microscopy, we interconnect viability assay with visualization of morphology at high resolution [3]. Viability of GFP expressing spirochetes in a response to host sera was assessed using propidium iodide exclusion method. Obtained results confirmed different susceptibility to different host sera, previously described by our colleagues [4]. We confirmed the formation/viability of RB forms under specific conditions. 

Acknowledgment: This work was supported by the TA CR (TE01020118), European FP7 project 278976 ANTIGONE, Czech-BioImaging (LM 2015062)

[1] Miklossy J, Kasas S, Zurn AD, et al. (2008) Persisting atypical and cystic forms of Borrelia burgdorferi and local inflammation in Lyme neuroborreliosis. J Neuroinflammation. 5: 40.

[2] Rudenko N, Golovchenko M, Vancova M, Clark K, Grubhoffer L, JH Oliver Jr. (2016) Isolation of live Borrelia burgdorferi sensu lato spirochetes from patients with undefined disorders and symptoms not typical for Lyme diseases. Clin Microbiol Infect 22: 267.

[3] Strnad M, Elsterová J, Schrenková J, Vancová M, Rego R, Grubhoffer L, Nebesářová J (2015): Correlative cryo-fluorescence and cryo-scanning electron microscopy as a straightforward tool to study host-pathogen interactions. Scientific Reports. Sci Rep. 5:18029.

[4] Tichá L, Golovchenko M, Oliver JH, Grubhoffer L, Rudenko N (2016): Sensitivity of Lyme Borreliosis Spirochetes to Serum Complement of Regular Zoo Animals: Potential Reservoir Competence of Some Exotic Vertebrates. Vector-Borne and Zoonotic Dis 16: 13–19. 

« Back to The 16th European Microscopy Congress 2016

EMC Abstracts - https://emc-proceedings.com/abstract/structure-and-viability-of-atypical-morphological-forms-of-lyme-disease-spirochetes/