Tularemia cases increase in the USA from 2011 through 2019

Bishop, Alexandra; Wang, Hsiao‐Hsuan; Donaldson, Taylor G.; Brockinton, Emily E.; Kothapalli, Esha; Clark, Scott; Vishwanath, Tanvi; Canales, Tatyana; Sreekumar, Krishnendu; Grant, William E.; Teel, Pete D.

doi:10.1016/j.crpvbd.2023.100116

Cited by 13 publications

(9 citation statements)

References 36 publications

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“…Francisella tularensis is an intracellular pathogen that is endemic throughout much of the northern hemisphere and is the causative agent of tularaemia [1, 2]. While only a few hundred cases occur per year in humans in the USA [3], tularaemia can be life-threatening if left untreated [4]. Two Francisella subspecies are almost exclusively responsible for causing illness in humans: F. tularensis subsp.…”

Section: Introductionmentioning

confidence: 99%

Mutation of wbtJ, a N-formyltransferase involved in O-antigen synthesis, results in biofilm formation, phase variation and attenuation in Francisella tularensis

Mlynek,

Toothman,

Martinez

et al. 2024

Microbiology

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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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Section: Introductionmentioning

confidence: 99%

Mutation of wbtJ, a N-formyltransferase involved in O-antigen synthesis, results in biofilm formation, phase variation and attenuation in Francisella tularensis

Mlynek,

Toothman,

Martinez

et al. 2024

Microbiology

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“…McCoy and Chapin described for the first time in 1911 a disease comparable to plague in ground squirrels in Tulare County, California. Afterwards, Edward Francis observed that F. tularensis was the source of multiple clinical syndromes in humans and suggested the term "tularemia" to characterize the condition ( 1 , 2 ).…”

Section: Introductionmentioning

confidence: 99%

Characterization of tularemia foci in the Republic of Kazakhstan from 2000 to 2020

Izbanova,

Lukhnova,

Sadovskaya

et al. 2024

Front. Epidemiol.

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The wide distribution of tularemia in the territory of Kazakhstan is associated with landscape and geographical characteristics. This is explained by a combination of natural factors: the presence of certain types of rodents—reservoirs and sources, ectoparasites—carriers of the causative agent of tularemia. The study of the current spatial and temporal characterization of tularemia in Kazakhstan from 2000 to 2020 will determine the epidemiological status of tularemia and improve the monitoring system in Kazakhstan. In this work we demonstrated the results of a retrospective survey of natural foci of tularemia: analysis of vector, small mammal and human data. The spatial and temporal characteristics of tularemia from 2000 to 2020 in the territory of Kazakhstan were studied in comparison with historical data, including the description of tularemia outbreaks, the clinical picture, and the source of infection, transmission factors, and geographical coordinates of outbreak registration. Sampling was carried out by trapping rodents on snap traps and collecting ticks by rodent combing and by "flagging" methods. For the last 20 years, 85 human cases of tularemia have been reported. During the period from 2000 to 2020, more than 600 strains of F. tularensis were isolated from field rodents and ticks in the natural foci of tularemia. MLVA typing of F. tularensis strains isolated from natural foci of tularemia in Kazakhstan over the past 20 years. The results of retrospective monitoring indicate that currently active foci of tularemia include the Aktobe, West Kazakhstan, Almaty, East Kazakhstan, and Pavlodar regions. Low-activity natural foci are located in the territory of the Akmola, Karaganda, North Kazakhstan, Kostanay, Atyrau, Zhambyl, and Kyzylorda regions. There are no active natural foci of tularemia in the Mangystau and Turkestan regions. The widespread occurrence of tularemia in the country is associated with landscape and geographical features that contribute to the circulation of the pathogen in the natural focus. An analysis of natural foci of tularemia showed that it is necessary to continue monitoring studies of carriers and vectors for the presence of the causative agent of the F. tularensis, in order to prevent mass cases of human disease.

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“…The European Center for Disease Control and Prevention (ECDC) reported 641 confirmed human tularemia cases in Europe in 2020 (incidence, 0.15 per 100,000 persons per year), most of which occurred in Sweden and Finland. In the USA, 1984 human tularemia cases were reported from 2011 to 2019 (average incidence, 0.07 cases per 100,000 person per year), predominantly in Arkansas, Missouri, Oklahoma, and Kansas ( Bishop et al, 2023 ). Tularemia is a significant public health problem since the 2000’s in Turkey ( Erdem et al, 2014 ).…”

Section: Introductionmentioning

confidence: 99%

Tularemia treatment: experimental and clinical data

Maurin,

Pondérand,

Hennebique

et al. 2024

Front. Microbiol.

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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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Tularemia cases increase in the USA from 2011 through 2019

Cited by 13 publications

References 36 publications

Mutation of wbtJ, a N-formyltransferase involved in O-antigen synthesis, results in biofilm formation, phase variation and attenuation in Francisella tularensis

Mutation of wbtJ, a N-formyltransferase involved in O-antigen synthesis, results in biofilm formation, phase variation and attenuation in Francisella tularensis

Characterization of tularemia foci in the Republic of Kazakhstan from 2000 to 2020

Tularemia treatment: experimental and clinical data

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