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Daniel L Clemens, Bai-Yu Lee, Marcus A Horwitz
Francisella tularensisis subsp. tularensis is an intracellular bacterial pathogen and the causative agent of the life-threatening zoonotic disease tularemia. The Francisella Pathogenicity Island encodes a large secretion apparatus, known as a Type VI Secretion System (T6SS), which is essential for Francisella to escape from its phagosome and multiply within host macrophages and to cause disease in animals. The T6SS, found in one-quarter of Gram-negative bacteria including many highly pathogenic ones, is a recently discovered secretion system that is not yet fully understood...
2018: Frontiers in Cellular and Infection Microbiology
Qingmei Jia, Richard Bowen, Barbara Jane Dillon, Saša Masleša-Galić, Brennan T Chang, Austin C Kaidi, Marcus A Horwitz
Bacillus anthracis, Yersinia pestis, and Francisella tularensis are the causative agents of Tier 1 Select Agents anthrax, plague, and tularemia, respectively. Currently, there are no licensed vaccines against plague and tularemia and the licensed anthrax vaccine is suboptimal. Here we report F. tularensis LVS ΔcapB (Live Vaccine Strain with a deletion in capB)- and attenuated multi-deletional Listeria monocytogenes (Lm)-vectored vaccines against all three aforementioned pathogens. We show that LVS ΔcapB- and Lm-vectored vaccines express recombinant B...
May 3, 2018: Scientific Reports
Guolin Cui, Jun Wang, Xinyi Qi, Jingliang Su
Francisella tularensis is a facultative intracellular Gram-negative bacterium that causes the zoonotic disease tularemia. We identified the transcription elongation factor GreA as a virulence factor in our previous study, but its role was not defined. Here, we investigate the effects of the inactivation of the greA gene, generating a greA mutant of F. tularensis subsp. novicida. Inactivation of greA impaired the bacterial invasion into and growth within host cells, and subsequently virulence in mouse infection model...
May 2, 2018: Scientific Reports
Gete Hestvik, Henrik Uhlhorn, Roland Mattsson, Eva Westergren, Fredrik Södersten, Sara Åkerström, Dolores Gavier-Widén
BACKGROUND: Tularemia is a zoonosis caused by the bacterium Francisella tularensis. It has a wide host range, which includes mammals, birds and invertebrates. F. tularensis has often been isolated from various species of small rodents, but the pathology in naturally infected wild rodent species has rarely been reported. CASE PRESENTATION: Herein, we describe the pathology of tularemia in two naturally infected wild yellow-necked mice (Apodemus flavicollis). To visualize F...
May 2, 2018: Acta Veterinaria Scandinavica
F Drago, Sanja Javor, Aurora Parodi
Tularemia is an infectious zoonosis caused by Francisella tularensis , an aerobic, noncapsulated, Gram-negative coccobacillus. It is more common in the northern hemisphere, and there are sporadic reports in nonendemic areas. The bacterium is usually transmitted by the bite or feces of a tick or other arthropods such as mosquitoes and horseflies. We report a case of an Italian patient with tularemia after a horsefly bite.
April 30, 2018: American Journal of Tropical Medicine and Hygiene
Gowribidanur C Pavithra, Udupi A Ramagopal
Francisella tularensis is classified as a category A bioterrorism agent, which also causes tularemia. Here, we present the crystal structure of apo and adenine bound form of the adenine phosphoribosyltransferase (APRT) from Francisella tularensis.. APRT is an enzyme involved in the salvage of adenine (a 6-aminopurine) to adenosine monophosphate (AMP). The purine salvage pathway relies on two essential and distinct enzymes to convert 6-aminopurine and 6-oxopurines into corresponding nucleotides. The mechanism by which these enzymes differentiate different purines is not clearly understood...
April 25, 2018: FEBS Journal
Gene McClellan, Margaret Coleman, David Crary, Alec Thurman, Brandolyn Thran
Military health risk assessors, medical planners, operational planners, and defense system developers require knowledge of human responses to doses of biothreat agents to support force health protection and chemical, biological, radiological, nuclear (CBRN) defense missions. This article reviews extensive data from 118 human volunteers administered aerosols of the bacterial agent Francisella tularensis, strain Schu S4, which causes tularemia. The data set includes incidence of early-phase febrile illness following administration of well-characterized inhaled doses of F...
