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Wakade RS, Wellington M, Krysan DJ. Temporal dynamics of Candida albicans morphogenesis and gene expression reveals distinctions between in vitro and in vivo filamentation. mSphere 2024; 9:e0011024. [PMID: 38501830 PMCID: PMC11036811 DOI: 10.1128/msphere.00110-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 02/29/2024] [Indexed: 03/20/2024] Open
Abstract
Candida albicans is a common human fungal pathogen that is also a commensal of the oral cavity and gastrointestinal tract. C. albicans pathogenesis is linked to its transition from budding yeast to filamentous morphologies including hyphae and pseudohyphae. The centrality of this virulence trait to C. albicans pathobiology has resulted in extensive characterization of a wide range of factors associated with filamentation with a strong focus on transcriptional regulation. The vast majority of these experiments have used in vitro conditions to induce the yeast-to-filament transition. Taking advantage of in vivo approaches to quantitatively characterize both morphology and gene expression during filamentation during mammalian infection, we have investigated the dynamics of these two aspects of filamentation in vivo and compared them to in vitro filament induction with "host-like" tissue culture media supplemented with serum at mammalian body temperature. Although filamentation shares many common features in the two conditions, we have found two significant differences. First, alternative carbon metabolism genes are expressed early during in vitro filamentation and late in vivo, suggesting significant differences in glucose availability. Second, C. albicans begins a hyphae-to-yeast transition after 4-h incubation while we find little evidence of hyphae-to-yeast transition in vivo up to 24 h post-infection. We show that the low rate of in vivo hyphae-to-yeast transition is likely due to the very low expression of PES1, a key driver of lateral yeast in vitro and that heterologous expression of PES1 is sufficient to trigger lateral yeast formation in vivo.IMPORTANCECandida albicans filamentation is correlated with virulence and is an intensively studied aspect of C. albicans biology. The vast majority of studies on C. albicans filamentation are based on in vitro induction of hyphae and pseudohyphae. Here we used an in vivo filamentation assay and in vivo expression profiling to compare the tempo of morphogenesis and gene expression between in vitro and in vivo filamentation. Although the hyphal gene expression profile is induced rapidly in both conditions, it remains stably expressed over a 12-h time course in vivo while it peaks after 4 h in vitro and is reduced. This reduced hyphal gene expression in vitro correlates with reduced hyphae and increased hyphae-to-yeast transition. By contrast, there is little evidence of hyphae-to-yeast transition in vivo.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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2
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Harrington EM, Trautman K, Davis MB, Varzavand K, Meacham H, Dains A, Marra AR, McDanel J, Kenne L, Hanna B, Murphy JP, Diekema DJ, Wellington M, Brust KB, Kobayashi T, Abosi OJ. Descriptive epidemiology of central line-associated bloodstream infections at an academic medical center in Iowa, 2019-2022. Am J Infect Control 2024; 52:436-442. [PMID: 37827243 DOI: 10.1016/j.ajic.2023.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023]
Abstract
BACKGROUND Central line-associated bloodstream infections (CLABSIs) increased nationally during the COVID-19 pandemic. We described CLABSIs at our institution during 2019 to 2022. METHODS This retrospective observational study examined CLABSIs among adult inpatients at an 866-bed teaching hospital in the Midwest. CLABSI incidence was trended over time and compared to monthly COVID-19 admissions. Manual chart review was performed to obtain patient demographics, catheter-associated variables, pathogens, and clinical outcomes. RESULTS We identified 178 CLABSIs. The CLABSI incidence (cases per 1,000 line days) tripled in October 2020 as COVID-19 admissions increased. CLABSIs in 2020 were more frequently caused by coagulase-negative staphylococci and more frequently occurred in the intensive care units 7+ days after central line insertion. The CLABSI incidence normalized in early 2021 and did not increase during subsequent COVID-19 surges. Throughout 2019 to 2022, about half of the nontunneled central venous catheters involved in CLABSI were placed emergently. One-quarter of CLABSIs involved multiple central lines. Chlorhexidine skin treatment adherence was limited by patient refusal. CONCLUSIONS The increase in CLABSIs in late 2020 during a surge in COVID-19 admissions was likely related to central line maintenance but has resolved. Characterizing CLABSI cases can provide insight into adherence to guideline-recommended prevention practices and identify areas for improvement at individual institutions.
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Affiliation(s)
- Elaine M Harrington
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA.
| | - Kathryn Trautman
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Mary B Davis
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kristin Varzavand
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Holly Meacham
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Angelique Dains
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Alexandre R Marra
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA; Faculdade Israelita de Ciências da Saúde Albert Einstein, Hospital Israelita Albert Einstein, São Paulo, Brazil
| | - Jennifer McDanel
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Lynnette Kenne
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Beth Hanna
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Jaime P Murphy
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Daniel J Diekema
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Melanie Wellington
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Karen B Brust
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Takaaki Kobayashi
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Oluchi J Abosi
- Quality Improvement Program, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
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Wakade RS, Wellington M, Krysan DJ. The role of the C. albicans transcriptional repressor NRG1 during filamentation and disseminated candidiasis is strain dependent. mSphere 2024; 9:e0078523. [PMID: 38376205 PMCID: PMC10964420 DOI: 10.1128/msphere.00785-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024] Open
Abstract
Candida albicans is one of the most common causes of superficial and invasive fungal diseases in humans. Its ability to cause disease is closely linked to its ability to undergo a morphological transition from budding yeast to filamentous forms (hyphae and pseudohyphae). The extent to which C. albicans strains isolated from patients undergo filamentation varies significantly. In addition, the filamentation phenotypes of mutants involving transcription factors that positively regulate hyphal morphogenesis can also vary from strain to strain. Here, we characterized the virulence, in vitro and in vivo filamentation, and in vitro and in vivo hypha-associated gene expression profiles for four poorly filamenting C. albicans isolates and their corresponding deletion mutants of the repressor of filamentation NRG1. The two most virulent strains, 57055 and 78048, show robust in vivo filamentation but are predominately yeast phase under in vitro hypha induction; the two low-virulence strains (94015 and 78042) do not undergo filamentation well under either condition. In vitro, deletion of NRG1 increases hyphae formation in the SC5314 derivative SN250, but only pseudohyphae are formed in the clinical isolates. Deletion of NRG1 modestly increased the virulence of 78042, which was accompanied by increased expression of hypha-associated genes without an increase in filamentation. Strikingly, deletion of NRG1 in 78048 reduced filamentation in vivo, expression of candidalysin (ECE1), and virulence without dramatically altering establishment of infection. Thus, the function of the conserved repressor NRG1 in C. albicans shows strain-based heterogeneity during infection.IMPORTANCEClinical isolates of the human fungal pathogen Candida albicans show significant variation in their ability to undergo in vitro filamentation and in the function of well-characterized transcriptional regulators of filamentation. Here, we show that Nrg1, a key repressor of filamentation and filament specific gene expression in standard reference strains, has strain-dependent functions, particularly during infection. Most strikingly, loss of NRG1 function can reduce filamentation, hypha-specific gene expression such as the toxin candidalysin, and virulence in some strains. Our data emphasize that the functions of seemingly fundamental and well-conserved transcriptional regulators such as Nrg1 are contextual with respect to both environment and genetic backgrounds.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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4
