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Objective To compare the pattern of antibody responses to Borrelia burgdorferi in patients with antibiotic-refractory, antibiotic-responsive, or non–antibiotic-treated Lyme arthritis as an indirect measure of spirochetal persistence or eradication. Methods At least 3 serial serum samples from 41 patients with antibiotic-refractory arthritis and 23 patients with antibiotic-responsive arthritis, and samples from 10 non–antibiotic-treated, historical control patients were tested for IgG reactivity with B burgdorferi sonicate and 4 differentially expressed outer surface lipoproteins of the spirochete, by enzyme-linked immunosorbent assay. Results Among non–antibiotic-treated patients, antibody titers to B burgdorferi antigens remained high throughout a 2–5-year period of arthritis. In contrast, in patients with antibiotic-responsive arthritis, in whom joint swelling usually resolved during a 1-month course of oral antibiotic therapy, the median antibody titers to most of the spirochetal antigens remained steady or decreased during the first 1–3 months after starting antibiotic therapy. In patients with antibiotic-refractory arthritis, who had persistent joint swelling for a median duration of 10 months despite 2–3 months of oral or intravenous antibiotics, the median titers to most antigens increased slightly during the first 1–3 months. However, by 4–6 months after starting antibiotic therapy, reactivity with all antigens declined similarly in both antibiotic-treated groups. Conclusion Whereas the antibody titers to B burgdorferi remained high in non–antibiotic-treated patients, the titers declined similarly 4–6 months after starting therapy in patients with antibiotic-responsive or antibiotic-refractory arthritis, suggesting that synovial inflammation persisted in patients with antibiotic-refractory arthritis after the period of infection.

DNA was extracted from pools of Amblyomma americanum ticks collected from vegetation at two sites in Fort Leonard Wood, Missouri and tested for the presence of Borrelia spp. Two new methods were developed to detect Borrelia lonestari DNA by targeting the glycerophosphodiester phosphodiesterase (glpQ) gene. The first method detected B. lonestari DNA using a SYBR green I melting curve analysis of the PCR product obtained with glpQ gene primers. The second method, a glpQ TaqMan assay, detected and confirmed the presence of B. lonestari glpQ-specific sequences. Twenty-two of 95 tick pools collected at site A148 contained B. lonestari DNA. None of 19 pools from site A241 contained B. lonestari DNA. No B. burgdorferi sensu lato DNA was detected using a SYBR green I melting curve analysis of the PCR product obtained with outer surface protein A (ospA) primers. The overall B. lonestari infection prevalence (with 95% confidence interval) at site A148 was estimated using two algorithms: minimum infection rate 4.14% (2.45, 5.84) and maximum likelihood with correction 4.82% (3.11, 7.16). The merits of each are discussed. Sequencing of the entire B. lonestari glpQ and partial 16S rRNA genes revealed two genetic variants circulating in this population of A. americanum from Missouri.

In a study of US patients with Lyme disease, immunoglobulin (Ig) G and IgM antibody responses to recombinant Borrelia burgdorferi antigen VlsE1 (rVlsE1), IgG responses to a synthetic peptide homologous to a conserved internal sequence of VlsE (C6), and IgM responses to a synthetic peptide comprising the C-terminal 10 amino acid residues of a B. burgdorferi outer-surface protein C (pepC10) were evaluated by kinetic enzyme-linked immunoassay. At 99% specificity, the overall sensitivities for detecting IgG antibody to rVlsE1 or C6 in samples from patients with diverse manifestations of Lyme disease were equivalent to that of 2-tiered testing. When data were considered in parallel, 2 combinations (IgG responses to either rVlsE1 or C6 in parallel with IgM responses to pepC10) maintained high specificity (98%) and were significantly more sensitive than 2-tiered analysis in detecting antibodies to B. burgdorferi in patients with acute erythema migrans. In later stages of Lyme disease, the sensitivities of the in parallel tests and 2-tiered testing were high and statistically equivalent

A glpQ ortholog was identified in DNA from Borrelia lonestari- positive Amblyomma americanum , providing further evidence that B. lonestari is more closely related to the relapsing fever group spirochetes than to borreliae that cause Lyme disease. This finding provides a basis for developing diagnostic assays to differentiate species of borrelia transmitted by hard ticks.

Amblyomma americanum collected near Lake Wappapello, Missouri, tested positive for Borrelia lonestari using polymerase chain reaction and sequence analyses of B. lonestari 16S rRNA and flagellin (flaB) genes. Twelve pools containing a total of 214 nymph or adult ticks contained evidence of infection with B. lonestari (minimum prevalence 5.6%). These data suggest that persons in southeast Missouri are at risk for exposure to B. lonestari after A. americanum tick bite, a possible cause of erythema migrans-like rash illness in this region. Derivation of the complete coding sequence for B. lonestari flaB is also reported.

Francisella tularensis, the causative agent of tularemia, is a highly infectious pathogen of humans and animals, yet little is known about the surface proteins of this organism that mediate mechanisms of pathogenicity. lTnphoA was used to generate random alkaline phosphatase gene fusions in a F. tularensis subsp. tularensis (strain Schu S4) genomic library to identify genes encoding exported extracytoplasmic proteins. Eleven genes encoding membrane-associated proteins were identified by this method and their respective signal peptides were characterized. Three of the genes encoded conserved ‘housekeeping’ enzymes, while the other eight genes were unique to F. tularensis, encoding proteins with molecular masses ranging from 11 to 78 kDa as deduced from the amino acid sequences. Two genes putatively encoded lipoproteins based on the presence of characteristic signal peptidase II cleavage sites. Four selected proteins were found associated with outer membranes from Schu S4 and LVS strains by Western blotting. Indirect immunofluorescence of strain Schu S4 cells also showed evidence of protein localization to the outer membrane. Protein database searches produced significant alignments with proteins from other bacteria involved in carbohydrate transport, lipid metabolism, and cell envelope biogenesis, thereby providing clues for putative functions. These findings demonstrated that TnphoA mutagenesis can be used in conjunction with F. tularensis genome sequence data to provide a foundation for studies to identify and define cellular surface protein virulence factors of this pathogen. Published by Elsevier Ltd.

A one-inoculation regimen of recombinant outer-surface protein C (OspC), which has been demonstrated to elicit protective immunity against a tick-borne challenge of Borrelia burgdorferi, was administered to outbred mice. Following seroconversion, the serum antibody titre against OspC was allowed to wane with time until there was little or no detection of anti-OspC antibodies by immunoblot. The mice were then challenged with an infectious dose of B. burgdorferi by tick transmission. Eleven of 12 OspC-primed mice subsequently became infected by B. burgdorferi, demonstrating that a protective anamnestic response was not generated in these mice following the introduction of infectious OspC-expressing spirochaetes.