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The Journal of Infectious Diseases Advance Access, 23.11.2019
Tilføjet 25.11.2019 05:14
A novel laminin-binding protein mediates microbial-endothelial cell interactions and facilitates dissemination of Lyme disease pathogens
AbstractBorrelia burgdorferi conserved gene-products BB0406 and BB0405, members of a common B. burgdorferi paralogous gene family, share 59% similarity. While both gene-products can function as potential porins, only BB0405 is essential for infection. Here we show that, despite sequence homology and co-expression from the same operon, both proteins differ in their membrane localization attributes, antibody accessibility, and immunogenicity in mice. BB0406 is required for spirochete survival in mammalian hosts, particularly for the disseminated infection in distant organs. We identified that BB0406 interacts with laminin, one of the major constituents of the vascular basement membrane, and facilitates spirochete transmigration across host endothelial cell barriers. A better understanding of how B. burgdorferi transmigrates through dermal and tissue vascular barriers and establishes disseminated infections will contribute to the development of novel therapeutics to combat early infection.
Latest Results for Infection, 14.09.2019
Tilføjet 16.09.2019 09:02
Assessment of Coxiella burnetii presence after tick bite in north-eastern Poland
The aim of the study is to assess anti-Coxiella burnetii antibodies presence in inhabitants of north-eastern Poland, to assess the risk of Q fever after tick bite and to assess the percentage of co-infection with other pathogens.
The serological study included 164 foresters and farmers with a history of tick bite. The molecular study included 540 patients, hospitalized because of various symptoms after tick bite. The control group consisted of 20 honorary blood donors. Anti-Coxiella burnetii antibodies titers were determined by Coxiella burnetii (Q fever) Phase 1 IgG ELISA (DRG International Inc. USA). PCR was performed to detect DNA of C. burnetii, Borrelia burgdorferi and Anaplasma phagocytophilum.
Anti-C. burnetii IgG was detected in six foresters (7.3%). All foresters with the anti-C. burnetii IgG presence were positive toward anti-B. burgdorferi IgG and anti-TBE (tick-borne encephalitis). Anti-C. burnetii IgG was detected in five farmers (6%). Four farmers with anti-C. burnetii IgG presence were positive toward anti-B. burgdorferi IgG and two with anti-TBE. Among them one was co-infected with B. burgdorferi and TBEV. Correlations between anti-C. burnetii IgG and anti-B. burgdorferi IgG presence and between anti-C. burnetii IgG presence and symptoms of Lyme disease were observed. C. burnetii DNA was not detected in any of the 540 (0%) patients.
C. burnetii is rarely transmitted by ticks, but we proved that it is present in the environment, so it may be a danger to humans. The most common co-occurrence after tick bite concerns C. burnetii and B. burgdorferi.
Clinical Microbiology and Infection,
Tilføjet 10.08.2019 00:43
Borrelia miyamotoi infection leads to cross-reactive antibodies to the C6 peptide in mice and men
Borrelia miyamotoi is a relapsing fever Borrelia, transmitted by hard (Ixodes) ticks, which are also the main vector for Borrelia burgdorferi. A widely used test for serodiagnosis of Lyme borreliosis is an EIA based on the C6 peptide of the B. burgdorferi sl VlsE protein. We set out to study C6 reactivity upon infection with B. miyamotoi in a large well-characterized set of Borrelia miyamotoi disease (BMD) patient sera and in experimental murine infection.
IAI Accepts: Articles Published Ahead of Print, 13.05.2019
Tilføjet 19.05.2019 19:48
Delineating surface epitopes of Lyme disease pathogen targeted by highly protective antibodies of New Zealand White rabbits [Microbial Immunity and Vaccines]
Lyme disease (LD), the most prevalent vector-borne illness in the United States and Europe, is caused by Borreliella burgdorferi (Bb). No vaccine is available for humans. Dogmatically, Bb can establish a persistent infection in the mammalian host (e.g., mice) due to a surface antigen, VlsE. This antigenically variable protein allows the spirochete to continually evade borreliacidal antibodies. However, our recent study has shown that the Bb spirochete is effectively cleared by anti-Bb antibodies of New Zealand White rabbits despite the surface expression of VlsE. Besides homologous protection, the rabbit antibodies also cross-protect against heterologous Bb and significantly reduced pathology of LD arthritis in persistently infected mice. Thus, this finding that NZW rabbits develop a unique repertoire of very potent antibodies targeting the protective surface epitopes, despite abundant VlsE, prompted us to identify specificities of the rabbit protective antibodies and their respective targets. By applying subtractive reverse vaccinology, which involved random peptide phage display libraries coupled with the next generation sequencing and our computational algorithms, repertoires of non-protective (early) and protective (late) rabbit antibodies were identified and directly compared. Consequently, putative surface epitopes that are unique to the rabbit protective sera have been mapped. Importantly, the relevance of newly identified protection-associated epitopes for their surface exposure has been strongly supported by prior empirical studies. This study is significant because it now allows us to systematically test the putative epitopes for their protective efficacy with an ultimate goal of selecting the most efficacious targets for development of a long-awaited LD vaccine.
