Search Results (79)

Background: Inhalational antibiotics have been used effectively to treat chronic diseases such as Pseudomonas aeruginosa infections associated with cystic fibrosis. This approach may enhance treatment options for difficult-to-treat, acute pneumonic diseases. Liposomal encapsulated ciprofloxacin (Lipoquin and/or Apulmiq) has provided protection in murine models of plague, anthrax, Q fever and tularemia. Development of the ability to deliver these drugs to nonhuman primates (NHPs) would enable further extrapolation of the data observed in small animal models of infection to humans. Methods: In this study, the methodology was established to deliver Apulmiq to common marmosets (Callithrix jacchus). Marmosets were anaesthetised with a novel, reversible anaesthetic comprising fentanyl, medetomidine and midazolam (FMM). They were placed into plethysmography tubes with their heads in an exposure chamber. The LC Sprint jet nebuliser or Pari eFlow Rapid nebuliser were used to aerosolise Apulmiq into the exposure chamber. Animals were euthanised after dosing and the concentration of ciprofloxacin was assessed in the plasma and lungs of the animals. Results: Non-compartmental pharmacokinetic analysis determined that a 30 min exposure of drug was required to reach a human-equivalent target dose of 0.8 mg/kg body weight in the lungs. Conclusions: This approach can now be used to assess the efficacy of inhalational liposomal ciprofloxacin in NHP infection models. Full article

A 47-year-old woman presented with fever, fatigue, night sweats and inguinal glandular swelling following a tick bite. Weeks of diagnostic uncertainty followed, and a lymph node biopsy was sent to be investigated for tularemia and pathology. An ¹⁸F-FDG PET/CT scan was performed due to a suspicion of malignant lymphoma. The scan revealed high metabolic activity in the left inguinal region, which was compatible with abscesses. The diagnosis of glandular tularemia was established on a positive PCR for Francisella tularensis (F. tularensis) and positive F. tularensis serology. This case highlights the challenges of diagnosing tularemia and illustrates the role of imaging. Full article

Background: Tularemia is a rare zoonosis caused by the bacterium Francisella tularensis. In the head and neck region, it can manifest as cervical lymphadenopathy. Despite intensive therapy with various antibiotics, there is often a prolonged medical course. Methods: In this paper, all documented cases of tularemia in the head and neck region at the Medical University of Innsbruck (Austria) are analyzed and the results compared with the literature. A retrospective analysis of all patients diagnosed with tularemia at the Department of Otorhinolaryngology-Head and Neck Surgery, Medical University of Innsbruck (Austria), was performed. Tularemia was diagnosed using a serologic agglutination antibody test. Results: Thirteen patients with tularemia presented at the Department of Otorhinolaryngology-Head and Neck Surgery, Medical University of Innsbruck (Austria), between 2010 and 2024. In 10 patients (10/13; 77%), animal contact or an insect bite was the suspected cause. The mean time from the onset of the first symptoms to diagnosis was 36 ± 15 days. The therapy took a mean of 5 ± 2 months until the last follow-up. On average, the patients were treated with 4 ± 1 different antibiotics. The median duration of hospital stay was 13 days (range: 0–36). In addition, a median of 9 (range: 2–20) further outpatient check-ups with several neck ultrasounds were carried out. Also, 10 patients (10/13; 77%) received a diagnostic and/or therapeutic surgical intervention. Conclusions: Tularemia is a rare infectious disease with a prolonged diagnostic and therapeutic course. Screening for tularemia should be performed in cases of cervical lymphadenopathy, especially if empirical antibiotic treatment has been ineffective or if there is a specific medical history. Full article