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Nielson JA, Jezewski AJ, Wellington M, Davis JM. Survival in macrophages induces enhanced virulence in Cryptococcus. mSphere 2024; 9:e0050423. [PMID: 38073033 PMCID: PMC10826345 DOI: 10.1128/msphere.00504-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/31/2023] [Indexed: 01/31/2024] Open
Abstract
Cryptococcus is a ubiquitous environmental fungus and frequent colonizer of human lungs. Colonization can lead to diverse outcomes, from clearance to long-term colonization to life-threatening meningoencephalitis. Regardless of the outcome, the process starts with an encounter with phagocytes. Using the zebrafish model of this infection, we have noted that cryptococcal cells first spend time inside macrophages before they become capable of pathogenic replication and dissemination. What "licensing" process takes place during this initial encounter, and how are licensed cryptococcal cells different? To address this, we isolated cryptococcal cells after phagocytosis by cultured macrophages and found these macrophage-experienced cells to be markedly more virulent in both zebrafish and mouse models. Despite producing a thick polysaccharide capsule, they were still subject to phagocytosis by macrophages in the zebrafish. Analysis of antigenic cell wall components in these licensed cells demonstrated that components of mannose and chitin are more available for staining than they are in culture-grown cells or cells with capsule production induced in vitro. Cryptococcus is capable of exiting or transferring between macrophages in vitro, raising the likelihood that this fungus alternates between intracellular and extracellular life during growth in the lungs. Our results raise the possibility that intracellular life has its advantages over time, and phagocytosis-induced alteration in mannose and chitin exposure is one way that makes subsequent rounds of phagocytosis more beneficial to the fungus.IMPORTANCECryptococcosis begins in the lungs and can ultimately travel through the bloodstream to cause devastating infection in the central nervous system. In the zebrafish model, small amounts of cryptococcus inoculated into the bloodstream are initially phagocytosed and become far more capable of dissemination after they exit macrophages. Similarly, survival in the mouse lung produces cryptococcal cell types with enhanced dissemination. In this study, we have evaluated how phagocytosis changes the properties of Cryptococcus during pathogenesis. Macrophage-experienced cells (MECs) become "licensed" for enhanced virulence. They out-disseminate culture-grown cells in the fish and out-compete non-MECs in the mouse lung. Analysis of their cell surface demonstrates that MECs have increased availability of cell wall components mannose and chitin substances involved in provoking phagocytosis. These findings suggest how Cryptococcus might tune its cell surface to induce but survive repeated phagocytosis during early pathogenesis in the lung.
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Affiliation(s)
- Jacquelyn A. Nielson
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Andrew J. Jezewski
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Melanie Wellington
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - J. Muse Davis
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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5
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Abosi OJ, Trannel A, Schwartzhoff P, Ackman M, Zilles B, Marra AR, Dains A, Naito T, Salinas JL, Diekema DJ, Hanna B, Murphy JP, Wellington M, Brust K, Kobayashi T. A review of extended coronavirus disease 2019 (COVID-19) isolation duration among inpatients in a tertiary-care hospital-Iowa, 2020-2022. Infect Control Hosp Epidemiol 2024; 45:110-113. [PMID: 37528757 PMCID: PMC10782192 DOI: 10.1017/ice.2023.154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/26/2023] [Accepted: 06/18/2023] [Indexed: 08/03/2023]
Abstract
Of the 2,668 patients admitted with coronavirus disease 2019 (COVID-19), 4% underwent prolonged isolation for >20 days. Reasons for extended isolation were inconsistent with Centers for Disease Control and Prevention (CDC) guidelines in 25% of these patients and were questionable in 54% due to an ongoing critically ill condition at day 20 without CDC-defined immunocompromised status.
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Affiliation(s)
- Oluchi J. Abosi
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Alexandra Trannel
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | | | - Mark Ackman
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Barbara Zilles
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Alexandre R. Marra
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
- Hospital Israelita Albert Einstein, São Paulo, Brazil
| | - Angelique Dains
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Toshio Naito
- General Medicine, Juntendo University Hospital, Tokyo, Japan
| | | | - Daniel J. Diekema
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Beth Hanna
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Jaime P. Murphy
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | | | - Karen Brust
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Takaaki Kobayashi
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
- General Medicine, Juntendo University Hospital, Tokyo, Japan
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6
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Wakade RS, Wellington M, Krysan DJ. The role of the C. albicans transcriptional repressor NRG1 during filamentation and disseminated candidiasis is strain-dependent. bioRxiv 2023:2023.12.15.571891. [PMID: 38168187 PMCID: PMC10760072 DOI: 10.1101/2023.12.15.571891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Candida albicans is one of the most common causes of superficial and invasive fungal disease in humans. Its ability to cause disease has been closely linked to its ability to undergo a morphological transition from budding yeast to filamentous forms (hyphae and pseudohyphae). The ability of C. albicans strains isolated from patients to undergo filamentation varies significantly. In addition, the filamentation phenotypes of mutants involving transcription factors that positively regulate hyphal morphogenesis can also vary from strain to strain. Here, we characterized the virulence, in vitro and in vivo filamentation, and in vitro and in vivo hypha-associated gene expression profiles of four poorly filamenting C. albicans isolates and their corresponding deletion mutants of the repressor of filamentation NRG1. The two most virulent strains, 57055 and 78048, show robust in vivo filamentation while remaining predominately yeast phase exposed to RPMI+10% bovine calf serum at 37°C; the two low virulence strains (94015 and 78042) do not filament well under either condition. Deletion of NRG1 increases hyphae formation in the SC5314 derivative SN250 but only pseudohyphae are formed in the clinical isolates in vivo. Deletion of NRG1 modestly increased the virulence of 78042 which was accompanied by increased expression of hyphae-associated genes without an increase in filamentation. Strikingly, deletion of NRG1 in 78048 reduced filamentation, expression of candidalysin (ECE1) and virulence in vivo without dramatically altering establishment of infection. Thus, the function of NRG1 varies significantly within this set of C. albicans isolates and can actually suppress filamentation in vivo.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City IA
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7
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Glazier VE, Kramara J, Ollinger T, Solis NV, Zarnowski R, Wakade RS, Kim MJ, Weigel GJ, Liang SH, Bennett RJ, Wellington M, Andes DR, Stamnes MA, Filler SG, Krysan DJ. The Candida albicans reference strain SC5314 contains a rare, dominant allele of the transcription factor Rob1 that modulates filamentation, biofilm formation, and oral commensalism. mBio 2023; 14:e0152123. [PMID: 37737633 PMCID: PMC10653842 DOI: 10.1128/mbio.01521-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 07/27/2023] [Indexed: 09/23/2023] Open
Abstract
IMPORTANCE Candida albicans is a commensal fungus that colonizes the human oral cavity and gastrointestinal tract but also causes mucosal as well as invasive disease. The expression of virulence traits in C. albicans clinical isolates is heterogeneous and the genetic basis of this heterogeneity is of high interest. The C. albicans reference strain SC5314 is highly invasive and expresses robust filamentation and biofilm formation relative to many other clinical isolates. Here, we show that SC5314 derivatives are heterozygous for the transcription factor Rob1 and contain an allele with a rare gain-of-function SNP that drives filamentation, biofilm formation, and virulence in a model of oropharyngeal candidiasis. These findings explain, in part, the outlier phenotype of the reference strain and highlight the role heterozygosity plays in the strain-to-strain variation of diploid fungal pathogens.