April 25, 2018: Risk Analysis: An Official Publication of the Society for Risk Analysis
Rupin Kumar, Mohamed Mansour, Jacqueline Brunetto, Renuka Verma, Margaret Fisher, Jonathan Teitelbaum
We report an 18-month-old male who presented with fever and nonspecific symptoms. He was evaluated for multiple differential diagnoses including Kawasaki disease and JIA and received treatment for them. After he was readmitted, tularemia was considered based on the physical exam finding of an ulcer on the scalp and enlarged lymph nodes. Tularemia titers were positive, and the patient was given the appropriate antibiotic and was discharged home. Follow-up of the patient showed complete resolution of symptoms...
2018: Case Reports in Pediatrics
Alison A McCormick, Aisha Shakeel, Chris Yi, Hardeep Kaur, Ahd M Mansour, Chandra Shekhar Bakshi
Tularemia is a fatal human disease caused by Francisella tularensis, a Gram-negative encapsulated coccobacillus bacterium. Due to its low infectious dose, ease of aerosolized transmission, and lethal effects, the CDC lists F. tularensis as a Category A pathogen, the highest level for a potential biothreat agent. Previous vaccine studies have been conducted with live attenuated, inactivated, and subunit vaccines, which have achieved partial or full protection from F. tularensis live vaccine strain (LVS) challenge, but no vaccine has been approved for human use...
2018: PloS One
Lydia M Roberts, Daniel A Powell, Jeffrey A Frelinger
Francisella tularensis is an intracellular bacterium that causes the disease tularemia. There are several subspecies of F. tularensis whose ability to cause disease varies in humans. The most virulent subspecies, tularensis , is a Tier One Select Agent and a potential bioweapon. Although considerable effort has made to generate efficacious tularemia vaccines, to date none have been licensed for use in the United States. Despite the lack of a tularemia vaccine, we have learned a great deal about the adaptive immune response the underlies protective immunity...
2018: Frontiers in Cellular and Infection Microbiology
Tina Guina, Lynda L Lanning, Kristian S Omland, Mark S Williams, Larry A Wolfraim, Stephen P Heyse, Christopher R Houchens, Patrick Sanz, Judith A Hewitt
Francisella tularensis is a highly infectious Gram-negative bacterium that is the etiologic agent of tularemia in animals and humans and a Tier 1 select agent. The natural incidence of pneumonic tularemia worldwide is very low; therefore, it is not feasible to conduct clinical efficacy testing of tularemia medical countermeasures (MCM) in human populations. Development and licensure of tularemia therapeutics and vaccines need to occur under the Food and Drug Administration's (FDA's) Animal Rule under which efficacy studies are conducted in well-characterized animal models that reflect the pathophysiology of human disease...
2018: Frontiers in Cellular and Infection Microbiology
Joshua R Fletcher, Deborah D Crane, Tara D Wehrly, Craig A Martens, Catharine M Bosio, Bradley D Jones
Francisella tularensis is a highly infectious bacterial pathogen that causes the potentially fatal disease tularemia. The Live Vaccine Strain (LVS) of F. tularensis subsp. holarctica , while no longer licensed as a vaccine, is used as a model organism for identifying correlates of immunity and bacterial factors that mediate a productive immune response against F. tularensis . Recently, it was reported that two biovars of LVS differed in their virulence and vaccine efficacy. Genetic analysis showed that they differ in ferrous iron homeostasis; lower Fe2+ levels contributed to increased resistance to hydrogen peroxide in the vaccine efficacious LVS biovar...
2018: Frontiers in Microbiology
Kemalettin Özden, Ayşe Özden, Ayşe Albayrak, Zülal Özkurt, Hakan Döneray, Mehmet Parlak
Tularemia is a zoonotic infectious disease caused by Francisella tularensis. Tularemia is endemic in the northern hemisphere and is usually seen in North America, Europe and Asia. Although the ulceroglandular tularemia is the most common form in these regions, the oropharyngeal form is more prevalent in Eastern Europe, including Turkey. The disease has importance in Turkey due to its wide geographic distribution and periodic outbreaks. The aim of this study was to determine the demographic, clinical and epidemiological characteristics of oropharyngeal tularemia patients...
