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Spörndly‐Nees E, Grandi G, Thorsson E, Gustafsson TN, Omazic A. An Emerging Role for Ticks as Vectors of Tularaemia in Sweden. Vet Med Sci 2025; 11:e70094. [PMID: 39601264 PMCID: PMC11600208 DOI: 10.1002/vms3.70094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2024] [Revised: 09/24/2024] [Accepted: 10/11/2024] [Indexed: 11/29/2024] Open
Abstract
BACKGROUND The zoonotic bacterium Francisella tularensis, the causative agent of tularaemia, can be transmitted to humans via multiple routes, including through contact with infected animals, contaminated water or arthropod vectors. Ticks have not previously been described as transmitting the disease in Sweden. Recently, Ixodid tick species have expanded their latitudinal and altitudinal range in Sweden to areas where the disease is endemic. Tularaemia is a cause of growing concern, spreading to new areas in Sweden and infecting hares and humans. OBJECTIVES To establish whether ticks could be a potential arthropod vector in the transmission of F. tularensis subsp. holarctica in Sweden. METHODS Ticks were collected from northern Sweden and screened for F. tularensis. A follow-up study with ticks collected from F. tularensis-positive hares was performed. Ticks were analysed using real-time PCR and a pathological examination was performed on the hares. RESULTS F. tularensis subsp. holarctica was identified in ticks from one cat and three F. tularensis-infected hares. Two hares had skin lesions associated with tick bites with intralesional F. tularensis bacteria. CONCLUSIONS F. tularensis subsp. holarctica was isolated from ticks collected from the hares and cat, the first such reports in ticks in Sweden. Identification of the bacteria at the tick bite site and the more chronic character of the skin lesions compared to those of inner organs suggest that the ticks infected the hares. The cat showed no clinical signs of disease, suggesting that its tick was indeed the vector. These new findings suggest that ticks play a role in the transmission of F. tularensis to human and animal hosts in Sweden.
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Çakır Kıymaz Y, Bolat S, Katırcı B, Aldemir Ö, Altınkaya I, Mustafa Özcan M, Hopoğlu SM, Öz M, Keskin E, Öksüz C, Hasbek M, Aksoy A, Mahmutoğlu O, Çelik Seyitoğlu D, Büyüktuna SA, Elaldi N. The great tularemia outbreak in Sivas: Evaluation of 205 cases. Diagn Microbiol Infect Dis 2025; 111:116585. [PMID: 39549306 DOI: 10.1016/j.diagmicrobio.2024.116585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2024] [Revised: 10/22/2024] [Accepted: 10/28/2024] [Indexed: 11/18/2024]
Abstract
This study aimed to report a tularemia outbreak in Sivas and describe the epidemiological and diagnostic characteristics of the patients. Patients aged 18 and over followed up with a diagnosis of tularemia in Sivas Cumhuriyet University Hospital, Sivas Numune State Hospital, and Sivas State Hospital Infectious Diseases Outpatient Clinics and wards between November 2023 and May 2024 were evaluated. 205 adult patients with tularemia were included. The most common symptoms were sore throat (73.2 %, n=150), swelling in the neck (70.2 %, n = 144), and fatigue (55.1 %, n = 113). The most common form was oropharyngeal (82.4 %, n = 169) and glandular (14.6 %, n = 30). Lymphadenopathy was detected in 182 (88.8 %) patients, the most is cervical lymphadenopathy (60 %, n = 123). Lymph node drainage/excision was performed on 50 patients (24.3 %). There have been no deaths in this outbreak. This study presents patient data from the tularemia outbreak in Sivas.
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Kıymaz YÇ, Özbey M. A case of pulmonary tularemia mimicking lung cancer. Diagn Microbiol Infect Dis 2024; 110:116554. [PMID: 39406044 DOI: 10.1016/j.diagmicrobio.2024.116554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2024] [Revised: 10/04/2024] [Accepted: 10/07/2024] [Indexed: 11/03/2024]
Abstract
Tularemia is a zoonotic infectious disease caused by Francisella tularensis. The main reservoir for F. tularensis is lagomorphs, rodents, arthropods, and the hydrotelluric environment. It also can be transmitted by infected animals or by drinking contaminated water. Pulmonary tularemia is a rare form of tularemia mostly transmitted by inhalation. In this report, we present a 51-year-old male patient who was admitted to the hospital with fever, cough, sputum, and chest pain. Biopsy of the lesion compatible with mass on chest radiography revealed granulomatous inflammation. The diagnosis of pulmonary tularemia was made based on a history of rodent contact and tularemia microagglutination test (MAT): 1/1280.