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Affiliation(s)
| | - Juraj Kramara
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Tomye Ollinger
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Norma V. Solis
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute and Harbor-UCLA Medical Center, Torrance, California, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Robert Zarnowski
- Department of Medicine, Section of Infectious Disease, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Min-Ju Kim
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Gabriel J. Weigel
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Shen-Huan Liang
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
| | - Richard J. Bennett
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - David R. Andes
- Department of Medicine, Section of Infectious Disease, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Mark A. Stamnes
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Scott G. Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute and Harbor-UCLA Medical Center, Torrance, California, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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8
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Kobayashi T, Heinemann J, Trannel A, Marra AR, Alsuhaibani M, Etienne W, Sheeler LL, Abosi O, Holley S, Kukla MB, Dains A, Jenn KE, Meacham H, Hanna B, Ford B, Brust K, Wellington M, Hartley PG, Diekema DJ, Salinas JL. Coronavirus disease 2019 (COVID-19) among nonphysician healthcare personnel by work location at a tertiary-care center, Iowa, 2020-2021. Infect Control Hosp Epidemiol 2023; 44:1351-1354. [PMID: 35652600 PMCID: PMC9203358 DOI: 10.1017/ice.2022.148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 05/09/2022] [Accepted: 05/20/2022] [Indexed: 11/27/2022]
Abstract
We describe COVID-19 cases among nonphysician healthcare personnel (HCP) by work location. The proportion of HCP with coronavirus disease 2019 (COVID-19) was highest in the emergency department and lowest among those working remotely. COVID-19 and non-COVID-19 units had similar proportions of HCP with COVID-19 (13%). Cases decreased across all work locations following COVID-19 vaccination.
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Affiliation(s)
- Takaaki Kobayashi
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - John Heinemann
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Alexandra Trannel
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Alexandre R. Marra
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
- Instituto Israelita de Ensino e Pesquisa Albert Einstein, Hospital Israelita Albert Einstein, São Paulo, Brazil
| | | | - William Etienne
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | | | - Oluchi Abosi
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Stephanie Holley
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Mary Beth Kukla
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Angelique Dains
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Kyle E. Jenn
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Holly Meacham
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Beth Hanna
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Bradley Ford
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Karen Brust
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | | | | | - Daniel J. Diekema
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
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9
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Glazier VE, Kramara J, Ollinger T, Solis NV, Zarnowski R, Wakade RS, Kim MJ, Weigel GJ, Liang SH, Bennett RJ, Wellington M, Andes DR, Stamnes MA, Filler SG, Krysan DJ. The Candida albicans reference strain SC5314 contains a rare, dominant allele of the transcription factor Rob1 that modulates biofilm formation and oral commensalism. bioRxiv 2023:2023.06.17.545405. [PMID: 37398495 PMCID: PMC10312810 DOI: 10.1101/2023.06.17.545405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Candida albicans is a diploid human fungal pathogen that displays significant genomic and phenotypic heterogeneity over a range of virulence traits and in the context of a variety of environmental niches. Here, we show that the effects of Rob1 on biofilm and filamentation virulence traits is dependent on both the specific environmental condition and the clinical strain of C. albicans . The C. albicans reference strain SC5314 is a ROB1 heterozygote with two alleles that differ by a single nucleotide polymorphism at position 946 resulting in a serine or proline containing isoform. An analysis of 224 sequenced C. albicans genomes indicates that SC5314 is the only ROB1 heterozygote documented to date and that the dominant allele contains a proline at position 946. Remarkably, the ROB1 alleles are functionally distinct and the rare ROB1 946S allele supports increased filamentation in vitro and increased biofilm formation in vitro and in vivo, suggesting it is a phenotypic gain-of-function allele. SC5314 is amongst the most highly filamentous and invasive strains characterized to date. Introduction of the ROB1 946S allele into a poorly filamenting clinical isolate increases filamentation and conversion of an SC5314 laboratory strain to a ROB1 946S homozygote increases in vitro filamentation and biofilm formation. In a mouse model of oropharyngeal infection, the predominant ROB1 946P allele establishes a commensal state while the ROB1 946S phenocopies the parent strain and invades into the mucosae. These observations provide an explanation for the distinct phenotypes of SC5314 and highlight the role of heterozygosity as a driver of C. albicans phenotypic heterogeneity. Importance Candida albicans is a commensal fungus that colonizes human oral cavity and gastrointestinal tracts but also causes mucosal as well as invasive disease. The expression of virulence traits in C. albicans clinical isolates is heterogenous and the genetic basis of this heterogeneity is of high interest. The C. albicans reference strain SC5314 is highly invasive and expresses robust filamentation and biofilm formation relative to many other clinical isolates. Here, we show that SC5314 derivatives are heterozygous for the transcription factor Rob1 and contain an allele with a rare gain-of-function SNP that drives filamentation, biofilm formation, and virulence in a model of oropharyngeal candidiasis. These finding explain, in part, the outlier phenotype of the reference strain and highlight the role of heterozygosity plays in the strain-to-strain variation of diploid fungal pathogens.
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Affiliation(s)
| | - Juraj Kramara
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Tomye Ollinger
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Norma V. Solis
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute and Harbor-UCLA Medical Center, Torrance, CA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Robert Zarnowski
- Department of Medicine, Section of Infectious Disease, University of Wisconsin, Madison WI
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison WI
| | - Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Min-Ju Kim
- Department of Microbiology, University of Georgia, Athens, GA
| | - Gabriel J. Weigel
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Shen-Huan Liang
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI
| | - Richard J. Bennett
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - David R. Andes
- Department of Medicine, Section of Infectious Disease, University of Wisconsin, Madison WI
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison WI
| | - Mark A. Stamnes
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Scott G. Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute and Harbor-UCLA Medical Center, Torrance, CA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City IA
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10
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Wakade RS, Ristow LC, Wellington M, Krysan DJ. Intravital imaging-based genetic screen reveals the transcriptional network governing Candida albicans filamentation during mammalian infection. eLife 2023; 12:e85114. [PMID: 36847358 PMCID: PMC9995110 DOI: 10.7554/elife.85114] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/26/2023] [Indexed: 03/01/2023] Open
Abstract
Candida albicans is one of the most common human fungal pathogens. C. albicans pathogenesis is tightly linked to its ability to under a morphogenetic transition from typically budding yeast to filamentous forms of hyphae and pseudohyphae. Filamentous morphogenesis is the most intensively studied C. albicans virulence traits; however, nearly all of these studies have been based on in vitro induction of filamentation. Using an intravital imaging assay of filamentation during mammalian (mouse) infection, we have screened a library of transcription factor mutants to identify those that modulate both the initiation and maintenance of filamentation in vivo. We coupled this initial screen with genetic interaction analysis and in vivo transcription profiling to characterize the transcription factor network governing filamentation in infected mammalian tissue. Three core positive (Efg1, Brg1, and Rob1) and two core negative regulators (Nrg1 and Tup1) of filament initiation were identified. No previous systematic analysis of genes affecting the elongation step has been reported and we found that large set of transcription factors affect filament elongation in vivo including four (Hms1, Lys14, War1, Dal81) with no effect on in vitro elongation. We also show that the gene targets of initiation and elongation regulators are distinct. Genetic interaction analysis of the core positive and negative regulators revealed that the master regulator Efg1 primarily functions to mediate relief of Nrg1 repression and is dispensable for expression of hypha-associated genes in vitro and in vivo. Thus, our analysis not only provide the first characterization of the transcriptional network governing C. albicans filamentation in vivo but also revealed a fundamentally new mode of function for Efg1, one of the most widely studied C. albicans transcription factors.