North American beavers (Castor canadensis) are semi-aquatic rodents recognized as keystone species because they increase the diversity of freshwater ecosystems. This study aimed to characterize the mortality and pathological findings in free-ranging beavers in California and, based on these results, identify potential threats to freshwater ecosystems. This study included 18 beavers submitted for postmortem examination at the California Animal Health and Food Safety Laboratory, UC Davis, between 2008 and 2024. Gross and microscopic examinations, and bacteriological, parasitological, immunohistochemical, and molecular techniques, were used as tools to diagnose the cause of death/reason for euthanasia and comorbidities in the beavers. Baylisascaris spp.-associated or -suspected encephalitis was the most prevalent (9/18, 50%) cause of mortality/reason for euthanasia, followed by bacterial infections in six individuals. In these six animals, bacterial bronchopneumonia was diagnosed in two (Staphylococcus aureus and a mix of Gram-negative and -positive bacterial infection) and Listeria monocytogenes encephalitis, bacterial myofascitis (Aeromonas bestiarum and Pasteurella multocida), bacterial encephalitis (Acinetobacter towneri), and tularemia (Francisella tularensis) were diagnosed in one beaver each. Three animals died or were euthanized due to non-infectious causes, including motor vehicle trauma, squamous cell carcinoma, and capture cardiomyopathy. Endoparasitism was the main comorbidity, including granulomatous hepatitis caused by a suspected capillarid species, cerebral toxoplasmosis, Giardia infection, gastric nematodiasis, and cecal trematodiasis. In California, beavers are exposed to various pathogens that represent threats to humans, domestic animals, and wildlife. Since the interspecies transmission of these pathogens occurs in rivers, streams, lakes, and ponds, we suggest that studying beaver health can reflect freshwater ecosystem health. This study also indicates that the translocation of beavers to new areas without consideration and/or mitigation represents a potential risk of pathogen introduction. Full article

Francisella tularensis is a vector-borne zoonotic bacterium that causes tularemia, a disease of great importance for animal and public health. Although wild lagomorphs are considered one of the major reservoirs of this bacterium, information about the circulation of F. tularensis in European wild rabbit (Oryctolagus cuniculus) and Iberian hare (Lepus granatensis) populations in Europe is still very limited. In Spain, F. tularensis is present in northern central regions, with recurrent outbreaks occurring annually. However, southern Spain has been neglected in terms of monitoring and research. Thus, the aim of this study was to investigate the occurrence of F. tularensis in wild lagomorphs in the Mediterranean ecosystems of southern Spain through using molecular techniques. Spleen samples from 774 European wild rabbits and 178 Iberian hares were collected on 135 hunting grounds between the 2017/2018 and 2022/2023 hunting seasons. A primer set targeting the 16S rRNA gene was used for the detection of F. tularensis DNA. None of the 952 (0.0%; 95%CI: 0.0–0.4) wild lagomorphs sampled showed presence of F. tularensis DNA. Our finding indicates the absence or very low circulation of the bacterium in wild rabbit and Iberian hare populations in the Mediterranean ecosystems of southern Spain, denoting a limited risk of transmission of this pathogen from wild lagomorphs to other sympatric species, including human beings, in this Iberian region. Full article

Tularemia is an acute infectious disease classified as a natural focal infection, requiring continuous monitoring of both human and animal morbidity, as well as tracking of pathogen circulation in natural reservoirs and vectors. These efforts are essential for a comprehensive prevention and containment strategy. The causative agent, Francisella tularensis, comprises three subspecies—tularensis, holarctica, and mediasiatica—which differ in their geographic distribution and virulence. The ability to directly detect the pathogen and differentiate between subspecies has enhanced diagnostics and allowed a more accurate identification of circulation areas. Real-time PCR protocols for identification of F. tularensis subspecies tularensis and holarctica have been developed, utilizing specific primers and probes that target unique genomic regions. In this study, we present the development of a new real-time PCR assay for the detection of Francisella spp. and differentiation of F. tularensis subsp. mediasiatica. The specificity of the assay was tested on DNA from 86 bacterial species across 31 families unrelated to Francisella spp., as well as on DNA collections of F. tularensis subsp. mediasiatica and F. tularensis subsp. holarctica. The limit of detection (LOD95%) for real-time PCR in detecting Francisella spp. was 0.297 fg (0.145 genomic equivalents, GE) for holarctica DNA and 0.733 fg (0.358 GE) for mediasiatica DNA. The LOD95% for subspecies differential identification of mediasiatica was 8.156 fg (3.979, GE). The high sensitivity and specificity of these developed protocols enable direct detection of pathogens in biological and environmental samples, thereby improving the efficiency of tularemia surveillance in Kazakhstan. Full article