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Maurin M, Hennebique A, Brunet C, Pondérand L, Pelloux I, Boisset S, Caspar Y. Non-vaccinal prophylaxis of tularemia. Front Microbiol 2024; 15:1507469. [PMID: 39669787 PMCID: PMC11635305 DOI: 10.3389/fmicb.2024.1507469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2024] [Accepted: 11/07/2024] [Indexed: 12/14/2024] Open
Abstract
Tularemia is a re-emerging zoonosis in many endemic countries. It is caused by Francisella tularensis, a gram-negative bacterium and biological threat agent. Humans are infected from the wild animal reservoir, the environmental reservoir or by the bite of arthropod vectors. This infection occurs through the cutaneous, conjunctival, digestive or respiratory routes. Tularemia generally manifests itself as an infection at the site of entry of the bacteria with regional lymphadenopathy, or as a systemic disease, particularly pulmonary. It is often a debilitating condition due to persistent symptoms and sometimes a life-threatening condition. There is effective antibiotic treatment for this disease but no vaccine is currently available for humans or animals. Due to the complexity of the F. tularensis life cycle and multiple modes of human infection, non-vaccine prophylaxis of tularemia is complex and poorly defined. In this review, we summarize the various individual prophylactic measures available against tularemia based on the different risk factors associated with the disease. We also discuss the currently underdeveloped possibilities for collective prophylaxis. Prophylactic measures must be adapted in each tularemia endemic area according to the predominant modes of human and animal infection. They requires a One Health approach to control both animal and environmental reservoirs of F. tularensis, as well as arthropod vectors, to slow the current expansion of endemic areas of this disease in a context of climate change.
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Esmaeili P, Khayatzadeh S, Maurin M, Gouya MM, Esmaeili S, Mostafavi E. Oropharyngeal tularemia outbreak linked to drinking contaminated tap water in North-Western Iran. Diagn Microbiol Infect Dis 2024; 110:116478. [PMID: 39146636 DOI: 10.1016/j.diagmicrobio.2024.116478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/17/2024]
Abstract
Tularemia is a widespread bacterial disease caused by Francisella tularensis. Iran is an endemic country for this zoonosis. In this report, we present a 2020 tularemia outbreak in a village in northwestern Iran involving 15 patients with the oropharyngeal form of the disease. This outbreak was probably linked to the consumption of contaminated drinking water.
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Çakır Kıymaz Y, Bolat S, Katırcı B, Aldemir Ö, Altınkaya I, Özcan MM, Hopoğlu SM, Öz M, Keskin E, Öksüz C, Topçu KF, Hasbek M, Doğan HO, Büyüktuna SA, Elaldı N. Evaluation of the clinical characteristics, laboratory parameters, and antibiotic treatment in patients diagnosed with tularemia. J Infect Chemother 2024:S1341-321X(24)00293-9. [PMID: 39481537 DOI: 10.1016/j.jiac.2024.10.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2024] [Revised: 10/08/2024] [Accepted: 10/27/2024] [Indexed: 11/02/2024]
Abstract
INTRODUCTION This retrospective, cross-sectional, multi-center study aimed to evaluate the impact of laboratory results and treatments on the treatment response in patients diagnosed with tularemia. METHODS The study included 190 adult patients diagnosed with tularemia between November 2023 and June 2024. RESULTS 67.9 % were female, mean age was 45.8 ± 14.9 years. The most frequently detected symptoms were sore throat (74.2 %), fatigue (71.6 %), and neck swelling (56.3 %). The most common form of tularemia was oropharyngeal (82.6 %) and glandular (14.2 %). The most used monotherapy was ciprofloxacin (80.5 %, n = 136), and combination therapy was streptomycin-ciprofloxacin (81.0 %, n = 17). Treatment failure was observed in 29 patients (15.2 %). No difference was found between patients who responded and didn't respond to treatment regarding laboratory parameters. Lymph node drainage or excision was performed in 47 patients (23 %). Suppurative lymphadenitis, abscess, necrosis, and conglomerate lymphadenopathy were more common in the lymph node drainage group. Reactive lymph nodes were more common in the group without lymph node drainage. There was no difference between the two groups regarding laboratory parameters of patients with and without lymph node drainage. The duration of antibiotic treatment was longer in patients who underwent lymph node drainage than in those who didn't. CONCLUSION Radiological evaluation of lymph nodes upon hospital admission, in addition to antibiotic therapy during treatment, may help predict which patients are more likely to require surgical drainage. Laboratory parameters may not provide significant benefits in predicting the need for lymph node drainage and long-term treatment did not affect the treatment response.