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Affiliation(s)
- Rohan S Wakade
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa CityUnited States
| | - Laura C Ristow
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa CityUnited States
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa CityUnited States
| | - Damian J Krysan
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa CityUnited States
- Departments of Microbiology and Immunology, Carver College of Medicine, University of IowaIowa CityUnited States
- Molecular Physiology and Biophysics, Carver College of Medicine, University of IowaIowa CityUnited States
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11
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Gelli A, Nobile CJ, Pericolini E, Wellington M. Editorial: Women in fungal pathogenesis 2021. Front Cell Infect Microbiol 2022; 12:1068446. [PMID: 36405971 PMCID: PMC9672804 DOI: 10.3389/fcimb.2022.1068446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022] Open
Affiliation(s)
- Angie Gelli
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
- *Correspondence: Angie Gelli,
| | - Clarissa J. Nobile
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, Merced, CA, United States
- Health Sciences Research Institute, University of California, Merced, Merced, CA, United States
| | - Eva Pericolini
- Department of Surgical, Medical, Dental and Morphological Sciences with Interest in Transplant, Oncological and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
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12
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Wakade RS, Krysan DJ, Wellington M. Use of <em>In Vivo</em> Imaging to Screen for Morphogenesis Phenotypes in <em>Candida albicans</em> Mutant Strains During Active Infection in a Mammalian Host. J Vis Exp 2022. [DOI: 10.3791/64258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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13
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Beattie SR, Jezewski AJ, Ristow LC, Wellington M, Krysan DJ. FKS1 Is Required for Cryptococcus neoformans Fitness In Vivo: Application of Copper-Regulated Gene Expression to Mouse Models of Cryptococcosis. mSphere 2022; 7:e0016322. [PMID: 35506343 PMCID: PMC9241531 DOI: 10.1128/msphere.00163-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 04/15/2022] [Indexed: 11/20/2022] Open
Abstract
There is an urgent need for new antifungals to treat cryptococcal meningoencephalitis, a leading cause of mortality in people living with HIV/AIDS. An important aspect of antifungal drug development is the validation of targets to determine whether they are required for the survival of the organism in animal models of disease. In Cryptococcus neoformans, a copper-regulated promoter (pCTR4-2) has been used previously to modulate gene expression in vivo. The premise for these experiments is that copper concentrations differ depending on the host niche. Here, we directly test this premise and confirm that the expression of CTR4, the promoter used to regulate gene expression, is much lower in the mouse lung compared to the brain. To further explore this approach, we applied it to the gene encoding 1,3-β-glucan synthase, FKS1. In vitro, reduced expression of FKS1 has little effect on growth but does activate the cell wall integrity stress response and increase susceptibility to caspofungin, a direct inhibitor of Fks1. These data suggest that compensatory pathways that reduce C. neoformans resistance do so through posttranscriptional effects. In vivo, however, a less pronounced reduction in FKS1 expression leads to a much more significant reduction in lung fungal burden (~1 log10 CFU), indicating that the compensatory responses to a reduction in FKS1 expression are not as effective in vivo as they are in vitro. In summary, use of copper-regulated expression of putative drug targets in vitro and in vivo can provide insights into the biological consequences of reduced activity of the target during infection. IMPORTANCE Conditional expression systems are widely used to genetically validate antifungal drug targets in mouse models of infection. Copper-regulated expression using the promoter of the CTR4 gene has been sporadically used for this purpose in C. neoformans. Here, we show that CTR4 expression is low in the lung and high in the brain, establishing the basic premise behind this approach. We applied the approach to the study of FKS1, the gene encoding the target of the echinocandin class of 1,3-β-glucan synthase inhibitors. Our in vitro and in vivo studies indicate that C. neoformans tolerates extremely low levels of FKS1 expression. This observation provides a potential explanation for the poor activity of 1,3-β-glucan synthase inhibitors toward C. neoformans.
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Affiliation(s)
- Sarah R. Beattie
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Andrew J. Jezewski
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Laura C. Ristow
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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14
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Kovoor E, Kobayashi T, Sheeler LL, Trannel A, Etienne W, Abosi O, Holley S, Dains A, Jenn KE, Meacham H, Hanna B, Marra AR, Parsons M, Ford B, Wellington M, Diekema DJ, Salinas JL. Blood culture practices in patients with a central line at an academic medical center-Iowa, 2020. Antimicrob Steward Healthc Epidemiol 2022; 2:e64. [PMID: 36483395 PMCID: PMC9726581 DOI: 10.1017/ash.2022.45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 06/17/2023]
Abstract
We analyzed blood-culture practices to characterize the utilization of the Infectious Diseases Society of America (IDSA) recommendations related to catheter-related bloodstream infection (CRBSI) blood cultures. Most patients with a central line had only peripheral blood cultures. Increasing the utilization of CRBSI guidelines may improve clinical care, but may also affect other quality metrics.
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Affiliation(s)
- Elias Kovoor
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Takaaki Kobayashi
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | | | - Alexandra Trannel
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - William Etienne
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Oluchi Abosi
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Stephanie Holley
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Angelique Dains
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Kyle E. Jenn
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Holly Meacham
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Beth Hanna
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Alexandre R. Marra
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
- Instituto Israelita de Ensino e Pesquisa Albert Einstein, Hospital Israelita Albert Einstein, São Paulo, Brazil
| | - Meredith Parsons
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Bradley Ford
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | | | - Daniel J. Diekema
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
| | - Jorge L. Salinas
- University of Iowa Hospitals & Clinics, Iowa City, Iowa, United States
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15
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Alsuhaibani M, Kobayashi T, McPherson C, Holley S, Marra AR, Trannel A, Dains A, Abosi OJ, Jenn KE, Meacham H, Sheeler L, Etienne W, Kukla ME, Wellington M, Edmond MB, Diekema DJ, Salinas JL. Impact of COVID-19 on an infection prevention and control program, Iowa 2020-2021. Am J Infect Control 2022; 50:277-282. [PMID: 35000801 PMCID: PMC8731683 DOI: 10.1016/j.ajic.2021.11.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 01/15/2023]
Abstract
Background The COVID-19 pandemic has affected infection prevention and control (IPC) programs worldwide. We evaluated the impact of COVID-19 on the University of Iowa Hospitals & Clinics IPC program by measuring the volume of calls to the program, changes in healthcare-associated infection rates, and team member perceptions. Methods We retrieved the IPC call log and healthcare-associated infection trends for 2018-2020. We defined 2 periods: pre-COVID-19 (2018-2019) and COVID-19 (January-December 2020). We also conducted one-on-one interviews and focus group interviews with members of the IPC program and describe changes in their working conditions during the COVID-19 period. Results A total of 6,564 calls were recorded during 2018-2020. The pre-COVID-19 period had a median of 71 calls and/or month (range: 50-119). During the COVID-19 period, the median call volume increased to 368/month (range: 149-829), and most calls were related to isolation precautions (50%). During the COVID-19 period, the central line-associated bloodstream infection incidence increased significantly. Infection preventionists reported that the ambiguity and conflicting guidance during the pandemic were major challenges. Conclusions Our IPC program experienced a 500% increase in consultation requests. Planning for future bio-emergencies should include creative strategies to increase response capacity within IPC programs.