The American Journal of Tropical Medicine and Hygiene: Most Recent Articles, 4.12.2019
Tilføjet 05.12.2019 14:40
Host Competency of the Multimammate Rat Mastomys natalensis Demonstrated by Prolonged Spirochetemias with the African Relapsing Fever Spirochete Borrelia crocidurae
African multimammate rats, Mastomys natalensis, are widely distributed in sub-Saharan Africa and live in close association with humans. In West Africa, numerous field studies have shown these animals may be naturally infected with the relapsing fever spirochete Borrelia crocidurae, the primary cause of tick-borne relapsing fever in this region of the continent. However, naturally infected individual rats have never been examined over time; therefore, the true host competency of these rats for this spirochete is unknown. Therefore, using animals from an established laboratory colony of M. natalensis, rats were experimentally infected with B. crocidurae and their blood examined to 28 days postinoculation. These animals were highly susceptible to infection and displayed prolonged and cyclic spirochetemias. Our results demonstrate these peridomestic rodents are likely competent hosts for infecting argasid tick vectors and play a primary role in the enzootic cycle for B. crocidurae in West Africa.
AAC Accepts: Articles Published Ahead of Print, 29.04.2019
Tilføjet 30.04.2019 11:40
Molecular testing of serial blood specimens from patients with early Lyme disease during treatment reveals changing co-infection with mixtures of Borrelia burgdorferi genotypes. [Clinical Therapeutics]
Borrelia burgdorferi is the etiological agent of Lyme disease. In the current study, we used direct detection PCR and electrospray ionization mass spectrometry to monitor and genotype B. burgdorferi from serially collected whole blood specimens from clinically diagnosed early Lyme disease patients before and during 21 days of antibiotic therapy. B. burgdorferi was detected up to three weeks after the initiation of antibiotic treatment with ratios of co-infecting B. burgdorferi genotypes changing over time.
Clinical Infectious Diseases Advance Access, 17.10.2019
Tilføjet 17.10.2019 11:53
Protective Immunity and New Vaccines for Lyme Disease
AbstractLyme disease, caused by some Borrelia burgdorferi sensu lato, is the most common tick-borne illness in the Northern Hemisphere and the number of cases, and geographic spread, continue to grow. Previously identified B. burgdorferi proteins, lipid immunogens, and live mutants lead the design of canonical vaccines aimed at disrupting infection in the host. Discovery of the mechanism of action of the first vaccine catalyzed the development of new strategies to control Lyme disease that bypassed direct vaccination of the human host. Thus, novel prevention concepts center on proteins produced by B. burgdorferi during tick transit and on tick proteins that mediate feeding and pathogen transmission. A burgeoning area of research is tick immunity as it can unlock mechanistic pathways that could be targeted for disruption. Studies that shed light on the mammalian immune pathways engaged during tick-transmitted B. burgdorferi infection would further development of vaccination strategies against Lyme disease.
The American Journal of Tropical Medicine and Hygiene: Most Recent Articles, 5.06.2019
Tilføjet 06.06.2019 10:30
Testing the Competence of Cimex lectularius Bed Bugs for the Transmission of Borrelia recurrentis, the Agent of Relapsing Fever
In recent years, bed bugs have reappeared in greater numbers, more frequently, and are biting humans in many new geographic areas. Infestations by these hematophagous insects are rapidly increasing worldwide. Borrelia recurrentis, a spirochete bacterium, is the etiologic agent of louse-borne relapsing fever. The known vectors are body lice, Pediculus humanus humanus. However, previous studies have suggested that bed bugs might also be able to transmit this bacterium. Adult Cimex lectularius were artificially infected with a blood meal mixed with bacterial suspension of B. recurrentis. They were subsequently fed with pathogen-free human blood until the end of the experiment. Bed bugs and feces were collected every 5 days to evaluate the capacity of bed bugs to acquire and excrete viable B. recurrentis using molecular biology, cultures, fluorescein diacetate and immunofluorescence assays. The feces collected on the day 5 and 10 postinfection contained viable bacteria. Immunofluorescence analysis of exposed bed bugs showed the presence of B. recurrentis in the digestive tract, even in bed bugs collected on day 20 after infection. Like human body lice, bed bugs can acquire, maintain, and excrete viable B. recurrentis that might infect humans through skin lesions. This preliminary work suggests that bed bugs might be competent vectors of B. recurrentis. Because bed bugs and body lice may share the same ecological niches, the role of bed bugs in transmitting recurrent fevers deserves further study.