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Savas S, Sarıçam M. A Novel PCR-Free Ultrasensitive GQD-Based Label-Free Electrochemical DNA Sensor for Sensitive and Rapid Detection of Francisella tularensis. MICROMACHINES 2024; 15:1308. [PMID: 39597120 PMCID: PMC11596170 DOI: 10.3390/mi15111308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2024] [Revised: 10/21/2024] [Accepted: 10/24/2024] [Indexed: 11/29/2024]
Abstract
Biological warfare agents are infectious microorganisms or toxins capable of harming or killing humans. Francisella tularensis is a potential bioterrorism agent that is highly infectious, even at very low doses. Biosensors for biological warfare agents are simple yet reliable point-of-care analytical tools. Developing highly sensitive, reliable, and cost-effective label-free DNA biosensors poses significant challenges, particularly when utilizing traditional techniques such as fluorescence, electrochemical methods, and others. These challenges arise primarily due to the need for labeling, enzymes, or complex modifications, which can complicate the design and implementation of biosensors. In this study, we fabricated Graphene Quantum dot (GQD)-functionalized biosensors for highly sensitive label-free DNA detection. GQDs were immobilized on the surface of screen-printed gold electrodes via mercaptoacetic acid with a thiol group. The single-stranded DNA (ssDNA) probe was also immobilized on GQDs through strong π-π interactions. The ssDNA probe can hybridize with the ssDNA target and form double-stranded DNA, leading to a decrease in the effect of GQD but a positive shift associated with the increase in DNA concentration. The specificity of the developed system was observed with different microorganism target DNAs and up to three-base mismatches in the target DNA, effectively distinguishing the target DNA. The response time for the target DNA molecule is approximately 1010 s (17 min). Experimental steps were monitored using UV/Vis spectroscopy, Atomic Force Microscopy (AFM), and electrochemical techniques to confirm the successful fabrication of the biosensor. The detection limit can reach 0.1 nM, which is two-five orders of magnitude lower than previously reported methods. The biosensor also exhibits a good linear range from 105 to 0.01 nM and has good specificity. The biosensor's detection limit (LOD) was evaluated as 0.1 nM from the standard calibration curve, with a correlation coefficient of R2 = 0.9712, showing a good linear range and specificity. Here, we demonstrate a cost-effective, GQD-based SPGE/F. tularensis DNA test suitable for portable electrochemical devices. This application provides good perspectives for point-of-care portable electrochemical devices that integrate sample processing and detection into a single cartridge without requiring a PCR before detection. Based on these results, it can be concluded that this is the first enzyme-free electrochemical DNA biosensor developed for the rapid and sensitive detection of F. tularensis, leveraging the nanoenzyme and catalytic properties of GQDs.
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Pradhan K, Reuber EE, Sletten ET, Tomaso H, Seeberger PH. A Synthetic Oligosaccharide Resembling Francisella tularensis Strain 15 O-Antigen Capsular Polysaccharide as a Lead for Tularemia Diagnostics and Therapeutics. Angew Chem Int Ed Engl 2024:e202416432. [PMID: 39417793 DOI: 10.1002/anie.202416432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2024] [Revised: 09/19/2024] [Accepted: 09/19/2024] [Indexed: 10/19/2024]
Abstract
Francisella tularensis, a category A bioterrorism agent, causes tularemia in many animal species. F. tularensis subspecies tularensis (type A) and holarctica (type B) are mainly responsible for human tularemia. The high mortality rate of 30-60 % caused by F. tularensis subspecies tularensis if left untreated and the aerosol dispersal renders this pathogen a dangerous bioagent. While a live attenuated vaccine strain (LVS) of F. tularensis type B does not provide sufficient protection against all forms of tularemia infections, a significant level of protection against F. tularensis has been observed for both passive and active immunization of mice with isolated O-antigen capsular polysaccharide. Well-defined, synthetic oligosaccharides offer an alternative approach towards the development of glycoconjugate vaccines. To identify diagnostics and therapeutics leads against tularemia, a collection of F. tularensis strain 15 O-antigen capsular polysaccharide epitopes were chemically synthesized. Glycan microarrays containing synthetic glycans were used to analyze the sera of tularemia-infected and non-infected animals and revealed the presence of IgG antibodies against the glycans. Two disaccharide (13 and 18), both bearing a unique formamido moiety, were identified as minimal glycan epitopes for antibody binding. These epitopes are the starting point for the development of diagnostics and therapeutics against tularemia.
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Nikpour H, Hung CC, Lanka S, Barger AM, Reinhart JM. Clinical features of tularemia in cats: a retrospective study from 2000 to 2021. J Feline Med Surg 2024; 26:1098612X241275295. [PMID: 39466911 PMCID: PMC11529049 DOI: 10.1177/1098612x241275295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2024] [Indexed: 10/30/2024]
Abstract
OBJECTIVES The objectives of this study were to describe the clinical features of cats diagnosed with tularemia, and to compare the clinical features of cats with and without tularemia and identify characteristics increasing the likelihood of a tularemia diagnosis. METHODS Diagnostic laboratory data and medical records were retrospectively reviewed of cats tested for tularemia between 2000 and 2021. Clinical features including signalment, presenting complaint(s), physical examination findings and clinicopathologic data were described for cats with tularemia diagnosed by culture and/or PCR. Clinical features were also compared between PCR+ vs PCR- cats and logistic regression was used to identify features that predicted PCR+ status. RESULTS A total of 18 cats were diagnosed with tularemia. The affected cats had a mean age of 5.8 ± 4.9 years, with a slight male predominance. Most were domestic shorthair cats and had outdoor access. Common presenting complaints included lethargy and anorexia, while physical examination findings frequently revealed fever, peripheral lymphadenomegaly and oral ulcers. Laboratory findings varied, with notable abnormalities including neutrophilic inflammation observed on cytology and widespread acute systemic pathologic changes in necropsy results. Leukopenia and neutropenia were more common in PCR+ vs PCR- cats, and these factors were 7.4 times (confidence interval [CI] 1.2-62.3) and 10.0 times (CI 1.4-83.2) more likely to occur in PCR+ vs PCR- cats, respectively. There were no significant differences between the groups in other parameters including anemia, thrombocytopenia, band neutrophilia and hyperbilirubinemia. CONCLUSIONS AND RELEVANCE This study provides a more comprehensive description of tularemia in cats than has been available to date. In particular, leukopenia and neutropenia are significantly associated with tularemia-positive cats. These clinical features should be considered and raise suspicion for tularemia in cats. These findings may be valuable for the timely diagnosis, treatment and prevention of tularemia outbreaks in cats and humans.