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Affiliation(s)
- Mohammed Alsuhaibani
- University of Iowa Hospitals & Clinics, Iowa City, IA, USA; Department of Pediatrics, College of Medicine, Qassim University, Qassim, Saudi Arabia.
| | | | - Chad McPherson
- University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | | | - Alexandre R Marra
- University of Iowa Hospitals & Clinics, Iowa City, IA, USA; Instituto Israelita de Ensino e Pesquisa Albert Einstein, Hospital Israelita Albert Einstein, São Paulo, Brazil
| | | | | | - Oluchi J Abosi
- University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kyle E Jenn
- University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Holly Meacham
- University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | | | | | - Mary E Kukla
- University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | | | - Michael B Edmond
- Department of Medicine, West Virginia University School of Medicine, Morgantown, WV, USA
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16
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Abosi OJ, Kobayashi T, Holley S, Kukla ME, Dains A, Alsuhaibani M, Marra AR, Jenn KE, Meacham H, Sheeler LL, Etienne W, Trannel A, Garringer J, Millard W, Diekema DJ, Edmond MB, Wellington M, Salinas JL. Stable Clostridioides difficile infection rates after the discontinuation of ultraviolet light for terminal disinfection at a tertiary care center, Iowa 2019-2020. Am J Infect Control 2021; 49:1567-1568. [PMID: 34400244 DOI: 10.1016/j.ajic.2021.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/06/2021] [Accepted: 08/07/2021] [Indexed: 10/20/2022]
Abstract
We compared the incidence of Clostridioides difficile infection before and after the discontinuation of Ultraviolet light used in addition to bleach in terminal disinfection of hospital rooms. We found no difference in C. difficile infection rates but found a decreased turn over time. The benefit of Ultraviolet light may be diminished in hospitals with a high thoroughness of manual cleaning.
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17
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Kobayashi T, Ortiz ME, Imborek KL, Alsuhaibani M, Holley SA, Trannel A, Marra AR, Etienne W, Jenn KE, Abosi OJ, Meacham H, Sheeler LL, Dains A, Kukla ME, McCray PB, Perlman S, Ford B, Diekema DJ, Wellington M, Salinas JL, Pezzulo AA. Suspected COVID-19 Reinfections at a Tertiary Care Center, Iowa, 2020. Open Forum Infect Dis 2021; 8:ofab188. [PMID: 34322564 PMCID: PMC8083313 DOI: 10.1093/ofid/ofab188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/09/2021] [Indexed: 11/25/2022] Open
Affiliation(s)
- Takaaki Kobayashi
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Miguel E Ortiz
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Katherine L Imborek
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Mohammed Alsuhaibani
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Stephanie A Holley
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Alexandra Trannel
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Alexandre R Marra
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - William Etienne
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Kyle E Jenn
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Oluchi J Abosi
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Holly Meacham
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Lorinda L Sheeler
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Angelique Dains
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Mary E Kukla
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Paul B McCray
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Stanley Perlman
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Bradley Ford
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Daniel J Diekema
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Melanie Wellington
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Jorge L Salinas
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Alejandro A Pezzulo
- University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
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18
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Wakade RS, Huang M, Mitchell AP, Wellington M, Krysan DJ. Intravital Imaging of Candida albicans Identifies Differential In Vitro and In Vivo Filamentation Phenotypes for Transcription Factor Deletion Mutants. mSphere 2021; 6:e0043621. [PMID: 34160243 PMCID: PMC8265662 DOI: 10.1128/msphere.00436-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/07/2021] [Indexed: 01/12/2023] Open
Abstract
Candida albicans is an important cause of human fungal infections. A widely studied virulence trait of C. albicans is its ability to undergo filamentation to hyphae and pseudohyphae. Although yeast, pseudohyphae, and hyphae are present in pathological samples of infected mammalian tissue, it has been challenging to characterize the role of regulatory networks and specific genes during in vivo filamentation. In addition, the phenotypic heterogeneity of C. albicans clinical isolates is becoming increasingly recognized, while correlating this heterogeneity with pathogenesis remains an important goal. Here, we describe the use of an intravital imaging approach to characterize C. albicans filamentation in a mammalian model of infection by taking advantage of the translucence of mouse pinna (ears). Using this model, we have found that the in vitro and in vivo filamentation phenotypes of different C. albicans isolates can vary significantly, particularly when in vivo filamentation is compared to solid agar-based assays. We also show that the well-characterized transcriptional regulators Efg1 and Brg1 appear to play important roles both in vivo and in vitro. In contrast, Ume6 is much more important in vitro than in vivo. Finally, strains that are dependent on Bcr1 for in vitro filamentation are able to form filaments in vivo in its absence. This intravital imaging approach provides a new approach to the systematic characterization of this important virulence trait during mammalian infection. Our initial studies provide support for the notion that the regulation and initiation of C. albicans filamentation in vivo is distinct from in vitro induction. IMPORTANCE Candida albicans is one of the most common causes of fungal infections in humans. C. albicans undergoes a transition from a round yeast form to a filamentous form during infection, which is critical for its ability to cause disease. Although this transition has been studied in the laboratory for years, methods to do so in an animal model of infection have been limited. We have developed a microscopy method to visualize fluorescently labeled C. albicans undergoing this transition in the subcutaneous tissue of mice. Our studies indicate that the regulation of C. albicans filamentation during infection is distinct from that observed in laboratory conditions.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Manning Huang
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Kobayashi T, Trannel A, Holley SA, Alsuhaibani M, Abosi OJ, Jenn KE, Meacham H, Sheeler LL, Etienne W, Dains A, Casado F, Kukla ME, Ward E, Ford B, Edmond MB, Wellington M, Diekema DJ, Salinas JL. COVID-19 Serial Testing among Hospitalized Patients in a Midwest Tertiary Medical Center, July-September 2020. Clin Infect Dis 2020; 73:e3116-e3119. [PMID: 33103196 PMCID: PMC7665386 DOI: 10.1093/cid/ciaa1630] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Indexed: 01/12/2023] Open
Abstract
We implemented serial COVID-19 testing for inpatients with a negative test on admission. The conversion rate (negative to positive) on repeat testing was one percent. We identified patients during their incubation period and hospital-onset cases, rapidly isolated them, and potentially reduced exposures. Serial testing and infectiousness determination were resource intensive.
