scholarly journals Generating Isogenic Deletions (Knockouts) in Francisella tularensis, a Highly-infectious and Fastidious Gram-negative Bacterium

BIO-PROTOCOL ◽  
2015 ◽  
Vol 5 (12) ◽  
Author(s):  
Xiaojun Wu ◽  
Guoping Ren ◽  
Jason Huntley
Keyword(s):  
Francisella Tularensis ◽  
Negative Bacterium ◽  
Gram Negative

scholarly journals Presence of Pili on the Surface of Francisella tularensis

2004 ◽  
Vol 72 (5) ◽  
pp. 3042-3047 ◽  
Author(s):  
Horacio Gil ◽  
Jorge L. Benach ◽  
David G. Thanassi
Keyword(s):  
Electron Microscopy ◽  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Live Vaccine ◽  
Live Vaccine Strain ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Schu S4 ◽  
Highly Virulent

ABSTRACT Francisella tularensis is a highly infectious gram-negative bacterium with potential for use as a bioweapon. Analysis of the F. tularensis live vaccine strain (LVS) ultrastructure by electron microscopy revealed the presence of long, thin fibers, similar in appearance to type 4 pili. The highly virulent F. tularensis Schu S4 strain was found to contain type 4 pilus genes, and we confirmed that these genes are present and expressed in the LVS.

scholarly journals Avidity of IgG class antibodies to Francisella tularensis in the course of tularemia in humans

2019 ◽  
pp. 43-50
Author(s):  
Waldemar Rastawicki ◽  
Karolina Śmietańska ◽  
Natalia Rokosz-Chudziak ◽  
Urszula Roguska
Keyword(s):  
Francisella Tularensis ◽  
Clinical Symptoms ◽  
Active Phase ◽  
Microbiological Diagnosis ◽  
Igg Antibodies ◽  
Negative Bacterium ◽  
Avidity Index ◽  
Serum Samples ◽  
Recent Infection ◽  
Gram Negative

Introduction: Tularemia is a highly infectious zoonotic disease caused by Gram-negative bacterium Francisella tularensis. The microbiological diagnosis of tularemia is based mainly on serological investigations. The present study was undertaken to determine the avidity of IgG class antibodies to Francisella tularensis in the course of tularemia in humans and to evaluate its value for estimation of the phase of diseases. Methods: Fifty two serum samples obtained from 40 patients with tularemia were tested by in-house ELISA in duplicate in the same plate, without and after the 0.5 h incubation with 8M urea. The age of the subjects was between 6 and 77 years. From one patient, a 9-years-old girl with oculoglandular form of tularemia, five serum samples were taken, respectively after 0.5, 1.5, 3, 6 and 12 months from the beginning of the first clinical symptoms. Results: The results of the study showed higher values of the avidity index (AI) of IgG antibodies for F. tularensis, often exceeding the value of 0.9, in children and adolescents than in adults. The examination of serum samples obtained 2-3 times in the course of tularemia from few patients did not show significant differences in the level of avidity index depending on the period of the disease. However, in five serum samples obtained from a 9-years-old girl in the different phases of tularemia the avidity index showed increasing values (0.51, 0.80, 0.92, 0.90 and 0.94, respectively). Conclusions: The avidity index of IgG may be helpful in excluding recent infection, but its usefulness in detecting an active phase of invasion requires further research.

scholarly journals Tularemia Goes West: Epidemiology of an Emerging Infection in Austria

2020 ◽  
Vol 8 (10) ◽  
pp. 1597 ◽  
Author(s):  
Stefanie Seiwald ◽  
Anja Simeon ◽  
Erwin Hofer ◽  
Günter Weiss ◽  
Rosa Bellmann-Weiler
Keyword(s):  
Infectious Disease ◽  
Differential Diagnosis ◽  
Francisella Tularensis ◽  
Clinical Manifestations ◽  
Zoonotic Disease ◽  
Public Institutions ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Potential Host ◽  
Emerging Infection

The zoonotic disease tularemia is caused by the Gram-negative bacterium Francisella tularensis, with the two major subspecies tularensis and holarctica being responsible for infections in humans and animals. The F. tularensis subspecies holarctica is less virulent and prevalent in Europe and Asia. Over the last few centuries, few epidemic outbreaks and low numbers of infections have been registered in the eastern part of Austria, specifically in the provinces of Lower Austria, Burgenland, and Styria. The reported infections were mostly associated with hunting hares and the skinning of carcasses. Within the last decade, ticks have been identified as important vectors in Tyrol and served as first evidence for the spread of F. tularensis to Western Austria. In 2018, the pathogen was detected in hares in the provinces of Tyrol, Vorarlberg, and Salzburg. We presume that F. tularensis is now established in most regions of Austria, and that the investigation of potential host and vector animals should be spotlighted by public institutions. Tularemia in humans presents with various clinical manifestations. As glandular, ulceroglandular, and typhoidal forms occur in Austria, this infectious disease should be considered as a differential diagnosis of unknown fever.

scholarly journals Francisella tularensisBacteremia: A Case Report from Sudan

2012 ◽  
Vol 2012 ◽  
pp. 1-2 ◽  
Author(s):  
Salma E. R. Mohamed ◽  
Aymun I. Mubarak ◽  
Lamia O. Alfarooq
Keyword(s):  
Lymph Nodes ◽  
Francisella Tularensis ◽  
Shortness Of Breath ◽  
Negative Bacterium ◽  
Blood Cell Count ◽  
Southern Sudan ◽  
Gram Negative ◽  
Empiric Antibiotic ◽  
Empiric Antibiotic Treatment ◽  
Highly Virulent