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Thompson A, Brooks T, Houlihan C, Rampling T, Umpleby H, Hansford K, Medlock J, Vaux A, Logan J, Frost A, Neale S, Wyllie S, Dodgson K, Haigh D, Halim I, Huq R, Riste M, Gordon NC. Investigation of a Human Case of Francisella tularensis Infection, United Kingdom, 2023. Emerg Infect Dis 2024; 30:2188-2190. [PMID: 39320338 PMCID: PMC11431917 DOI: 10.3201/eid3010.240479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2024] Open
Abstract
Tularemia, caused by Francisella tularensis, is not known to occur in the United Kingdom. We report a case of tularemia diagnosed in July 2023 in a UK patient with no travel in the 6 weeks before symptom onset. We describe the subsequent multiagency investigation into possible routes of acquisition.
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Kara SS, Polat M, Erdeniz EH, Donmez AS. Pediatric Oropharyngeal Tularemia Cases: Challenges in Management. Vector Borne Zoonotic Dis 2024; 24:585-590. [PMID: 38651622 DOI: 10.1089/vbz.2023.0076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024] Open
Abstract
Background: Tularemia is one of the most prevalent zoonoses across the world. Patients in Turkiye mostly contract the oropharyngeal form, acquired through drinking, or contact with microorganism-contaminated water. Methods: Patients with oropharyngeal tularemia aged under 18 years and diagnosed between January 01, 2017, and December 31, 2020, were evaluated retrospectively. Tularemia was diagnosed in patients with compatible histories, symptoms, clinical presentations, and laboratory test results. Results: The mean age of 38 children was 12.1 ± 3.4 years, and the female/male ratio was 0.58 (14/24). The mean duration of symptoms on admission was 33.8 ± 26.2 days. All children had enlarged lymph nodes. Malaise, fever, and loss of appetite were other frequent symptoms. Patients were treated with antibiotics for a mean of 26.2 ± 18.8 days. Gentamycin was the most frequently used antibiotic (either alone or in combination) (n = 29, 76.3%). Twenty-six (68.4%) patients underwent surgical procedures in addition to antibiotherapy. Five (13.2%) required secondary total excision. Patients with higher leukocyte counts at admission received a combination of antibiotherapy plus surgery, rather than antibiotics alone. No relapses, reretreatment requirement, or mortality were observed after 12 months of follow-up. Conclusions: Oropharyngeal tularemia in children can require longer courses of antibiotic treatment with more than one drug and more frequent surgery than previously suggested in the literature, especially if the patients are admitted late to the hospital, symptom duration is prolonged, and appropriate treatment is initiated late. Higher leukocyte counts on admission may be prognostic for longer antibiotic treatment course and suppurative complications that require surgery. Raising awareness among patients and physicians is essential.
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Maddock KJ, Rickey CV, Pecoraro HL. Wild lagomorphs as potential sources of Francisella tularensis in an urban zoo: a case study. J Vet Diagn Invest 2024; 36:750-753. [PMID: 38653738 PMCID: PMC11457743 DOI: 10.1177/10406387241248608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024] Open
Abstract
A 9-y-old captive male Pallas' cat (Otocolobus manul) had a 1-mo history of worsening lameness and was euthanized. The animal was submitted to the North Dakota State University-Veterinary Diagnostic Laboratory for autopsy with differential diagnoses of suspected degenerative joint disease or neoplasia. Autopsy revealed icteric tissues and pinpoint foci in the liver, spleen, and all lung lobes. PCR testing was positive for Francisella tularensis, the causative agent of tularemia. Additional cases of tularemia were later identified in wild eastern cottontail rabbits found dead at the same urban zoo. Tularemia has been reported in captive non-human primates and rodent populations with one case linked to wild lagomorph exposure, which was likely the route of exposure in our Pallas' cat case. Tularemia is an occupational risk for zoo staff and laboratorians. Pest management and disease surveillance of wild lagomorph populations in zoos are important preventive measures.