IAI Accepts: Articles Published Ahead of Print,
Tilføjet 16.07.2019 08:35
The Generality of Post-Antimicrobial Treatment Persistence of Borrelia burgdorferi Strains N40 and B31 in Genetically Susceptible and Resistant Mouse Strains [Bacterial Infections]
A basic feature of infection caused by Borrelia burgdorferi, the etiological agent of Lyme borreliosis, is that persistent infection is the rule in its many hosts. The ability to persist and evade host immune clearance poses a challenge to effective antimicrobial treatment. A link between therapy failure and the presence of persister cells has started to emerge. There is growing experimental evidence that viable, but non-cultivable spirochetes persist following treatment with several different antimicrobial agents. The current study utilized the mouse model to evaluate if persistence occurs following antimicrobial treatment in a disease-susceptible (C3H/HeJ) and disease-resistant (C57BL/6) mouse strain infected with B. burgdorferi strains N40 and B31, to confirm the generality of this phenomena as well as to assess the persisters' clinical relevance. The status of infection was evaluated at 12 and 18-months after treatment. The results demonstrated that persistent spirochetes remain viable for up to 18 months following treatment, as well as being non-cultivable. The phenomenon of persistence in disease-susceptible C3H mice is equally evident in disease-resistant B6 mice, and not unique to any particular B. burgdorferi strain. Results also demonstrate that following antimicrobial treatment, both strains of B. burgdorferi, N40 and B31, lose one or more plasmids. The study demonstrated that non-cultivable spirochetes can persist in a host following antimicrobial treatment for a long time but did not demonstrate their clinical relevance in a mouse model of chronic infection. The clinical relevance of persistent spirochetes beyond 18 months following antimicrobial treatment require further studies in other animal models.
Emerging Infectious Diseases Journal, 30.08.2019
Tilføjet 16.09.2019 09:02
Two Cases of Borrelia miyamotoi Meningitis, Sweden, 2018
Clinical Microbiology and Infection,
Tilføjet 13.07.2019 04:01
Unconventional diagnostic tests for Lyme borreliosis: a systematic review
Lyme borreliosis (LB) diagnosis currently relies mainly on serological tests and sometimes polymerase chain reaction or culture. However, other biological assays are being developed to try to improve Borrelia-infection diagnosis and/or monitoring.
Latest Results for BMC Infectious Diseases, 20.08.2019
Tilføjet 20.08.2019 15:59
Validation of cellular tests for Lyme borreliosis (VICTORY) study
Lyme borreliosis (LB) is a tick-borne disease caused by spirochetes belonging to the Borrelia burgdorferi sensu lato species. Due to a variety of clinical manifestations, diagnosing LB can be challenging, and laboratory work-up is usually required in case of disseminated LB. However, the current standard of diagnostics is serology, which comes with several shortcomings. Antibody formation may be absent in the early phase of the disease, and once IgG-seroconversion has occurred, it can be difficult to distinguish between a past (cured or self-cleared) LB and an active infection. It has been postulated that novel cellular tests for LB may have both higher sensitivity earlier in the course of the disease, and may be able to discriminate between a past and active infection.
VICTORY is a prospective two-gate case-control study. We strive to include 150 patients who meet the European case definitions for either localized or disseminated LB. In addition, we aim to include 225 healthy controls without current LB and 60 controls with potentially cross-reactive conditions. We will perform four different cellular tests in all of these participants, which will allow us to determine sensitivity and specificity. In LB patients, we will repeat cellular tests at 6 weeks and 12 weeks after start of antibiotic treatment to assess the usefulness as ‘test-of-cure’. Furthermore, we will investigate the performance of the different cellular tests in a cohort of patients with persistent symptoms attributed to LB.
This article describes the background and design of the VICTORY study protocol. The findings of our study will help to better appreciate the utility of cellular tests in the diagnosis of Lyme borreliosis.
NL7732 (Netherlands Trial Register, trialregister.nl).