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Kirby, James

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Kirby

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Kirby, James
Author's Publications: search.filters.isAuthorOfPublication.614405a2-99ce-4833-8243-87cf119ba9b8

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Now showing 1 - 4 of 4
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    Fatal Spontaneous Clostridium bifermentans Necrotizing Endometritis: A Case Report and Literature Review of the Pathogen
    (Oxford University Press, 2016) Hale, Andrew; Kirby, James; Albrecht, Mary
    Clostridium bifermentans is a rare pathogen in humans. A fatal case of fulminant endometritis with toxic shock and capillary leak secondary to C bifermentans infection in a young woman is described, and this is compared to all 13 previously described cases of C bifermentans infection.
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    The Alzheimer's Disease-Associated Amyloid \(\beta\)-Protein Is an Antimicrobial Peptide
    (Public Library of Science, 2010) Soscia, Stephanie; Kirby, James; Washicosky, Kevin J.; Tucker, Stephanie; Ingelsson, Martin; Hyman, Bradley; Burton, Mark A.; Duong, Scott; Tanzi, Rudolph; Moir, Robert; Goldstein, Lee E.
    Background: The amyloid \(\beta\)-protein (A\(\beta\)) is believed to be the key mediator of Alzheimer's disease (AD) pathology. A\(\beta\) is most often characterized as an incidental catabolic byproduct that lacks a normal physiological role. However, A\(\beta\) has been shown to be a specific ligand for a number of different receptors and other molecules, transported by complex trafficking pathways, modulated in response to a variety of environmental stressors, and able to induce pro-inflammatory activities. Methodology/Principal Findings: Here, we provide data supporting an in vivo function for A\(\beta\) as an antimicrobial peptide (AMP). Experiments used established in vitro assays to compare antimicrobial activities of A\(\beta\) and LL-37, an archetypical human AMP. Findings reveal that A\(\beta\) exerts antimicrobial activity against eight common and clinically relevant microorganisms with a potency equivalent to, and in some cases greater than, LL-37. Furthermore, we show that AD whole brain homogenates have significantly higher antimicrobial activity than aged matched non-AD samples and that AMP action correlates with tissue A\(\beta\) levels. Consistent with A\(\beta\)-mediated activity, the increased antimicrobial action was ablated by immunodepletion of AD brain homogenates with anti-A\(\beta\) antibodies. Conclusions/Significance: Our findings suggest A\(\beta\) is a hitherto unrecognized AMP that may normally function in the innate immune system. This finding stands in stark contrast to current models of A\(\beta\)-mediated pathology and has important implications for ongoing and future AD treatment strategies.
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    The Alzheimer’s Disease-Associated Amyloid β-Protein Is an Antimicrobial Peptide
    (Public Library of Science, 2010) Kirby, James; Washicosky, Kevin J.; Tucker, Stephanie M.; Ingelsson, Martin; Hyman, Bradley; Burton, Mark A.; Goldstein, Lee E.; Duong, Scott; Tanzi, Rudolph; Moir, Robert
    Background: The amyloid β-protein (Aβ) is believed to be the key mediator of Alzheimer's disease (AD) pathology. Aβ is most often characterized as an incidental catabolic byproduct that lacks a normal physiological role. However, Aβ has been shown to be a specific ligand for a number of different receptors and other molecules, transported by complex trafficking pathways, modulated in response to a variety of environmental stressors, and able to induce pro-inflammatory activities. Methodology/Principal Findings: Here, we provide data supporting an in vivo function for Aβ as an antimicrobial peptide (AMP). Experiments used established in vitro assays to compare antimicrobial activities of Aβ and LL-37, an archetypical human AMP. Findings reveal that Aβ exerts antimicrobial activity against eight common and clinically relevant microorganisms with a potency equivalent to, and in some cases greater than, LL-37. Furthermore, we show that AD whole brain homogenates have significantly higher antimicrobial activity than aged matched non-AD samples and that AMP action correlates with tissue Aβ levels. Consistent with Aβ-mediated activity, the increased antimicrobial action was ablated by immunodepletion of AD brain homogenates with anti-Aβ antibodies. Conclusions/Significance: Our findings suggest Aβ is a hitherto unrecognized AMP that may normally function in the innate immune system. This finding stands in stark contrast to current models of Aβ-mediated pathology and has important implications for ongoing and future AD treatment strategies.
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    Investigation of a Candida guilliermondii Pseudo-Outbreak Reveals a Novel Source of Laboratory Contamination
    (American Society for Microbiology, 2017-04) Kirby, James; Branch-Elliman, Westyn; LaSalvia, Mary; Longhi, Lorinda; MacKechnie, Matthew; Urman, Grigoriy; Baldini, Linda M.; Muriel, Fatima R.; Sullivan, Bernadette; Yassa, David; Gold, Howard; Wagner, Trevor K.; Diekema, Daniel J.; Wright, Sharon
    Candida guilliermondii was isolated from sterile specimens with increasing frequency over a several-month period despite a paucity of clinical evidence suggesting true Candida infections. However, a health care-associated outbreak was strongly considered due to growth patterns in the microbiology laboratory that were more consistent with true infection than environmental contamination. Therefore, an extensive investigation was performed to identify its cause. With the exception of one case, patient clinical courses were not consistent with true invasive fungal infections. Furthermore, no epidemiologic link between patients was identified. Rather, extensive environmental sampling revealed C. guilliermondii in an anaerobic holding jar in the clinical microbiology laboratory, where anaerobic plates were prereduced and held before inoculating specimens. C. guilliermondii grows poorly under anaerobic conditions. Thus, we postulate that anaerobic plates became intermittently contaminated. Passaging from intermittently contaminated anaerobic plates to primary quadrants of aerobic media during specimen planting yielded a colonial growth pattern typical for true specimen infection, thus obscuring laboratory contamination. A molecular evaluation of the C. guilliermondii isolates confirmed a common source for pseudo-outbreak cases but not for the one true infection. In line with Reason's model of organizational accidents, active and latent errors coincided to contribute to the pseudo-outbreak. These included organism factors (lack of growth in anaerobic conditions obscuring plate contamination), human factors (lack of strict adherence to plating order, leading to only intermittent observation of aerobic plate positivity), and laboratory factors (novel equipment). All of these variables should be considered when evaluating possible laboratory-based pseudo-outbreaks.