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Jang J, Kwon DH, Jang JH, Lee DG, Chang SH, Jeon MY, Jeong YS, Song DH, Min JK, Park JG, Lee MS, Han BS, Yang W, Lee NK, Lee J. Development of a novel sandwich immunoassay based on targeting recombinant Francisella outer membrane protein A for the diagnosis of tularemia. Front Cell Infect Microbiol 2024; 14:1455259. [PMID: 39228894 PMCID: PMC11368854 DOI: 10.3389/fcimb.2024.1455259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Accepted: 08/01/2024] [Indexed: 09/05/2024] Open
Abstract
Introduction Tularemia, caused by the bacterium Francisella tularensis, poses health risks to humans and can spread through a variety of routes. It has also been classified as a Tier 1 Select agent by the CDC, highlighting its potential as a bioterrorism agent. Moreover, it is difficult to diagnose in a timely fashion, owing to the non-specific nature of tularemia infections. Rapid, sensitive, and accurate detection methods are required to reduce mortality rates. We aimed to develop antibodies directed against the outer membrane protein A of F. tularensis (FopA) for rapid and accurate diagnosis of tularemia. Methods We used a baculovirus insect cell expression vector system to produce the FopA antigen and generate anti-FopA antibodies through immunization of BALB/c mice. We then employed hybridoma and phage display technologies to screen for antibodies that could recognize unique epitopes on FopA. Result Two monoclonal antibodies, 6B12 and 3C1, identified through phage display screening specifically bound to recombinant FopA in a dose-dependent manner. The binding affinity of the anti-FopA 6B12 and 3C1 antibodies was observed to have an equilibrium dissociation constant of 1.76 × 10-10 M and 1.32 × 10-9 M, respectively. These antibodies were used to develop a sandwich ELISA system for the diagnosis of tularemia. This assay was found to be highly specific and sensitive, with detection limits ranging from 0.062 ng/mL in PBS to 0.064 ng/mL in skim milk matrices. Discussion Our findings demonstrate the feasibility of a novel diagnostic approach for detecting F. tularensis based on targeting FopA, as opposed to existing tests that target the bacterial lipopolysaccharide.
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Whiles S, Zhang Q, Chamberlain Z, Singh MK, Steele S, Zheng L, Rosche K, Huang W, Gao H, Zhang Q, Kawula T. Discovery of D8-03 as an Inhibitor of Intracellular Growth of Francisella tularensis. ACS Infect Dis 2024; 10:2775-2784. [PMID: 38876983 DOI: 10.1021/acsinfecdis.4c00116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2024]
Abstract
Francisella tularensis is a Gram-negative facultative intracellular bacterial pathogen that is classified by the Centers for Disease Control and Prevention as a Tier 1 Select Agent. F. tularensis infection causes the disease tularemia, also known as rabbit fever. Treatment of tularemia is limited to few effective antibiotics which are associated with high relapse rates, toxicity, and potential emergence of antibiotic-resistant strains. Consequently, new therapeutic options for tularemia are needed. Through screening a focused chemical library and subsequent structure-activity relationship studies, we have discovered a new and potent inhibitor of intracellular growth of Francisella tularensis, D8-03. Importantly, D8-03 effectively reduces bacterial burden in mice infected with F. tularensis. Preliminary mechanistic investigations suggest that D8-03 works through a potentially novel host-dependent mechanism and serves as a promising lead compound for further development.
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Bertelloni F, Cagnoli G, Interrante P, Ceccherelli R, Ebani VV. Molecular Survey on the Occurrence of Tick-Borne Bacteria in Wild Birds from Central Italy. Vet Sci 2024; 11:284. [PMID: 39057968 PMCID: PMC11281636 DOI: 10.3390/vetsci11070284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 06/06/2024] [Accepted: 06/21/2024] [Indexed: 07/28/2024] Open
Abstract
Birds are known to be carriers of ticks infected by tick-borne pathogens, including bacteria. However, not many studies have been carried out on avian tissues to detect these agents. The aim of the present survey was to investigate, using PCR, the presence of Anaplasma phagocytophilum, Bartonella spp., Borrelia burgdorferi sensu lato, Chlamydia psittaci, Coxiella burnetii, Ehrlichia canis, Francisella tularensis, and Rickettsia spp. in the spleens collected from 300 wild birds of different orders and species from Central Italy. A total of 53 (17.67%) samples were PCR positive for at least one investigated pathogen. One (0.33%) bird was positive for Bartonella spp., five (1.67%) birds were positive for C. burnetii, eleven (3.67%) for B. burgdorferi s.l., and thirty-six (12%) for C. psittaci. No coinfection was detected. All samples were negative for A. phagocytophilum, E. canis, F. tularensis, and Rickettsia spp. The findings showed that wild birds may harbor different zoonotic tick-borne bacteria; therefore, they can contribute to the diffusion of these agents.
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Cantlay S, Garrison NL, Patterson R, Wagner K, Kirk Z, Fan J, Primerano DA, Sullivan MLG, Franks JM, Stolz DB, Horzempa J. Corrigendum: Phenotypic and transcriptional characterization of F. tularensis LVS during transition into a viable but non-culturable state. Front Microbiol 2024; 15:1407526. [PMID: 38711966 PMCID: PMC11071173 DOI: 10.3389/fmicb.2024.1407526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 04/08/2024] [Indexed: 05/08/2024] Open
Abstract
[This corrects the article DOI: 10.3389/fmicb.2024.1347488.].