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Affiliation(s)
| | | | | | | | | | - Kyle E Jenn
- University of Iowa Hospitals & Clinics, Iowa City, Iowa
| | - Holly Meacham
- University of Iowa Hospitals & Clinics, Iowa City, Iowa
| | | | | | | | | | - Mary E Kukla
- University of Iowa Hospitals & Clinics, Iowa City, Iowa
| | - Emily Ward
- University of Iowa Hospitals & Clinics, Iowa City, Iowa
| | - Bradley Ford
- University of Iowa Hospitals & Clinics, Iowa City, Iowa
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20
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Wellington M, Htoo J, Van Kessel A, Columbus D. 362 Impact of dietary fiber and immune system stimulation on threonine requirement for whole body protein deposition in growing pigs. J Anim Sci 2018. [DOI: 10.1093/jas/sky404.392] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- M Wellington
- University of Saskatchewan/Prairie Swine Center Inc.,Saskatoon, SK, Canada
| | - J Htoo
- Evonik Nutrition & Care GmbH,No.4, Rodenbacher Chaussee, 63457, Hanau, Germany, Hanau-Wolfgang, Hessen, Germany
| | - A Van Kessel
- Department of Animal and Poultry Sci, University of Saskatchewan,Saskatoon, SK, Canada
| | - D Columbus
- Praire Swine Centre Inc./ University of Saskatchewan, Animal and Poultry Science,Saskatoon, SK, Canada
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21
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Affiliation(s)
- Melanie Wellington
- Department of Pediatrics, University of Rochester Medical Center, Rochester, New York 14642
| | | | - Kabir Elena Rustchenko
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642
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22
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Abstract
Invasive fungal infections remain a major cause of morbidity and mortality in immunocompromised patients, and such infections are a substantial burden to healthcare systems around the world. However, the clinically available armamentarium for invasive fungal diseases is limited to 3 main classes (i.e., polyenes, triazoles, and echinocandins), and each has defined limitations related to spectrum of activity, development of resistance, and toxicity. Further, current antifungal therapies are hampered by limited clinical efficacy, high rates of toxicity, and significant variability in pharmacokinetic properties. New antifungal agents, new formulations, and novel combination regimens may improve the care of patients in the future by providing improved strategies to combat challenges associated with currently available antifungal agents. Likewise, therapeutic drug monitoring may be helpful, but its present use remains controversial due to the lack of available data. This article discusses new facets of antifungal therapy with a focus on new antifungal formulations and the synergistic effects between drugs used in combination therapy.
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Affiliation(s)
- Ya-Lin Chang
- a Department of Plant Pathology and Microbiology , National Taiwan University , Taipei , Taiwan
| | - Shang-Jie Yu
- a Department of Plant Pathology and Microbiology , National Taiwan University , Taipei , Taiwan
| | - Joseph Heitman
- b Department of Molecular Genetics and Microbiology , Duke University , Durham , NC , USA
| | - Melanie Wellington
- c Department of Pediatrics , University of Rochester Medical Center , Rochester , NY , USA
| | - Ying-Lien Chen
- a Department of Plant Pathology and Microbiology , National Taiwan University , Taipei , Taiwan
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23
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Chidziva C, Matsekete J, Bandason T, Shamu S, Dzongodza T, Matinhira N, Mujuru HA, Kunzekwenyika C, Wellington M, Luthy R, Prescott C, Ferrand RA. Hearing impairment and deafness among HIV infected children and adolescents in Harare, Zimbabwe. Cent Afr J Med 2015; 61:56-61. [PMID: 29144062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
BACKGROUND Among HIV-infected children ear infections are recurrent and chronic, which may lead to hearing loss. OBJECTIVE To determine the prevalence, cause and severity of hearing impairment among HIV-infected children aged 5-17 years attending for HIV care in Harare. DESIGN AND SETTING An analytical cross-sectional survey conducted at Newlands Clinic, an opportunistic infections clinic in Harare. MATERIALS AND METHODS Participants underwent a standardised otoscopic examination of the ear and Pure Tone Audiometry (PTA). Factors associated with hearing impairment were investigated using multivariate logistic regression. RESULTS Three hundred and eighty (380) participants (55% female and mean age 11 years (SD: 3.3 years)) were consecutively recruited. The vast majority of participants (n=338; 89% were taking antiretroviral therapy (ART) for a median of 3 (IQR: 2-5) years at recruitment, and the most recent median CD4 Count (i.e. CD4 count measured within 6 months of the study recruitment) was 725 (IQR: 497-1000) cells/µL, with no difference by ART status. 61% (n= 231) of participants had an abnormal ear examination. Of the 359 participants who underwent audiometry, the prevalence of hearing impairment was 32.3% (95%CI: 27.5%-37.4%) based on a PTA threshold ≥26Db. Hearing impairment was associated with a recent CD4 count <350cell/µL (OR 2.1, P<0.037). CONCLUSION There is a high prevalence of hearing impairment among HIV-infected children and adolescents. Low CD4 count remains a risk factor even among those who are on ART. We recommend that HIV infected children and adolescents, particularly those with low CD4 counts, should have routine evaluation of hearing as part of HIV care.
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Harrison BD, Hashemi J, Bibi M, Pulver R, Bavli D, Nahmias Y, Wellington M, Sapiro G, Berman J. A tetraploid intermediate precedes aneuploid formation in yeasts exposed to fluconazole. PLoS Biol 2014; 12:e1001815. [PMID: 24642609 PMCID: PMC3958355 DOI: 10.1371/journal.pbio.1001815] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 02/06/2014] [Indexed: 11/19/2022] Open
Abstract
When exposed to the antifungal drug fluconazole, Candida albicans undergoes abnormal growth, forming three-lobed “trimeras.” These aneuploid trimeras turn out genetically variable progeny with varying numbers of chromosomes, increasing the odds of creating a drug-resistant strain. Candida albicans, the most prevalent human fungal pathogen, is generally diploid. However, 50% of isolates that are resistant to fluconazole (FLC), the most widely used antifungal, are aneuploid and some aneuploidies can confer FLC resistance. To ask if FLC exposure causes or only selects for aneuploidy, we analyzed diploid strains during exposure to FLC using flow cytometry and epifluorescence microscopy. FLC exposure caused a consistent deviation from normal cell cycle regulation: nuclear and spindle cycles initiated prior to bud emergence, leading to “trimeras,” three connected cells composed of a mother, daughter, and granddaughter bud. Initially binucleate, trimeras underwent coordinated nuclear division yielding four daughter nuclei, two of which underwent mitotic collapse to form a tetraploid cell with extra spindle components. In subsequent cell cycles, the abnormal number of spindles resulted in unequal DNA segregation and viable aneuploid progeny. The process of aneuploid formation in C. albicans is highly reminiscent of early stages in human tumorigenesis in that aneuploidy arises through a tetraploid intermediate and subsequent unequal DNA segregation driven by multiple spindles coupled with a subsequent selective advantage conferred by at least some aneuploidies during growth under stress. Finally, trimera formation was detected in response to other azole antifungals, in related Candida species, and in an in vivo model for Candida infection, suggesting that aneuploids arise due to azole treatment of several pathogenic yeasts and that this can occur during the infection process. Fungal infections are a particularly challenging problem in medicine due to the small number of effective antifungal drugs available. Fluconazole, the most commonly prescribed antifungal, prevents cells from growing but does not kill them, giving the fungal population a window of opportunity to become drug resistant. Candida albicans is the most prevalent fungal pathogen, and many fluconazole-resistant strains of this microbe have been isolated in the clinic. Fluconazole-resistant isolates often contain an abnormal number of chromosomes (a state called aneuploidy), and the additional copies of drug resistance genes on those chromosomes enable the cells to circumvent the drug. How Candida cells acquire abnormal chromosome numbers is a very important medical question—is aneuploidy merely passively selected for, or is it actively induced by the drug treatment? In this study, we found that fluconazole and other related azole antifungals induce abnormal cell cycle progression in which mother and daughter cells fail to separate after chromosome segregation. Following a further growth cycle, these cells form an unusual cell type that we have termed “trimeras”—three-lobed cells with two nuclei. The aberrant chromosome segregation dynamics in trimeras produce progeny with double the normal number of chromosomes. Unequal chromosome segregation in these progeny leads to an increase in the prevalence of aneuploidy in the population. We postulate that the increase in aneuploidy greatly increases the odds of developing drug resistance.
