Borrelia Explained

Borrelia is a genus of bacteria of the spirochete phylum.[1] Several species cause Lyme disease, also called Lyme borreliosis, a zoonotic, vector-borne disease transmitted by ticks. Other species of Borrelia cause relapsing fever, and are transmitted by ticks or lice, depending on the species of bacteria.[2] A few Borrelia species as Candidatus Borrelia mahuryensis harbor intermediate genetic features between Lyme disease and relapsing fever Borrelia.[3] The genus is named after French biologist Amédée Borrel (1867–1936), who first documented the distinction between a species of Borrelia, B. anserina, and the other known type of spirochete at the time, Treponema pallidum. This bacterium must be viewed using dark-field microscopy,[4] which make the cells appear white against a dark background. Borrelia species are grown in Barbour-Stoenner-Kelly medium. Of 52 known species of Borrelia, 20 are members of the Lyme disease group (with an additional 3 proposed),[5] 29 belong to the relapsing fever group, and two are members of a genetically distinct third group typically found in reptiles.[6] A proposal has been made to split the Lyme disease group based on genetic diversity and move them to their own genus, Borelliella,[7] but this change is not widely accepted. This bacterium uses hard and soft ticks and lice as vectors.[8] [9] Testing for the presence of the bacteria in a human includes two-tiered serological testing, including immunoassays and immunoblotting.[10]

Biology

Borrelia species are members of the family Spirochaetaceae, so present the characteristic spirochete (spiral) shape. Most species are obligate anaerobes, although some are aerotolerant.[11] Borrelia species have an outer membrane that contains a substance similar to lipopolysaccharides, an inner membrane, and a layer of peptidoglycan in a periplasmic space, which classifies them as Gram-negative. However, this result is not easily visualized using Gram staining. They are typically 20–30 μm long and 0.2–0.3 μm wide.

Spirochetes move using axial filaments called endoflagella in their periplasmic space. The filaments rotate in this space, between the outer membrane and the peptidoglycan layer, propelling the bacterium forward in a corkscrew-like motion. The outer membrane of Borrelia species contains outer surface proteins (Osp) that play a role in their virulence.

Phylogeny

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN)[12] and National Center for Biotechnology Information (NCBI).[13]

Species incertae sedis::

Vectors

Ticks

Hard ticks of the family Ixodidae are common vectors of Borellia bacteria[20] and are the only type of ticks shown to transmit Lyme disease bacteria to humans.[21] Some tick species of the Ambylomma genus are vectors of Candidatus Borrelia mahuryensis in South America.

Global hard tick species that cause Lyme disease!Region!Tick species!Common name
East and Midwest (US)Ixodes scapularisBlack-legged tick, deer tick
Pacific Coast (US)Ixodes pacificusWestern black-legged tick
EuropeIxodes ricinusSheep tick
AsiaIxodes persulcatusTaiga tick
Other species are carried by soft ticks. The soft tick Ornithodoros carries the species of Borellia that cause relapsing fever. Another species, B. anserina, is carried by the soft tick Argas. Inside the ticks, the bacteria grow in the midgut and then travel to the salivary glands to be transmitted to a new host. Ticks can spread the bacteria to each other when co-feeding. If an animal has been infected by a tick and then is bitten by a second tick, the second tick can become infected.[22] The bacteria are most commonly transmitted to humans through ticks in the nymph stage of development, because they are smaller and less likely to be noticed and removed. The ticks must have around 36 to 48 hours of contact with a host to successfully transmit the bacteria.

Lice

Lice that feed on infected humans acquire the Borrelia organisms that then multiply in the hemolymph and gut of the lice. When an infected louse feeds on an uninfected human, the organism gains access when the victim crushes the louse or scratches the area where the louse is feeding. The U. S. Centers for Disease Control and Prevention reported that no credible evidence shows that lice can carry Borrelia.

Pathology

Lyme disease

See main article: Lyme disease microbiology.

Of the 52 known species of Borrelia, 20 belong to the Lyme disease group and are transmitted by ticks. Eight are known to cause Lyme disease or Borreliosis.[5] The major Borrelia species causing Lyme disease are Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii.[23] All species that cause Lyme disease are referred to collectively as B. burgdorferi sensu lato, while B. burgdorferi itself is specified as B. burgdorferi sensu stricto. B. burgdorferi was previously believed to be the only species to cause Lyme disease in the US, but B. bissettiae and a new species called B. mayonii cause Lyme disease in the US, as well. The remaining five human pathogenic species occur only in Europe and Asia.