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Pavkova I, Bavlovic J, Kubelkova K, Stulik J, Klimentova J. Protective potential of outer membrane vesicles derived from a virulent strain of Francisella tularensis. Front Microbiol 2024; 15:1355872. [PMID: 38533334 PMCID: PMC10963506 DOI: 10.3389/fmicb.2024.1355872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/12/2024] [Indexed: 03/28/2024] Open
Abstract
Francisella tularensis secretes tubular outer membrane vesicles (OMVs) that contain a number of immunoreactive proteins as well as virulence factors. We have reported previously that isolated Francisella OMVs enter macrophages, cumulate inside, and induce a strong pro-inflammatory response. In the current article, we present that OMVs treatment of macrophages also enhances phagocytosis of the bacteria and suppresses their intracellular replication. On the other hand, the subsequent infection with Francisella is able to revert to some extent the strong pro-inflammatory effect induced by OMVs in macrophages. Being derived from the bacterial surface, isolated OMVs may be considered a "non-viable mixture of Francisella antigens" and as such, they present a promising protective material. Immunization of mice with OMVs isolated from a virulent F. tularensis subsp. holarctica strain FSC200 prolonged the survival time but did not fully protect against the infection with a lethal dose of the parent strain. However, the sera of the immunized animals revealed unambiguous cytokine and antibody responses and proved to recognize a set of well-known Francisella immunoreactive proteins. For these reasons, Francisella OMVs present an interesting material for future protective studies.
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Güler E, Güvenir M, Korbay B, Kiraz A, Süer K. Investigation of Francisella tularensis Seroprevalence and Determination of Risk Factors for Tularemia among Hunters in Northern Cyprus. J Arthropod Borne Dis 2024; 18:47-56. [PMID: 39005541 PMCID: PMC11239370 DOI: 10.18502/jad.v18i1.15671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 12/03/2023] [Indexed: 07/16/2024] Open
Abstract
Background Tularemia is a zoonotic disease (reservoir is usually rodents) caused by Francisella tularensis, especially seen in the northern hemisphere. Hunters are in the risk group for this disease. In this study, it was aimed to determine the seroprevalence of tularemia among hunters and determine the risk factors of tularemia in our country. Methods The Turkish Republic of Northern Cyprus (TRNC) is divided into four regions (Nicosia, Kyrenia, Famagusta/Trikomo, and Morphou/Lefka) and 100 volunteer hunters randomly selected from these regions were included in our study. Tube agglutination test (TAT) and F. tularensis IgG and IgM (ELISA method) were applied in all sera. All hunters were filled with a pre-prepared questionnaire to determine risk factors for tularemia. Results TAT positivity was found in 11%. While F. tularensis ELISA IgG positivity was 17%, IgM positivity was not found in any hunters. Hunters with positive F. tularensis ELISA IgG test (17%) were accepted as seropositive in terms of tularemia. There was no statistically significant difference between the mean age of IgG-positive and negative hunters (p= 0.915). Of the 86 hunters who kept at least one hunting dog in their garden, 15 (17.4%) were IgG-positive. There was no significant relationship between feeding hunting dogs and tularemia (p= 0.561). Conclusion Our study showed that the seroprevalence of tularemia was high (17%) among hunters, who are considered a risk group, in our country. We think that more epidemiological research should be done on tularemia infection and it should not be overlooked in the clinic.
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Azimi T, Nasrollahian S, Sabour S, Hadi N, Azimi L, Fallah F, Pourmand MR. Detection of Yersinia enterocolitica, Shigella spp. and Salmonella spp. in Rattus norvegicus captured from Tehran, Iran. Future Microbiol 2024; 19:377-384. [PMID: 38305237 DOI: 10.2217/fmb-2023-0138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/17/2023] [Indexed: 02/03/2024] Open
Abstract
Background: The present study aims to determine the presence of Yersinia spp., Yersinia pestis, Yersinia enterocolitica pathogen, Listeria monocytogenes, Salmonella spp., Shigella spp., Francisella tularensis and Borrelia spp. in brown rats of Tehran, Iran. Methods: PCR was used to detect various bacteria in 100 brown rats, Also, ELISA was used to detect antibodies against the F. tularensis and Borrelia spp. Results: A total of 16% and 13% of fecal samples were positive for Yersinia spp. and Y. enterocolitica pathogen. ELISA results were negative for F. tularensis and Borrelia. No specific antibodies (IgG) were against these bacteria. Conclusion: According to the results of our analysis, rats are significant transmitters and carriers of a variety of illnesses that can spread to both people and other animals.
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Herron ICT, Laws TR, Nelson M. Marmosets as models of infectious diseases. Front Cell Infect Microbiol 2024; 14:1340017. [PMID: 38465237 PMCID: PMC10921895 DOI: 10.3389/fcimb.2024.1340017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/29/2024] [Indexed: 03/12/2024] Open
Abstract
Animal models of infectious disease often serve a crucial purpose in obtaining licensure of therapeutics and medical countermeasures, particularly in situations where human trials are not feasible, i.e., for those diseases that occur infrequently in the human population. The common marmoset (Callithrix jacchus), a Neotropical new-world (platyrrhines) non-human primate, has gained increasing attention as an animal model for a number of diseases given its small size, availability and evolutionary proximity to humans. This review aims to (i) discuss the pros and cons of the common marmoset as an animal model by providing a brief snapshot of how marmosets are currently utilized in biomedical research, (ii) summarize and evaluate relevant aspects of the marmoset immune system to the study of infectious diseases, (iii) provide a historical backdrop, outlining the significance of infectious diseases and the importance of developing reliable animal models to test novel therapeutics, and (iv) provide a summary of infectious diseases for which a marmoset model exists, followed by an in-depth discussion of the marmoset models of two studied bacterial infectious diseases (tularemia and melioidosis) and one viral infectious disease (viral hepatitis C).