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Affiliation(s)
- Benjamin D. Harrison
- Department of Genetics, Cell, and Developmental Biology, University of Minnesota–Twin Cities, Minneapolis, Minnesota, United States of America
| | - Jordan Hashemi
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina, United States of America
| | - Maayan Bibi
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Rebecca Pulver
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Danny Bavli
- Alexander Grass Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yaakov Nahmias
- Alexander Grass Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Melanie Wellington
- Department of Pediatrics, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Guillermo Sapiro
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina, United States of America
| | - Judith Berman
- Department of Genetics, Cell, and Developmental Biology, University of Minnesota–Twin Cities, Minneapolis, Minnesota, United States of America
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
- * E-mail:
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Butts A, DiDone L, Koselny K, Baxter BK, Chabrier-Rosello Y, Wellington M, Krysan DJ. A repurposing approach identifies off-patent drugs with fungicidal cryptococcal activity, a common structural chemotype, and pharmacological properties relevant to the treatment of cryptococcosis. Eukaryot Cell 2013; 12:278-87. [PMID: 23243064 PMCID: PMC3571299 DOI: 10.1128/ec.00314-12] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 12/10/2012] [Indexed: 11/20/2022]
Abstract
New, more accessible therapies for cryptococcosis represent an unmet clinical need of global importance. We took a repurposing approach to identify previously developed drugs with fungicidal activity toward Cryptococcus neoformans, using a high-throughput screening assay designed to detect drugs that directly kill fungi. From a set of 1,120 off-patent medications and bioactive molecules, we identified 31 drugs/molecules with fungicidal activity, including 15 drugs for which direct antifungal activity had not previously been reported. A significant portion of the drugs are orally bioavailable and cross the blood-brain barrier, features key to the development of a widely applicable anticryptococcal agent. Structural analysis of this set revealed a common chemotype consisting of a hydrophobic moiety linked to a basic amine, features that are common to drugs that cross the blood-brain barrier and access the phagolysosome, two important niches of C. neoformans. Consistent with their fungicidal activity, the set contains eight drugs that are either additive or synergistic in combination with fluconazole. Importantly, we identified two drugs, amiodarone and thioridazine, with activity against intraphagocytic C. neoformans. Finally, the set of drugs is also enriched for molecules that inhibit calmodulin, and we have confirmed that seven drugs directly bind C. neoformans calmodulin, providing a molecular target that may contribute to the mechanism of antifungal activity. Taken together, these studies provide a foundation for the optimization of the antifungal properties of a set of pharmacologically attractive scaffolds for the development of novel anticryptococcal therapies.
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Affiliation(s)
| | | | | | | | | | | | - Damian J. Krysan
- Pediatrics
- Microbiology/Immunology, University of Rochester, Rochester, New York, USA
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Mitra S, Dolan K, Foster TH, Wellington M. Imaging morphogenesis of Candida albicans during infection in a live animal. J Biomed Opt 2010; 15:010504. [PMID: 20210419 PMCID: PMC2816988 DOI: 10.1117/1.3290243] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 11/20/2009] [Accepted: 11/24/2009] [Indexed: 05/28/2023]
Abstract
Candida albicans is an opportunistic human fungal pathogen that requires an intact host immune response to prevent disease. Thus, studying host-pathogen interactions is critical to understanding and preventing this disease. We report a new model infection system in which ongoing C. albicans infections can be imaged at high spatial resolution in the ears of living mice. Intradermal inoculation into mouse ears with a C. albicans strain expressing green fluorescent protein results in systemic C. albicans infection that can be imaged in vivo using confocal microscopy. We observed filamentous growth of the organism in vivo as well as formation of microabscesses. This model system will allow us to gain significant new information about C. albicans pathogenesis through studies of host-C. albicans interactions in the native environment.
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Dolan K, Montgomery S, Buchheit B, Didone L, Wellington M, Krysan DJ. Antifungal activity of tamoxifen: in vitro and in vivo activities and mechanistic characterization. Antimicrob Agents Chemother 2009; 53:3337-46. [PMID: 19487443 PMCID: PMC2715577 DOI: 10.1128/aac.01564-08] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 01/28/2009] [Accepted: 05/25/2009] [Indexed: 11/20/2022] Open
Abstract
Tamoxifen (TAM), an estrogen receptor antagonist used primarily to treat breast cancer, has well-recognized antifungal properties, but the activity of TAM has not been fully characterized using standardized (i.e., CLSI) in vitro susceptibility testing, nor has it been demonstrated in an in vivo model of fungal infection. In addition, its mechanism of action remains to be clearly defined at the molecular level. Here, we report that TAM displays in vitro activity (MIC, 8 to 64 microg/ml) against pathogenic yeasts (Candida albicans, other Candida spp., and Cryptococcus neoformans). In vivo, 200 mg/kg of body weight per day TAM reduced kidney fungal burden (-1.5 log(10) CFU per g tissue; P = 0.008) in a murine model of disseminated candidiasis. TAM is a known inhibitor of mammalian calmodulin, and TAM-treated yeast show phenotypes consistent with decreased calmodulin function, including lysis, decreased new bud formation, disrupted actin polarization, and decreased germ tube formation. The overexpression of calmodulin suppresses TAM toxicity, hypofunctional calmodulin mutants are hypersensitive to TAM, and TAM interferes with the interaction between Myo2p and calmodulin, suggesting that TAM targets calmodulin as part of its mechanism of action. Taken together, these experiments indicate that the further study of compounds related to TAM as antifungal agents is warranted.
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Affiliation(s)
- Kristy Dolan
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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Wellington M, Dolan K, Haidaris CG. Monocyte responses to Candida albicans are enhanced by antibody in cooperation with antibody-independent pathogen recognition. ACTA ACUST UNITED AC 2007; 51:70-83. [PMID: 17610517 DOI: 10.1111/j.1574-695x.2007.00278.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although most individuals are colonized with Candida albicans, only patients with insufficient or nonfunctional phagocytes develop life-threatening C. albicans disease. Because recognition of bacterial pathogens through phagocyte receptors for IgG (FcgammaR) is known to augment phagocyte responses, we postulated that antibody opsonization would enhance monocyte damage to C. albicans and subsequent tumor necrosis factor-alpha (TNF-alpha) production. After exposure to the human monocytic cell line THP-1, opsonized yeast showed an 89% decrease in metabolic activity, compared with 40% for unopsonized yeast (P<0.05). Culture supernatants contained 1316 pg mL(-1) of TNF-alpha after monocytes were exposed to opsonized yeast vs. 341 pg mL(-1) for unopsonized yeast (P=0.003). Similar results were obtained using peripheral blood mononuclear cells. Antibody opsonization of C. albicans germ tubes enhanced TNF-alpha production but did not affect organism damage. Antibody-dependent and antibody-independent factors were found to act synergistically to increase TNF-alpha production. ERK activation was important for both antibody-dependent and antibody-independent stimulation of TNF-alpha production, but not for monocyte-mediated organism damage. These data suggest that FcgammaR cooperates positively with antibody-independent recognition mechanisms in what may be a novel link between innate and adaptive immunity to C. albicans.