Relapsing fever

See main article: Relapsing fever.

Relapsing fever (RF) borreliosis often occurs with severe bacteremia.[24] Twenty-five species of Borrelia are known to cause relapsing fever.[25] While most species use the soft tick family Argasidae as their vector, some outliers live in hard ticks or lice. Relapsing fever can be spread epidemically through lice or endemically through ticks.

B. recurrentis, a common species underlying relapsing fever, is transmitted by the human body louse; no other animal reservoir of B. recurrentis is known. B. recurrentis infects the person via mucous membranes and then invades the bloodstream.

Other tick-borne relapsing infections are acquired from other species, such as B. hermsii, B. parkeri, or B. miyamotoi,[26] which can be spread from rodents, and serve as a reservoir for the infection, via a tick vector. B. hermsii and B. recurrentis cause very similar diseases, although the disease associated with B. hermsii has more relapses and is responsible for more fatalities, while the disease caused by B. recurrentis has longer febrile and afebrile intervals and a longer incubation period.

Borellia miyamotoi disease

See also: Borrelia miyamotoi.

Diagnosis

Direct tests include culture of Borrelia from skin, blood, or cerebrospinal fluid (CSF), and detection of genetic material by polymerase chain reaction in skin, blood, or synovial fluid. Two-tiered serological testing is performed for differential diagnosis of Borrelia infection. The first-tier tests detect specific antibodies (IgM and IgG together or separately) and include enzyme-linked immunoassays (e.g. ELISAs) and immunofluorescent assays. Positive results for first-tier tests are confirmed using second-tier testing. The second tier consists of standardized immunoblotting, either by using Western blots or blots striped with diagnostically important purified antigens. Positive results for second-tier tests are confirmatory for the presence of Borrelia infection.[27] Spirochetes can also be seen using Wright-stained blood smears.