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Cantlay S, Garrison NL, Patterson R, Wagner K, Kirk Z, Fan J, Primerano DA, Sullivan MLG, Franks JM, Stolz DB, Horzempa J. Phenotypic and transcriptional characterization of F. tularensis LVS during transition into a viable but non-culturable state. Front Microbiol 2024; 15:1347488. [PMID: 38380104 PMCID: PMC10877056 DOI: 10.3389/fmicb.2024.1347488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
Francisella tularensis is a gram-negative, intracellular pathogen which can cause serious, potentially fatal, illness in humans. Species of F. tularensis are found across the Northern Hemisphere and can infect a broad range of host species, including humans. Factors affecting the persistence of F. tularensis in the environment and its epidemiology are not well understood, however, the ability of F. tularensis to enter a viable but non-culturable state (VBNC) may be important. A broad range of bacteria, including many pathogens, have been observed to enter the VBNC state in response to stressful environmental conditions, such as nutrient limitation, osmotic or oxidative stress or low temperature. To investigate the transition into the VBNC state for F. tularensis, we analyzed the attenuated live vaccine strain, F. tularensis LVS grown under standard laboratory conditions. We found that F. tularensis LVS rapidly and spontaneously enters a VBNC state in broth culture at 37°C and that this transition coincides with morphological differentiation of the cells. The VBNC bacteria retained an ability to interact with both murine macrophages and human erythrocytes in in vitro assays and were insensitive to treatment with gentamicin. Finally, we present the first transcriptomic analysis of VBNC F. tularensis, which revealed clear differences in gene expression, and we identify sets of differentially regulated genes which are specific to the VBNC state. Identification of these VBNC specific genes will pave the way for future research aimed at dissecting the molecular mechanisms driving entry into the VBNC state.
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Mlynek KD, Toothman RG, Martinez EE, Qiu J, Richardson JB, Bozue JA. Mutation of wbtJ, a N-formyltransferase involved in O-antigen synthesis, results in biofilm formation, phase variation and attenuation in Francisella tularensis. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001437. [PMID: 38421161 PMCID: PMC10924466 DOI: 10.1099/mic.0.001437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 01/29/2024] [Indexed: 03/02/2024]
Abstract
Two clinically important subspecies, Francisella tularensis subsp. tularensis (type A) and F. tularensis subsp. holarctica (type B) are responsible for most tularaemia cases, but these isolates typically form a weak biofilm under in vitro conditions. Phase variation of the F. tularensis lipopolysaccharide (LPS) has been reported in these subspecies, but the role of variation is unclear as LPS is crucial for virulence. We previously demonstrated that a subpopulation of LPS variants can constitutively form a robust biofilm in vitro, but it is unclear whether virulence was affected. In this study, we show that biofilm-forming variants of both fully virulent F. tularensis subspecies were highly attenuated in the murine tularaemia model by multiple challenge routes. Genomic sequencing was performed on these strains, which revealed that all biofilm-forming variants contained a lesion within the wbtJ gene, a formyltransferase involved in O-antigen synthesis. A ΔwbtJ deletion mutant recapitulated the biofilm, O-antigen and virulence phenotypes observed in natural variants and could be rescued through complementation with a functional wbtJ gene. Since the spontaneously derived biofilm-forming isolates in this study were a subpopulation of natural variants, reversion events to the wbtJ gene were detected that eliminated the phenotypes associated with biofilm variants and restored virulence. These results demonstrate a role for WbtJ in biofilm formation, LPS variation and virulence of F. tularensis.