Francisella is a highly infectious gram-negative bacterium that causes tularemia in humans and animals. It can survive and multiply in a variety of cells, including macrophages, dendritic cells, amoebae, and arthropod-derived cells. However, the intracellular life cycle of a bacterium varies depending on the cell type. Shortly after the infection of mammalian cells, the bacterium escapes the phagosome into the cytosol, where it replicates. In contrast, in the amoebae Acanthamoeba castellanii and Hartmannella vermiformis, the bacterium replicates within the membrane-bound vacuole. In recent years, the amoeba Dictyostelium discoideum has emerged as a powerful model to study the intracellular cycle and virulence of many pathogenic bacteria. In this study, we used D. discoideum as a model for the infection and isolation of Francisella novicida-containing vacuoles (FCVs) formed after bacteria invade the amoeba. Our results showed that F. novicida localized in a vacuole after invading D. discoideum. Here, we developed a method to isolate FCV and determined its composition by proteomic analyses. Proteomic analyses revealed 689 proteins, including 13 small GTPases of the Rab family. This is the first evidence of F. novicida-containing vacuoles within amoeba, and this approach will contribute to our understanding of host–pathogen interactions and the process of pathogen vacuole formation, as vacuoles containing bacteria represent direct contact between pathogens and their hosts. Furthermore, this method can be translocated on other amoeba models. Full article

In addition to common skin pathogens, acute focal lymphadenitis in humans can, in rare cases, be caused by a zoonotic pathogen. Furthermore, it can develop in the absence of any direct or indirect contact with infected animals, in cases when the microorganism is transmitted by a vector. These clinical entities are rare, and therefore often not easily recognized, yet many zoonotic illnesses are currently considered emerging or re-emerging in many regions. Focal zoonotic vector-borne lymphadenitis and its numerous causative agents, with their variegated clinical manifestations, have been described in some case reports and small case series. Therefore, we summarized those data in this narrative overview, with the aim of raising clinical awareness, which could improve clinical outcomes. This overview briefly covers reported pathogens, their vectors and geographic distribution, and their main clinical manifestations, diagnostic possibilities, and recommended therapy. Vector-borne tularemia, plague, bartonellosis, rickettsioses, borreliosis, and Malayan filariasis are mentioned. According to the existing data, when acute focal bacterial vector-borne zoonotic lymphadenitis is suspected, in severe or complicated cases it seems prudent to apply combined aminoglycoside (or quinolone) plus doxycycline as an empirical therapy, pending definite diagnostic results. In this field, the “one health approach” and further epidemiological and clinical studies are needed. Full article

Background and Objectives: Parinaud oculoglandular syndrome (POS) is unilateral granulomatous follicular conjunctivitis with ipsilateral afferent lymphadenopathy, primarily caused by cat-scratch disease, tularemia, and sporotrichosis. We report a case of POS in which Bartonella DNA was detected using polymerase chain reaction (PCR) in corneal and conjunctival specimens. Methods: A 29-year-old man, who started keeping a stray cat two months prior, became aware of right preauricular lymphadenopathy and right ocular conjunctival hyperemia one month prior. Subsequently, he developed a fever of approximately 37.9 °C, with a purulent ocular discharge appearing 1 week before being referred to our department for a detailed ophthalmological examination. The patient’s right eye showed hyperemia and edema in the bulbar conjunctiva, along with palpebral conjunctival hyperemia, follicles, and white ulcers. Two weeks later, his serum IgM titer for Bartonella henselae was 1:20, and Bartonella DNA was detected by PCR in the corneal and conjunctival specimens. Based on these findings, the patient was diagnosed with POS caused by cat-scratch disease (CSD). Oral doxycycline, rifampicin, topical gatifloxacin, betamethasone phosphate, and erythromycin eye ointments were prescribed. Results: After 2 weeks of oral treatment and 2 months of eye drop treatment, the deterioration of the cornea and conjunctiva improved when the patient recovered good visual acuity. Conclusions: PCR assays of corneal and conjunctival specimens are useful for the diagnosis of CSD presenting with POS. These results suggested that Bartonella may be directly involved in the ocular surface pathogenesis of POS. Full article