January 2018: Mikrobiyoloji Bülteni
Matthias Wittwer, Ekkehard Altpeter, Paola Pilo, Sebastian M Gygli, Christian Beuret, Frederic Foucault, Rahel Ackermann-Gäumann, Urs Karrer, Daniela Jacob, Roland Grunow, Nadia Schürch
Whole genome sequencing (WGS) methods provide new possibilities in the field of molecular epidemiology. This is particularly true for monomorphic organisms where the discriminatory power of traditional methods (e.g., restriction enzyme length polymorphism typing, multi locus sequence typing etc.) is inadequate to elucidate complex disease transmission patterns, as well as resolving the phylogeny at high resolution on a micro-geographic scale. In this study, we present insights into the population structure of Francisella tularensis subsp...
2018: Frontiers in Cellular and Infection Microbiology
Tomasz Chmielewski, Beata Fiecek, Grażyna Lewandowska, Waldemar Rastawicki, Stanisława Tylewska-Wierzbanowska
Introduction: Tularemia and spotted fever group rickettsioses (SFG) can be transmitted by ticks and have a number of common clinical symptoms. Most characteristic are a maculopapular or vesicular rash or an eschar at the site of the tick or insect bite accompanied by painful lymph nodes. The aim of this study was to determine whether Rickettsia spp./ Francisella tularensis mixed infections occurred in patients with similar symptoms who were diagnosed with either Rickettsia spp. or F. tularensis infection...
March 2018: Archives of Medical Science: AMS
Anne Busch, Prasad Thomas, Eric Zuchantke, Holger Brendebach, Kerstin Neubert, Josephine Gruetzke, Sascha Al Dahouk, Martin Peters, Helmut Hotzel, Heinrich Neubauer, Herbert Tomaso
Francisella ( F. ) tularensis is a highly virulent, Gram-negative bacterial pathogen and the causative agent of the zoonotic disease tularemia. Here, we generated, analyzed and characterized a high quality circular genome sequence of the F. tularensis subsp. holarctica strain 12T0050 that caused fatal tularemia in a hare. Besides the genomic structure, we focused on the analysis of oriC, unique to the Francisella genus and regulating replication in and outside hosts and the first report on genomic DNA methylation of a Francisella strain...
2018: Frontiers in Microbiology
Sarah J Coates, Benjamin Briggs, Kelly M Cordoro
Tularemia is a rare and potentially life-threatening infection caused by the highly infectious gram-negative coccobacillus Francisella tularensis. We present the case of an 11-year old girl who presented with erythema multiforme minor in the setting of an indolent but progressive soft tissue infection and was found to have tularemia. We review the role of dermatologists in identifying the features of and complications associated with this rare zoonosis and discuss the potential effect of climate change on its incidence...
March 26, 2018: Pediatric Dermatology
Arzu Karlı, Gülnar Şensoy, Şule Paksu, Muhammet Furkan Korkmaz, Ömer Ertuğrul, Rıfat Karlı
Purpose: Tularemia is an infection caused by Francisella tularensis . Its diagnosis and treatment may be difficult in many cases. The aim of this study was to evaluate treatment modalities for pediatric tularemia patients who do not respond to medical treatment. Methods: A single-center, retrospective study was performed. A total of 19 children with oropharyngeal tularemia were included. Results: Before diagnosis, the duration of symptoms in patients was 32...
February 2018: Korean Journal of Pediatrics
Alexander B Hicks, Dirk M Elston
Dermacentor ticks are hard ticks found throughout most of North America and are easily identified by their large size, ornate scutum, and prominent dorsal pits. They are important disease vectors and are implicated in transmission of Rocky Mountain spotted fever (RMSF), Colorado tick fever, tularemia, and erlichiosis. They also are an important cause of fatal tick paralysis.
January 2018: Cutis; Cutaneous Medicine for the Practitioner
F Ehrensperger, L Riederer, A Friedl
A female jogger was attacked by a common buzzard (Buteo buteo) and was scratched lightly at the back of the head. One week later she was taken ill with high fever and headache which was later diagnosed as ulcero-glandular tularemia in regional lymph nodes, caused by Francisella tularensis. Recovery was only achieved after several weeks of systemic antibiotic treatment (Gentamicin/ Ciprofloxacine). Tularemia is a well known zoonotic disease, called "rabbit fever", mainly affecting rabbits and hares, but also small rodents...
March 2018: Schweizer Archiv Für Tierheilkunde
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