See also

Further reading

External links

Notes and References

  1. Parte AC . LPSN--list of prokaryotic names with standing in nomenclature . Nucleic Acids Research . 42 . Database issue . D613–D616 . January 2014 . 24243842 . 3965054 . 10.1093/nar/gkt1111 .
  2. Book: Radolf JD, Samuels DS . 2021 . Lyme Disease and Relapsing Fever Spirochetes: Genomics, Molecular Biology, Host Interactions, and Disease Pathogenesis . Caister Academic Press . 978-1-913652-61-6.
  3. Binetruy F, Garnier S, Boulanger N, Talagrand-Reboul É, Loire E, Faivre B, Noël V, Buysse M, Duron O . 6 . A novel Borrelia species, intermediate between Lyme disease and relapsing fever groups, in neotropical passerine-associated ticks . Scientific Reports . 10 . 1 . 10596 . June 2020 . 32606328 . 7327063 . 10.1038/s41598-020-66828-7 . 2020NatSR..1010596B .
  4. Book: Todar's Online Textbook of Bacteriology. Todar K . 2006. University of Wisconsin-Madison Department of Bacteriology. 803733454.
  5. Wolcott KA, Margos G, Fingerle V, Becker NS . Host association of Borrelia burgdorferi sensu lato: A review . Ticks and Tick-Borne Diseases . 12 . 5 . 101766 . September 2021 . 34161868 . 10.1016/j.ttbdis.2021.101766 .
  6. Cutler SJ, Ruzic-Sabljic E, Potkonjak A . Emerging borreliae - Expanding beyond Lyme borreliosis . Molecular and Cellular Probes . 31 . 22–27 . February 2017 . 27523487 . 10.1016/j.mcp.2016.08.003 .
  7. Adeolu M, Gupta RS . A phylogenomic and molecular marker based proposal for the division of the genus Borrelia into two genera: the emended genus Borrelia containing only the members of the relapsing fever Borrelia, and the genus Borreliella gen. nov. containing the members of the Lyme disease Borrelia (Borrelia burgdorferi sensu lato complex) . Antonie van Leeuwenhoek . 105 . 6 . 1049–1072 . June 2014 . 24744012 . 10.1007/s10482-014-0164-x .
  8. Shapiro ED . Borrelia burgdorferi (Lyme disease) . Pediatrics in Review . 35 . 12 . 500–509 . December 2014 . 25452659 . 5029759 . 10.1542/pir.35-12-500 . Elsevier . 9780702034688 . vanc .
  9. Book: Petri WA . 330 - Relapsing Fever and Other Borrelia Infections . Goldman's Cecil Medicine . 2 . 2012 . 1935–1937 . Twenty-Fourth . 10.1016/b978-1-4377-1604-7.00330-4 . 9781437716047 .
  10. Marques AR . Laboratory diagnosis of Lyme disease: advances and challenges . Infectious Disease Clinics of North America . 29 . 2 . 295–307 . June 2015 . 25999225 . 4441761 . 10.1016/j.idc.2015.02.005 .
  11. De Martino SJ, Sordet C, Piémont Y, Ruzic-Sabljic E, Thaddée Vetter M, Monteil H, Sibilia J, Jaulhac B . 6 . Enhanced culture of Borrelia garinii and Borrelia afzelii strains on a solid BSK-based medium in anaerobic conditions . Research in Microbiology . 157 . 8 . 726–729 . October 2006 . 16814991 . 10.1016/j.resmic.2006.05.002 . free .
  12. Web site: J.P. Euzéby . Borrelia . 2021-03-20 . List of Prokaryotic names with Standing in Nomenclature (LPSN).
  13. Web site: Sayers . Borrelia . 2021-03-20 . National Center for Biotechnology Information (NCBI) taxonomy database. et al..
  14. Web site: The LTP . 20 November 2023.
  15. Web site: LTP_all tree in newick format. 20 November 2023.
  16. Web site: LTP_08_2023 Release Notes. 20 November 2023.
  17. Web site: GTDB release 08-RS214 . Genome Taxonomy Database. 10 May 2023.
  18. Web site: bac120_r214.sp_label . Genome Taxonomy Database. 10 May 2023.
  19. Web site: Taxon History . Genome Taxonomy Database. 10 May 2023.
  20. Heylen D, Lasters R, Adriaensen F, Fonville M, Sprong H, Matthysen E . Ticks and tick-borne diseases in the city: Role of landscape connectivity and green space characteristics in a metropolitan area . The Science of the Total Environment . 670 . 941–949 . June 2019 . 30921726 . 10.1016/j.scitotenv.2019.03.235 . 2019ScTEn.670..941H . 85564512 .
  21. Tilly K, Rosa PA, Stewart PE . Biology of infection with Borrelia burgdorferi . Infectious Disease Clinics of North America . 22 . 2 . 217–34, v . June 2008 . 18452798 . 2440571 . 10.1016/j.idc.2007.12.013 .
  22. Web site: Transmission Lyme Disease CDC. 2019-02-06. www.cdc.gov. en-us. 2019-04-03.
  23. Web site: Borrelia mayonii Ticks CDC. 2019-01-10. www.cdc.gov. en-us. 2019-04-03.
  24. Guo BP, Teneberg S, Münch R, Terunuma D, Hatano K, Matsuoka K, Angström J, Borén T, Bergström S . 6 . Relapsing fever Borrelia binds to neolacto glycans and mediates rosetting of human erythrocytes . Proceedings of the National Academy of Sciences of the United States of America . 106 . 46 . 19280–19285 . November 2009 . 19884498 . 2771742 . 10.1073/pnas.0905470106 . free . 2009PNAS..10619280G .
  25. Book: Wang G . Chapter 104 - Borrelia burgdorferi and Other Borrelia Species . Molecular Medical Microbiology . Second . 3 . 2015 . 1867–1909 . 10.1016/b978-0-12-397169-2.00104-9 . 9780123971692 .
  26. News: McNeil D . New Tick-Borne Disease Is Discovered . The New York Times . D6 . 19 September 2011 . 20 September 2011.
  27. Johnson BJ, Robbins KE, Bailey RE, Cao BL, Sviat SL, Craven RB, Mayer LW, Dennis DT . 6 . Serodiagnosis of Lyme disease: accuracy of a two-step approach using a flagella-based ELISA and immunoblotting . The Journal of Infectious Diseases . 174 . 2 . 346–353 . August 1996 . 8699065 . 10.1093/infdis/174.2.346 . free .

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