| 1. |
- Nordstrand, Annika, et al.
(författare)
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Tickborne relapsing fever diagnosis obscured by malaria, Togo.
- 2007
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Ingår i: Emerging Infectious Diseases. - 1080-6040 .- 1080-6059. ; 13:1, s. 117-123
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Tidskriftsartikel (refereegranskat)abstract
- Given the prevalence of relapsing fever (RF) in Senegal, this disease may cause illness and death in other areas of West Africa. We performed a cross-sectional, clinic-based study to investigate the presence of RF in Togo during 2002-2004. Blood samples from patients with fever were examined for RF spirochetes by microscopy, PCR, and DNA sequencing of amplicons and for antibodies to the glycerophosphodiester phosphodiesterase antigen. Although no spirochetes were seen in blood smears, approximately 10% of the patients were positive by PCR and approximately 13% were seropositive for spirochetes. DNA sequencing demonstrated that Borrelia crocidurae and B. duttonii were present. Most patients were treated for malaria whether or not plasmodia were observed. Thus, many RF patients originally had a misdiagnosis of malaria, which resulted in ineffective treatment. The inability of microscopic analysis to detect spirochetes compared with PCR demonstrates the need for tests with greater sensitivity.
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| 2. |
- Thein, Marcus, et al.
(författare)
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Oms38 is the first identified pore-forming protein in the outer membrane of relapsing fever spirochetes
- 2008
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Ingår i: Journal of Bacteriology. - 0021-9193 .- 1098-5530. ; 190:21, s. 7035-7042
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Tidskriftsartikel (refereegranskat)abstract
- Relapsing fever is a worldwide, endemic disease caused by several spirochetal species belonging to the genus Borrelia. During the recurring fever peaks, borreliae proliferate remarkably quickly compared to the slow dissemination of Lyme disease Borrelia and therefore require efficient nutrient uptake from the blood of their hosts. This study describes the identification and characterization of the first relapsing fever porin, which is present in the outer membranes of B. duttonii, B. hermsii, B. recurrentis, and B. turicatae. The pore-forming protein was purified by hydroxyapatite chromatography and designated Oms38, for outer membrane-spanning protein of 38 kDa. Biophysical characterization of Oms38 was done by using the black lipid bilayer method, demonstrating that Oms38 forms small, water-filled channels of 80 pS in 1 M KCl that did not exhibit voltage-dependent closure. The Oms38 channel is slightly selective for anions and shows a ratio of permeability for cations over anions of 0.41 in KCl. Analysis of the deduced amino acid sequences demonstrated that Oms38 contains an N-terminal signal sequence which is processed under in vivo conditions. Oms38 is highly conserved within the four studied relapsing fever species, sharing an overall amino acid identity of 58% and with a strong indication for the presence of amphipathic beta-sheets.
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