Genomic Markers for Differentiation of
            <i>Francisella tularensis</i>
            subsp.
            <i>tularensis</i>
            A.I and A.II Strains

Molins-Schneekloth, Claudia R.; Belisle, John T.; Petersen, Jeannine M.

doi:10.1128/aem.01522-07

Cited by 22 publications

(21 citation statements)

References 20 publications

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“…tularensis strains have been considered equivalent with respect to virulence. Molecular methods, specifically multiple locus variable number tandem repeat analysis (MLVA), pulsed field gel electrophoresis (PFGE), and genome sequence comparisons, have separated this subspecies into 2 genetically distinct clades, A1 (also known as A.I and A-east) and A2 (also known as A.II and A-west) (Beckstrom-Sternberg et al, 2007;Farlow et al, 2005;Johansson et al, 2004;Larsson et al, 2007;Molins-Schneekloth et al, 2008;Nubel et al, 2006;Staples et al, 2006;Svensson et al, 2005). Recently, a difference in the severity of human illness caused by F. tularensis subsp.…”

Section: Introductionmentioning

confidence: 99%

“…Despite this difference in clinical severity, the only methods currently available for differentiating F. tularensis subsp. tularensis clades A1 and A2 require a recovered isolate (PFGE and MLVA) or are lacking in sensitivity (conventional polymerase chain reaction [PCR] and MLVA) (Farlow et al, 2005;Molins-Schneekloth et al, 2008;Staples et al, 2006). Here, we develop and evaluate TaqMan PCR assays for the identification of F. tularensis subsp.…”

Section: Introductionmentioning

confidence: 99%

“…tularensis clades A1 and A2. Two regions of difference (RD), RD-5 and RD-3, previously identified by suppression subtractive hybridization, were used for assay development (Molins-Schneekloth et al, 2008). RD-5 lies within a region spanning both geneencoding regions (hypothetical protein and a pseudogene for methyltransferase) and an intergenic region.…”

Section: Introductionmentioning

confidence: 99%

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Identification of Francisella tularensis subsp. tularensis A1 and A2 infections by real-time polymerase chain reaction

Molins

Carlson

Coombs

et al. 2009

Diagnostic Microbiology and Infectious Disease

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Francisella tularensis subsp. tularensis (type A) is subdivided into clades A1 and A2. Human tularemia infections caused by A1 and A2 differ with respect to clinical outcome; A1 infections are associated with a higher case fatality rate. In this study, we develop and evaluate TaqMan polymerase chain reaction (PCR) assays for identification of A1 and A2. Both assays were shown to be specific to either A1 or A2, with sensitivities of 10 genomic equivalents. Real-time PCR results for identification of A1 and A2 were in complete agreement with results obtained by pulsed field gel electrophoresis analysis or conventional PCR when specimens from sporadic tularemia cases and a tularemia outbreak involving both A1 and A2 were tested. In addition, outbreak samples not previously typed to the clade level could be classified as A1 or A2. The assays described here provide new diagnostic tools with a level of sensitivity not previously available for identification of A1 and A2 infections. Published by Elsevier Inc.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Identification of Francisella tularensis subsp. tularensis A1 and A2 infections by real-time polymerase chain reaction

Molins

Carlson

Coombs

et al. 2009

Diagnostic Microbiology and Infectious Disease

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“…Type B strains have a G at nt 465 of the sdhA gene sequence, whereas type A strains have an A at this position. To further distinguish the type A samples between clade A1 or clade A2, conventional PCRs were used (13). Suffi cient F. tularensis DNA was present to type infections for 5 of the 9 type A-positive lagomorph carcasses; 4 yielded a PCR product consistent with the A1 clade (570 bp), and 1 yielded a product consistent with the A2 clade (396 bp) (Figure 2) (13).…”

Section: The Outbreakmentioning

confidence: 99%

MultipleFrancisella tularensisSubspecies and Clades, Tularemia Outbreak, Utah

Petersen¹,

Carlson²,

Dietrich³

et al. 2008

Emerg. Infect. Dis.

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In July 2007, a deer fl y-associated outbreak of tularemia occurred in Utah. Human infections were caused by 2 clades (A1 and A2) of Francisella tularensis subsp. tularensis. Lagomorph carcasses from the area yielded evidence of infection with A1 and A2, as well as F. tularensis subsp. holarctica. These fi ndings indicate that multiple subspecies and clades can cause disease in a localized outbreak of tularemia.

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“…We previously identified genomic regions of difference between the F. tularensis A1 and A2 subpopulations (33). One of these regions of genomic variance, denoted RD12, included a putative chitinase gene chiA that was present in F. tularensis A1, but not A2 genomes.…”

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confidence: 99%

Differential Chitinase Activity and Production within Francisella Species, Subspecies, and Subpopulations

et al. 2011

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Genotyping of Francisella tularensis (A1a, A1b, A2, and type B) and Francisella novicida has identified multiple differences between species and among F. tularensis subspecies and subpopulations. Variations in virulence, geographic distribution, and ecology are also known to exist among this group of bacteria, despite the >95% nucleotide identity in their genomes. This study expands the description of phenotypic differences by evaluating the ability of F. tularensis and F. novicida to degrade chitin analogs and produce active chitinases. Endochitinase activities were observed to vary among F. tularensis and F. novicida strains. The activity observed for F. tularensis strains was predominantly associated with whole-cell lysates, while the chitinase activity of F. novicida localized to the culture supernatant. In addition, the overall level of chitinase activity differed among the subpopulations of F. tularensis and between the species. Bioinformatic analyses identified two new putative chitinase genes (chiC and chiD), as well as the previously described chiA and chiB. However, the presence of these four open reading frames as intact genes or pseudogenes was found to differ between Francisella species and F. tularensis subspecies and subpopulations. Recombinant production of the putative chitinases and enzymatic evaluations revealed ChiA, ChiB, ChiC, and ChiD possessed dissimilar chitinase activities. These biochemical studies coupled with bioinformatic analyses and the evaluation of chiA and chiC knockouts in F. tularensis A1 and A2 strains, respectively, provided a molecular basis to explain the differential chitinase activities observed among the species and subpopulations of Francisella.

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Genomic Markers for Differentiation of Francisella tularensis subsp. tularensis A.I and A.II Strains

Cited by 22 publications

References 20 publications

Identification of Francisella tularensis subsp. tularensis A1 and A2 infections by real-time polymerase chain reaction

Identification of Francisella tularensis subsp. tularensis A1 and A2 infections by real-time polymerase chain reaction

MultipleFrancisella tularensisSubspecies and Clades, Tularemia Outbreak, Utah

Differential Chitinase Activity and Production within Francisella Species, Subspecies, and Subpopulations

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