Tularemia is an acute febrile disease caused by the Gram-negative bacillus Francisella tularensis. Based on genetic and phenotypic characteristics, three subspecies are distinguished: tularensis, holarctica, and mediasiatica. F. tularensis subsp. mediasiatica remains the least studied subspecies. Over the past decade, new foci of distribution of F. tularensis subsp. mediasiatica have been discovered in Russia (Siberia), expanding the possible distribution area by thousands of kilometers. This article provides whole genome single nucleotide polymorphism (wgSNP) and polymorphic tandem repeats (MLVA) analyses of 28 mediasiatica strains isolated between 1965 and 2004 in Kazakhstan. Despite high genetic homogeneity, MLVA with eleven loci (MLVA11) demonstrates a high discriminatory ability (diversity index, 0.9497). The topological structure of the trees based on wgSNP and MLVA is not comparable; however, clustering remains congruent for most outbreaks, with the exception of two strains from one outbreak that are identical in terms of wgSNP but differ at three tandem repeat loci. Based on wgSNP, the strains are assigned to one of the three currently known mediasiatica sublineages, lineage M.I, together with other historical strains maintained in collections in Russia and Sweden. wgSNP shows limited previously unknown genetic diversity, with the M.I lineage size being only 118 SNPs. The wgSNP genotype is not strongly correlated with year and place of isolation. Full article

Francisella tularensis subspecies tularensis is a category-A biothreat agent that can cause lethal tularemia. Ceftobiprole medocaril is being explored as a medical countermeasure for the treatment of pneumonic tularemia. The efficacy of ceftobiprole medocaril against inhalational tularemia was evaluated in the Fischer 344 rat model of infection. The dose was expected to be effective against F. tularensis isolates with ceftobiprole minimum inhibitory concentrations ≤0.5 µg/mL. Animals treated with ceftobiprole medocaril exhibited a 92% survival rate 31 days post-challenge, identical to the survival of levofloxacin-treated rats. By comparison, rats receiving placebo experienced 100% mortality. Terminally collected blood, liver, lung, and spleen samples confirmed disseminated F. tularensis infections in most animals that died prior to completing treatments (placebo animals and a rat treated with ceftobiprole medocaril), although levels of bacteria detected in the placebo samples were significantly elevated compared to the ceftobiprole-medocaril-treated group geometric mean. Furthermore, no evidence of infection was detected in any rat that completed ceftobiprole medocaril or levofloxacin treatment and survived to the end of the post-treatment observation period. Overall, survival rates, body weights, and bacterial burdens consistently demonstrated that treatment with ceftobiprole medocaril is efficacious against otherwise fatal cases of pneumonic tularemia in the rat model. Full article

In 2020, a record number of tick-borne encephalitis (TBE) cases was reported in major endemic areas in Germany, i.e., the southern federal states of Baden-Wuerttemberg and Bavaria. Most cases were unvaccinated. Other tick-borne diseases (TBDs), including Lyme borreliosis and tularemia, are rising, too. Thus, strategies are needed to increase TBE vaccination uptake in risk areas and promote education on TBD prevention. Primary care physicians are key providers of both vaccinations and TBD education. The TBD-Prevention (TBD-Prev) study aimed to investigate the knowledge, attitudes and behaviors of primary care physicians in Baden-Wuerttemberg and Bavaria with regard to TBE vaccination and prevention of TBDs and to derive strategies for increasing vaccination rates and improving knowledge about TBE and other TBDs in the population and among primary care physicians. We invited all primary care physicians (N = 14,046) in both states to participate by mail. Using standardized, self-administered questionnaires, available both on paper and online, we asked physicians anonymously about their knowledge, attitudes and behaviors with respect to TBE vaccination and TBD prevention and their need for further information/educational materials. A total of 2321 physicians participated between May and September 2022 (response rate 17%), of whom 1222 (53%) worked in Baden-Wuerttemberg and 1067 (46%) in Bavaria. Among the participating physicians, 56% were male, 71% were >50 years and 51% worked in an individual practice. Furthermore, 91% were aware of the German national vaccination guidelines, and 98% perceived their knowledge of the risks and benefits of vaccination as adequate. A total of 97% offer TBE vaccinations, 67% provide vaccination counselling during initial consultations with new patients and 64% actively remind patients about due vaccinations. In addition, 24% expressed a need for further information materials, mainly traditional, analogue media such as flyers (82%) and posters (50%), and named timeliness, quality assurance, easy comprehensibility and independence from the pharmaceutical industry as the most important characteristics of such materials. Almost all participating physicians reported offering TBE vaccinations and feeling well-informed about TBE vaccination and TBDs. However, active offering of vaccinations and education could be further improved, and additional, low-threshold information materials are needed. Based on these results, we will develop and provide various materials on TBE vaccination and TBDs, in particular flyers and posters, for use by physicians during consultations. Full article