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Maurin M, Pondérand L, Hennebique A, Pelloux I, Boisset S, Caspar Y. Tularemia treatment: experimental and clinical data. Front Microbiol 2024; 14:1348323. [PMID: 38298538 PMCID: PMC10827922 DOI: 10.3389/fmicb.2023.1348323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 12/31/2023] [Indexed: 02/02/2024] Open
Abstract
Tularemia is a zoonosis caused by the Gram negative, facultative intracellular bacterium Francisella tularensis. This disease has multiple clinical presentations according to the route of infection, the virulence of the infecting bacterial strain, and the underlying medical condition of infected persons. Systemic infections (e.g., pneumonic and typhoidal form) and complications are rare but may be life threatening. Most people suffer from local infection (e.g., skin ulcer, conjunctivitis, or pharyngitis) with regional lymphadenopathy, which evolve to suppuration in about 30% of patients and a chronic course of infection. Current treatment recommendations have been established to manage acute infections in the context of a biological threat and do not consider the great variability of clinical situations. This review summarizes literature data on antibiotic efficacy against F. tularensis in vitro, in animal models, and in humans. Empirical treatment with beta-lactams, most macrolides, or anti-tuberculosis agents is usually ineffective. The aminoglycosides gentamicin and streptomycin remain the gold standard for severe infections, and the fluoroquinolones and doxycycline for infections of mild severity, although current data indicate the former are usually more effective. However, the antibiotic treatments reported in the literature are highly variable in their composition and duration depending on the clinical manifestations, the age and health status of the patient, the presence of complications, and the evolution of the disease. Many patients received several antibiotics in combination or successively. Whatever the antibiotic treatment administered, variable but high rates of treatment failures and relapses are still observed, especially in patients treated more then 2-3 weeks after disease onset. In these patients, surgical treatment is often necessary for cure, including drainage or removal of suppurative lymph nodes or other infectious foci. It is currently difficult to establish therapeutic recommendations, particularly due to lack of comparative randomized studies. However, we have attempted to summarize current knowledge through proposals for improving tularemia treatment which will have to be discussed by a group of experts. A major factor in improving the prognosis of patients with tularemia is the early administration of appropriate treatment, which requires better medical knowledge and diagnostic strategy of this disease.
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Kuhnert P, Brodard I, Ackermann S, Schierack P, Jores J. Serological and molecular detection as well as typing of Leptospira spp. in foxes, raccoons, and other wild carnivores in North-Eastern Germany, 2021-2022. Heliyon 2024; 10:e23268. [PMID: 38163163 PMCID: PMC10756992 DOI: 10.1016/j.heliyon.2023.e23268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/20/2023] [Accepted: 11/29/2023] [Indexed: 01/03/2024] Open
Abstract
Leptospirosis is a worldwide zoonosis caused by pathogenic Leptospira spp. While the latter are reported from various mammal hosts such as humans, dogs, or rodents, less is known about their presence in wild carnivores. We therefore investigated the presence of Leptospira spp. in foxes, raccoons, badgers, raccoon dogs, and martens in North-Eastern Germany. Kidney, urine, and blood specimens obtained from legally hunted or road-killed animals were tested by real-time PCR and by serogroup specific antibody detection for the presence of Leptospira spp. Additionally, kidney and urine specimens were tested by real-time PCR for the presence of Brucella spp. and Francisella tularensis, with all being negative for these two zoonotic pathogens. Leptospira spp. were detected by PCR in 12.6 % (n = 21/166) and serologically in 26.2 % (n = 53/202) of tissue and serum samples, respectively. Antibodies to 15 different serogroups were identified with Javanica (n = 25) and Bataviae (n = 12) being predominant. A high sero-prevalence of 34.0 % and 18.6 % in foxes and raccoons, respectively, and the presence of ST17 associated with human and animal leptospirosis indicates a reservoir and the zoonotic potential of these wild animals.
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Isidro J, Escudero R, Luque-Larena JJ, Pinto M, Borges V, González-Martín-Niño R, Duarte S, Vieira L, Mougeot F, Vidal D, Herrera-Rodríguez D, Rodríguez-Pastor R, Herrero-Cófreces S, Jubete-Tazo F, Gomes JP, Lopes de Carvalho I. Strengthening the genomic surveillance of Francisella tularensis by using culture-free whole-genome sequencing from biological samples. Front Microbiol 2024; 14:1277468. [PMID: 38249473 PMCID: PMC10797068 DOI: 10.3389/fmicb.2023.1277468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 11/23/2023] [Indexed: 01/23/2024] Open
Abstract
Introduction Francisella tularensis is a highly infectious bacterium that causes the zoonotic disease tularemia. The development of genotyping methods, especially those based on whole-genome sequencing (WGS), has recently increased the knowledge on the epidemiology of this disease. However, due to the difficulties associated with the growth and isolation of this fastidious pathogen in culture, the availability of strains and subsequently WGS data is still limited. Methods To surpass these constraints, we aimed to implement a culture-free approach to capture and sequence F. tularensis genomes directly from complex samples. Biological samples obtained from 50 common voles and 13 Iberian hares collected in Spain were confirmed as positive for F. tularensis subsp. holarctica and subjected to a WGS target capture and enrichment protocol, using RNA oligonucleotide baits designed to cover F. tularensis genomic diversity. Results We obtained full genome sequences of F. tularensis from 13 animals (20.6%), two of which had mixed infections with distinct genotypes, and achieved a higher success rate when compared with culture-dependent WGS (only successful for two animals). The new genomes belonged to different clades commonly identified in Europe (B.49, B.51 and B.262) and subclades. Despite being phylogenetically closely related to other genomes from Spain, the detected clusters were often found in other countries. A comprehensive phylogenetic analysis, integrating 599 F. tularensis subsp. holarctica genomes, showed that most (sub)clades are found in both humans and animals and that closely related strains are found in different, and often geographically distant, countries. Discussion Overall, we show that the implemented culture-free WGS methodology yields timely, complete and high-quality genomic data of F. tularensis, being a highly valuable approach to promote and potentiate the genomic surveillance of F. tularensis and ultimately increase the knowledge on the genomics, ecology and epidemiology of this highly infectious pathogen.
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