Multiple<i>Francisella tularensis</i>Subspecies and Clades, Tularemia Outbreak, Utah

Petersen, Jeannine M.; Carlson, Jennifer K.; Dietrich, Gabrielle; Eisen, Rebecca J.; Coombs, Jana; Janusz, Aimee M.; Summers, J Kimberley; Beard, Charles B.; Mead, Paul S.

doi:10.3201/eid1412.080482

Cited by 34 publications

(23 citation statements)

References 13 publications

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“…Ft subspecies holarctica is found throughout the Northern hemisphere, whereas Ft subspecies tularensis is restricted to North America. Recently, type A strains of Ft were divided into 2 clades; A1 strains are located in central and eastern United States, and A2 strains are more abundant than A1 strains in the west [21,56]. Moreover, for reasons that are as-yet unclear, the casefatality rate for humans infected with A1 strains is much higher (24%) than type B (7%) or A2 (0%) isolates [57].…”

Section: Discussionmentioning

confidence: 97%

“…The highly virulent subclone Schu S4 was isolated in 1951 and has since been studied widely [20]. Schu S4 and the Massachusetts strain (MA00-2987) belong to clade A1 [23], the Wyoming strain (WY96-3418) belongs to clade A2 [21,23], and isolates from 2 patients in Iowa are type B (1547-57 and 1623-36) [24]. TI0902 is a type A strain of an unknown subtype that was isolated from a cat [22].…”

Section: Discussionmentioning

confidence: 98%

“…Bacterial strains used in this study are shown in Table 1 and include virulent Ft subspecies tularensis (type A) strains Schu S4 [20,21], TI0902 [22], MA00-2987 [23], and WY96-3418 [21,23], as well as virulent Ft subspecies holarctica (type B) strains 1547-57 [24] and 1623-36 and the attenuated type B strain LVS [25]. Ft were grown routinely on CHAB for 48 h at 37°C in 5% CO 2 .…”

Section: Cultivation Of Wt Bacteriamentioning

confidence: 99%

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Genetic redirection of T cells for cancer therapy

McCaffrey

Schwartz

Lindemann

et al. 2010

Journal of Leukocyte Biology

165

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Ft is a facultative intracellular pathogen that infects many cell types, including neutrophils. In previous work, we demonstrated that the type B Ft strain LVS disrupts NADPH oxidase activity throughout human neutrophils, but how this is achieved is incompletely defined. Here, we used several type A and type B strains to demonstrate that Ft-mediated NADPH oxidase inhibition is more complex than appreciated previously. We confirm that phagosomes containing Ft opsonized with AS exclude flavocytochrome b(558) and extend previous results to show that soluble phox proteins were also affected, as indicated by diminished phosphorylation of p47(phox) and other PKC substrates. However, a different mechanism accounts for the ability of Ft to inhibit neutrophil activation by formyl peptides, Staphylococcus aureus, OpZ, and phorbol esters. In this case, enzyme targeting and assembly were normal, and impaired superoxide production was characterized by sustained membrane accumulation of dysfunctional NADPH oxidase complexes. A similar post-assembly inhibition mechanism also diminished the ability of anti-Ft IS to confer neutrophil activation and bacterial killing, consistent with the limited role for antibodies in host defense during tularemia. Studies of mutants that we generated in the type A Ft strain Schu S4 demonstrate that the regulatory factor fevR is essential for NADPH oxidase inhibition, whereas iglI and iglJ, candidate secretion system effectors, and the acid phosphatase acpA are not. As Ft uses multiple mechanisms to block neutrophil NADPH oxidase activity, our data strongly suggest that this is a central aspect of virulence.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 98%

Section: Cultivation Of Wt Bacteriamentioning

confidence: 99%

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Genetic redirection of T cells for cancer therapy

McCaffrey

Schwartz

Lindemann

et al. 2010

Journal of Leukocyte Biology

165

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“…Type B infections have been reported across the United States, but A1 and A2 clades are typically conÞned to east or west of the Rocky Mountains, respectively, with some geographic overlap in California (Farlow et al 2005, Staples et al 2006. A recent study demonstrated that A1 strains also occur in the intermountain west and that at very local scales, A1, A2, and type B infections can circulate in the same local epizootic (Petersen et al 2008).…”

mentioning

confidence: 94%

Transmission Efficiency of Francisella tularensis by Adult American Dog Ticks (Acari: Ixodidae)

et al. 2011

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The American dog tick, Dermacentor variabilis (Say) (Acari: Ixodidae), has been implicated as a potential bridging vector to humans of Francisella tularensis, the etiological agent of tularemia. Since the initial studies evaluating vector competency of D. variabilis were conducted, F. tularensis has been subdivided into subspecies and clades that differ in their geographical distribution in the United States and in the severity of infections caused in humans. Here, we demonstrate that D. variabilis nymphs efficiently acquire, transtadially maintain, and transmit each of the strains tested (clades A1b and A2, and type B). Transmission efficiency by adult females was similarly high among infection groups and ranged from 58% for type B to 89% for A2 infections. In addition, we demonstrated that transmission can occur shortly after tick attachment. These findings support the concept that D. variabilis adults may play a significant role in epizootic transmission of F. tularensis, and as a bridging vector to humans.

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“…Indeed, in a tularemia outbreak in 2007 in North-Central Utah, a region predicted by the models, A1 strains were identified as the cause of the infections. 17 Similarly, a tularemia epizootic in lagomorphs caused by A2 strains occurred in Presidio, Jeff Davis, and Potter counties in Texas in 2006 (Centers for Disease Control, unpublished data), regions predicted by the models, but for which isolates were not included in the data set on which the models were based. Finally, although type B isolates from Michigan, Minnesota, and North Dakota were not included in the data set, the model strongly predicted distribution of type B in these areas; indeed, both human and animal infections caused by type B have previously been documented from these regions of the upper Midwest.…”

Section: Discussionmentioning

confidence: 99%

Ecological Niche Modeling of Francisella tularensis Subspecies and Clades in the United States

Nakazawa¹,

Williams²,

Peterson³

et al. 2010

The American Society of Tropical Medicine and Hygiene

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Two subspecies of Francisella tularensis are recognized: F. tularensis subsp. tularensis (type A) and F. tularensis subsp. holartica (type B). Type A has been subdivided further into A1a, A1b, and A2, which differ geographically and clinically. The aim of this work was to determine whether or not differences among subspecies and clades translate into distinct ecological niches. We used 223 isolates from humans and wildlife representing all six genotypes (type A, B, A1, A2, A1a, or A1b). Ecological-niche models were built independently for each genotype, using the genetic algorithm for rule-set prediction. The resulting models were compared using a non-parametric multivariate analysis-of-variance method. A1 and A2 are ecologically distinct, supporting the previously observed geographic division, whereas ecological niches for types A and B overlapped notably but A1a and A1b displayed no appreciable differences in their ecological niches.

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MultipleFrancisella tularensisSubspecies and Clades, Tularemia Outbreak, Utah

Cited by 34 publications

References 13 publications

Genetic redirection of T cells for cancer therapy

Genetic redirection of T cells for cancer therapy

Transmission Efficiency of Francisella tularensis by Adult American Dog Ticks (Acari: Ixodidae)

Ecological Niche Modeling of Francisella tularensis Subspecies and Clades in the United States

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