Francisella tularensisis a highly virulent intracellular gram-negative bacterium. The organism is usually isolated from wild and domestic animals and invertebrate. Man gets infection by direct contact with those animals or their products but the most common mode of transmission is via arthropod vectors. The disease is endemic in North America, parts of Europe, and Asia but has never been reported in Africa. A 29-year old male living in a rural area of Southern Sudan has been maintained on continuous ambulatory peritoneal dialysis for two years. He presented to our center in May 2010 complaining of fever, dry cough, shortness of breath, and abdominal discomfort for four days. He was very ill, pale, and dehydrated. There were enlarged tender submandibular lymph nodes, but no mouth ulcers or other palpable lymph nodes. Peritonitis was excluded by effluent white blood cell count and culture. Empiric antibiotic treatment with ceftriaxon, and ciprofloxacin was started. Gram-negative coccobacilli were isolated by blood culture. The organism was identified asFrancisella tularensis. We started him on a ten-day course of gentamicin after which he improved. This is, to the best of our knowledge, the first reported case of bacteremia caused byFrancisella tularensisin Sudan.

scholarly journals PCR based prevalence study of Francisella tularensis in Kharkiv, Dnipropetrovsk, and Mykolaiv oblasts during 2015–2018

2020 ◽  
Vol 64 (1) ◽  
pp. 63-71
Author(s):  
Oksana Borysivna Zlenko ◽  
Gennadiy Evgenievich Tkach ◽  
Anna Borysivna Sukhorukova ◽  
Lyudmila Vitaliivna Kylypko ◽  
Lubov Stepanivna Machota ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Genetic Material ◽  
Zoonotic Disease ◽  
Prevalence Study ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Field Samples ◽  
Positive Results ◽  
Owl Pellets

AbstractIntroductionTularaemia is a zoonotic disease caused by the gram-negative bacterium Francisella tularensis, which is endemic to Ukraine. The aim of this work was to provide screening of different field samples (rodent tails, ticks, pellets, water, and hay) to obtain an actual picture of the tularaemia epizootic situation in the Kharkiv, Dnipropetrovsk, and Mykolaiv oblasts.Material and MethodsSamples were collected using the flag method (for ticks) and break-back traps (for rodents). Also, hay, water and owl pellets were collected for study. The F. tularensis genetic material in samples was detected using a 16S qPCR.ResultsIt was found that in Kharkiv oblast, 23% of collected samples were positive for F. tularensis, in Dnipropetrovsk oblast 1.9%, and in Mykolaiv oblast 0.4%.ConclusionAmong the sample types, 34.7% of ticks, 1.8% of rodents, and 36.4% of pellets were positive for F. tularensis. The most frequent carriers of F. tularensis were the D. reticulatus and I. ricinus ticks (74.2% and 29.3%, respectively, of positive results).

scholarly journals Alternative mechanisms of ribosome stalling rescue in the gram‐negative bacterium Francisella tularensis

2019 ◽  
Vol 33 (S1) ◽  
Author(s):  
Pooja Srinivas ◽  
Tyler D. P. Goralski ◽  
Kenneth C. Keiler ◽  
Christine M. Dunham
Keyword(s):  
Francisella Tularensis ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Ribosome Stalling

scholarly journals Massiliamide, a cyclic tetrapeptide with potent tyrosinase inhibitory properties from the Gram-negative bacterium Massilia albidiflava DSM 17472T

2020 ◽  
Author(s):  
Andri Frediansyah ◽  
Jan Straetener ◽  
Heike Brötz-Oesterhelt ◽  
Harald Gross
Keyword(s):  
Absolute Configuration ◽  
Inhibitory Activity ◽  
Liquid Culture ◽  
Spectroscopic Analysis ◽  
2D Nmr ◽  
Negative Bacterium ◽  
Gram Negative ◽  
The Absolute ◽  
Potent Inhibitory Activity ◽  
Cyclic Tetrapeptide

AbstractA cyclic tetrapeptide, designated massiliamide, was isolated from the liquid culture of the Gram-negative bacterium Massilia albidiflava DSM 17472T. The structure was elucidated through extensive spectroscopic analysis, including HR-MS and 1D and 2D NMR experiments. The absolute configuration was determined using the Marfey´s method. Massiliamide showed potent inhibitory activity towards tyrosinase with an IC50 value of 1.15 µM and no cytotoxicity.

scholarly journals Porphyromonas gingivalis fimbrial protein Mfa5 contains a von Willebrand factor domain and an intramolecular isopeptide

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Thomas V. Heidler ◽  
Karin Ernits ◽  
Agnieszka Ziolkowska ◽  
Rolf Claesson ◽  
Karina Persson
Keyword(s):  
Porphyromonas Gingivalis ◽  
Von Willebrand Factor ◽  
Host Cells ◽  
Negative Bacterium ◽  
Oral Biofilm ◽  
Gram Negative ◽  
Type V ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Fimbrial Protein

AbstractThe Gram-negative bacterium Porphyromonas gingivalis is a secondary colonizer of the oral biofilm and is involved in the onset and progression of periodontitis. Its fimbriae, of type-V, are important for attachment to other microorganisms in the biofilm and for adhesion to host cells. The fimbriae are assembled from five proteins encoded by the mfa1 operon, of which Mfa5 is one of the ancillary tip proteins. Here we report the X-ray structure of the N-terminal half of Mfa5, which reveals a von Willebrand factor domain and two IgG-like domains. One of the IgG-like domains is stabilized by an intramolecular isopeptide bond, which is the first such bond observed in a Gram-negative bacterium. These features make Mfa5 structurally more related to streptococcal adhesins than to the other P. gingivalis Mfa proteins. The structure reported here indicates that horizontal gene transfer has occurred among the bacteria within the oral biofilm.

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