Borrelia Burgdorferi: Lyme Disease
Borrelia burgdorferi
Overview:
Lyme disease was first recognized in the United States in 1975 by Dr. Allen Steere, following a mysterious outbreak of juvenile rheumatoid arthritis near the community of Lyme, Connecticut. The rural location of the Lyme outbreak and the onset of illness during summer and early fall suggested that the transmission of the disease was by an arthropod vector. Adult female Ixodes tick (deer tick) From Brown University In 1982, the causative agent of Lyme disease was discovered by Willy Burgdorfer, who isolated spirochetes belonging to the genus Borrelia from the mid-guts of the species Ixodes ticks. Spirochettes are pleomorphic. They appear spiral-shaped, but have evolved the capacity to hide …show more content…
burgdorferi is a helical shaped spirochete bacterium. It has an inner and outer membrane as well as a flexible cell wall. Inside the bacteria 's cell membranes is the protoplasm, which, due to the spiral shape of the bacteria, is long and cylindrical. Spirochete bacteria such as B. burgdorferi have a unique structural characteristic. The cell 's flagella are located inside the periplasm between the inner and outer cell membranes. The interactions between the flagella and cell cylinder allows the cell to travel through highly viscous fluids and materials. This adaptation is especially critical for the ability of B. burgdorferi to travel through the tissue of its infected host or vector, causing it to be highly …show more content…
burgdorferi as compared with other bacteria is its unusual genome, which includes a linear chromosome and numerous linear and circular plasmids. Long-term culture of B. burgdorferi results in a loss of some plasmids and changes in expressed proteins. The loss of plasmids results in the organism’s loss of ability to infect laboratory animals, suggesting that the plasmids encode key genes involved in virulence.
Cultivation
Unlike Treponema pallidum, Borrelia burgdorferi can be cultivated in vitro. However, the bacterium is fastidious and requires a very complex growth medium. The medium used to grow Borrelia burgdorferi is called Barbour-Stoenner-Kelly (BSK) medium. It contains over thirteen ingredients in a rabbit serum base. Borrelia burgdorferi has an optimal temperature for growth of 32oC, in a microaerobic environment. Even under optimal conditions, the generation time is slow, about 12-24 hours. Borreliae from ticks and from the blood, skin, and cerebrospinal fluid of Lyme disease patients have been successfully cultivated in BSK medium. BSK solidified with 1.3% agarose allows the production of colonies from single organisms.
Outer Surface Proteins The outer membrane of Borrelia burgdorferi is composed of various unique outer surface proteins (Osp) and are thought to play a role in virulence. Osp A and Osp B are by far the most abundant outer surface
Overview:
Lyme disease was first recognized in the United States in 1975 by Dr. Allen Steere, following a mysterious outbreak of juvenile rheumatoid arthritis near the community of Lyme, Connecticut. The rural location of the Lyme outbreak and the onset of illness during summer and early fall suggested that the transmission of the disease was by an arthropod vector. Adult female Ixodes tick (deer tick) From Brown University In 1982, the causative agent of Lyme disease was discovered by Willy Burgdorfer, who isolated spirochetes belonging to the genus Borrelia from the mid-guts of the species Ixodes ticks. Spirochettes are pleomorphic. They appear spiral-shaped, but have evolved the capacity to hide …show more content…
burgdorferi is a helical shaped spirochete bacterium. It has an inner and outer membrane as well as a flexible cell wall. Inside the bacteria 's cell membranes is the protoplasm, which, due to the spiral shape of the bacteria, is long and cylindrical. Spirochete bacteria such as B. burgdorferi have a unique structural characteristic. The cell 's flagella are located inside the periplasm between the inner and outer cell membranes. The interactions between the flagella and cell cylinder allows the cell to travel through highly viscous fluids and materials. This adaptation is especially critical for the ability of B. burgdorferi to travel through the tissue of its infected host or vector, causing it to be highly …show more content…
burgdorferi as compared with other bacteria is its unusual genome, which includes a linear chromosome and numerous linear and circular plasmids. Long-term culture of B. burgdorferi results in a loss of some plasmids and changes in expressed proteins. The loss of plasmids results in the organism’s loss of ability to infect laboratory animals, suggesting that the plasmids encode key genes involved in virulence.
Cultivation
Unlike Treponema pallidum, Borrelia burgdorferi can be cultivated in vitro. However, the bacterium is fastidious and requires a very complex growth medium. The medium used to grow Borrelia burgdorferi is called Barbour-Stoenner-Kelly (BSK) medium. It contains over thirteen ingredients in a rabbit serum base. Borrelia burgdorferi has an optimal temperature for growth of 32oC, in a microaerobic environment. Even under optimal conditions, the generation time is slow, about 12-24 hours. Borreliae from ticks and from the blood, skin, and cerebrospinal fluid of Lyme disease patients have been successfully cultivated in BSK medium. BSK solidified with 1.3% agarose allows the production of colonies from single organisms.
Outer Surface Proteins The outer membrane of Borrelia burgdorferi is composed of various unique outer surface proteins (Osp) and are thought to play a role in virulence. Osp A and Osp B are by far the most abundant outer surface