Francisella tularensis is a zoonotic bacterium that is endemic in large parts of the world. It is absent in the standard library of the most applied matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems: the Vitek MS and the Bruker Biotyper system. The additional Bruker MALDI Biotyper Security library contains F. tularensis without subspecies differentiation. The virulence of F. tularensis differs between the subspecies. The F. tularensis subspecies (ssp.) tularensis is highly pathogenic, whereas the subspecies holarctica displays lower virulence and subspecies novicida and F. tularensis ssp. mediasiatica are hardly virulent. To differentiate the Francisellaceae and the F. tularensis-subspecies, an in-house Francisella library was built with the Bruker Biotyper system and validated together with the existing Bruker databases. In addition, specific biomarkers were defined based on the main spectra of the Francisella strains supplemented with in silico genome data. Our in-house Francisella library accurately differentiates the F. tularensis subspecies and the other Francisellaceae. The biomarkers correctly differentiate the various species within the genus Francisella and the F. tularensis subspecies. These MALDI-TOF MS strategies can successfully be applied in a clinical laboratory setting as a fast and specific method to identify F. tularensis to subspecies level. Full article

Russia has a number of historical foci of zoonotic anthropogenic diseases. In Central Russia, the Republic of Mordovia is one of such areas, a region being known to have foci of haemorrhagic fever with renal syndrome (HFRS) and tularemia. It therefore requires continuous monitoring. The role of small terrestrial mammals as reservoirs of zoonoses has been previously proven for the region. The aim of this work is to take an integrated approach to assess the role of terrestrial and subterranean small mammals. Subterranean mammals are often not considered important reservoirs of zoonotic pathogens that cause human morbidity. Among small mammals in the wild environment, the bank vole, the yellow-necked mouse and the house mouse play important roles as vectors of zoonoses. Among wild subterranean mammals, the greater mole rat is important as a vector of tularemia and HFRS. We analyzed homogenized internal organs of these animals (lungs, spleen, kidneys). Of all samples from the greater mole rat, 83% were positive for tularemia antigens and 17% were positive forHFRS. None of the analyzed European moles had antigens of tularemia and HFRS. No double infection with both tularemia and hantavirus was detected in the subterranean mammals. Double infection was found among terrestrial mammals in the bank vole and the forest dormouse. Full article

Tularemia is a zoonotic disease found throughout most of the northern hemisphere that may experience range expansion with warming temperatures. Rodents and lagomorphs are reservoirs for the disease, and outbreaks of tularemia often follow peaks in their abundance. As small mammals dominate the diet of arctic foxes (Vulpes lagopus), we determined whether they may serve as sentinels by identifying antibodies in live-captured and harvested foxes from northern Canada. Overall seroprevalence was 2% (CI95 1–2%) in 176 foxes harvested in 2018–2019 compared to 17% (CI95 12–22%) of 230 foxes captured live in 2011–2021. Prevalence was at an all-time high in 2018, following a peak in vole abundance in 2017. Antibodies were identified in fox pups born in 2018 and 2019, suggesting that F. tularensis was actively transmitted during the summers. High precipitation during the summer, increased snow cover and colder temperatures in May, and a higher abundance of voles were all associated with increased seroprevalence in live-captured foxes. Thus, exposure to F. tularensis is largely mediated through climate and rodent populations in the Canadian Arctic, and arctic foxes are useful sentinels for F. tularensis in northern ecosystems. Further studies should investigate whether infection impacts arctic fox survival and reproductive success in the circumpolar North. Full article