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Affiliation(s)
- Melanie Wellington
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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Abstract
We previously reported the occurrence of chromosome alterations in a Candida albicans prototrophic strain 3153A treated with 5-fluoro-orotic acid (5-FOA). In this study we investigated the mutagenic properties of 5-FOA with two derivatives of C. albicans strain CAF4-2 (ura3/ura3), each containing an ectopic copy of URA3 gene (ura3/ ura3 URA3) on a different chromosome. As expected, after the ura3/ura3 URA3 constructs were applied to 5-FOA containing solid medium, the "pop-outs" that lost URA3 appeared. However most of the "pop-outs" acquired various chromosome alterations. Thus constructs exposed to 5-FOA should be examined for chromosome alterations or the use of 5-FOA should be avoided.
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Affiliation(s)
- Melanie Wellington
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY 14642, USA
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Abstract
Treatment of a prototrophic laboratory strain of Candida albicans with 5-fluoro-orotic acid (5-FOA) produced two major types of mutants with chromosomal alterations, 5-FOA-resistant (FoaR) and those remaining sensitive (FoaS). Both major types remained Ura+. FoaR mutants, produced after a long exposure, contained either a duplication of chromosome 4b or an inner enlargement of chromosome 5b. The average mutant frequency was approximately 1.0 x 10(-5). The reverse mutation of FoaR to FoaS also caused the loss of either the extra chromosome 4b or the enlarged chromosome 5b, revealing a causal relationship between the resistance and the specific chromosome constitution. The cells remained sensitive after a relatively short 24 h exposure to 5-FOA medium, but the treatment induced non-specific changes in lengths of various chromosomes. Furthermore, FoaR type mutants acquired a notable chromosomal and phenotypic instability. Our results indicate the necessity of electrokaryotyping of strains that have been exposed to 5-FOA, especially with studies of gene function and with DNA microarray assays.
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Affiliation(s)
- Melanie Wellington
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY 14642, USA
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Wang YK, Das B, Huber DH, Wellington M, Kabir MA, Sherman F, Rustchenko E. Role of the 14–3–3 protein in carbon metabolism of the pathogenic yeastCandida albicans. Yeast 2004; 21:685-702. [PMID: 15197733 DOI: 10.1002/yea.1079] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We previously demonstrated that the pathogenic yeast Candida albicans effectively adapts to utilize L-sorbose (Sou+) by a novel mechanism based on the loss of one copy of chromosome 5, probably due to the reduction of copy number of a negative regulator located on this chromosome. We report here another negative regulator of L-sorbose utilization, an orthologue of the Saccharomyces cerevisiae BMH1 gene, which encodes the evolutionarily conserved protein 14-3-3. This essential gene is located on chromosome 1, does not have paralogues, and is supposedly a component of the regulatory network. Experiments involving disruption of one allele of BMH1 and overexpression of BMH1 revealed that BMH1 represses the transcription of SOU1, which is responsible for the utilization of L-sorbose. Although the exact mechanism of the interaction between BMH1 and SOU1 is not known, it is clear that the control is based on the ratio of gene copy number, and that BMH1 does not control the loss of chromosome 5, the major mechanism producing Sou+ mutants. We propose that function of BMH1 as a negative regulator of SOU1 contributes to a general cellular homeostasis. This is a first report on the role of the C. albicans essential gene BMH1 as a negative regulator of the utilization of secondary carbon source in yeast, which further substantiates the involvement of 14-3-3 proteins in diverse functions.
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Affiliation(s)
- Ying-Kai Wang
- Department of Biochemistry and Biophysics, University of Rochester Medical School, Rochester, NY 14642, USA
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Wellington M, Bliss JM, Haidaris CG. Enhanced phagocytosis of Candida species mediated by opsonization with a recombinant human antibody single-chain variable fragment. Infect Immun 2004; 71:7228-31. [PMID: 14638823 PMCID: PMC308946 DOI: 10.1128/iai.71.12.7228-7231.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Specific antibody opsonization significantly enhances the level of phagocytosis of Candida in the absence of complement. Furthermore, we have described a system using a recombinant human antibody single-chain variable fragment that allows a comparative study of phagocytosis of multiple Candida species opsonized via a common antigen.
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Affiliation(s)
- Melanie Wellington
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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Abstract
Candida is a leading cause of late onset infection (> 3 days of age) in the premature infant. Therefore, decisions about the diagnosis and management of infections caused by Candida are commonplace in the neonatal intensive care unit. Despite this fact, there are few comparative trials about treatment of neonatal Candida infections to guide the practitioner. New antifungals have been developed in the past decade and some clinical experience has been reported that can be used to guide the treatment of infants with serious Candida infections. This article reviews recent pertinent data with regard to dosing guidelines, efficacy, and toxicities of available systemic antifungal agents in the newborn.
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Affiliation(s)
- Joseph M Bliss
- Department of Pediatrics, Women and Infants' Hospital of Rhode Island, Brown University School of Medicine, Providence, RI 02905, USA
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Wellington M, Hall CB. Pacifier as a risk factor for acute otitis media. Pediatrics 2002; 109:351-2; author reply 353. [PMID: 11826228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
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35
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Affiliation(s)
- M Wellington
- University of Rochester School of Medicine and Dentistry, NY, USA
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Wellington M. Stanford Health Partners: rationale and early experiences in establishing physician group visits and chronic disease self-management workshops. J Ambul Care Manage 2001; 24:10-6. [PMID: 11433551 DOI: 10.1097/00004479-200107000-00004] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chronic disease is a major public health problem. The day-to-day management of a chronic illness requires accurate patient reporting and timely medical response. Patient group visits with the primary care physician and lay-led patient education workshops improve the provider-physician relationship, promote patient self-efficacy and self-management of chronic diseases, and facilitate positive health care outcomes. This article describes how group visits are being integrated into the clinical routine of a health care system.
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Affiliation(s)
- M Wellington
- Stanford Health Partners, Stanford University Medical Center, Palo Alto, California, USA
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Nathoo KJ, Porteous JE, Siziya S, Wellington M, Mason E. Predictors of mortality in children hospitalized with dysentery in Harare, Zimbabwe. Cent Afr J Med 1998; 44:272-6. [PMID: 10910572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
OBJECTIVES To document the pattern of complications and identify risk factors for subsequent mortality in a hospitalized paediatric population during a Shigella dysenteriae type 1 epidemic. DESIGN Hospital based prognostic study. SETTING Paediatric wards in Harare and Parirenyatwa tertiary referral hospitals. SUBJECTS All children aged one month to 12 years admitted to the wards with a history of bloody diarrhoea between January 1993 to June 30 1994 were included in the study (n = 312). MAIN OUTCOME MEASURES Patterns of complications and predictors of mortality. RESULTS The peak age group of the patients was 12 to 23 months. Ninety five children died giving an overall case fatality rate (CFR) of 30.4% (95% CI, 25.3 to 35.6). One third (n = 107) had haemolytic uraemic syndrome (HUS), among whom the CFR was 43%. Other complications included altered consciousness (35%), seizures (12%), coma (4.5%), severe dehydration (14%), abdominal distention (17%), rectal prolapse (5%) and ileus (6%). In a multivariate analysis, temperature < 36 degrees C (OR 2.12; 95% CI, 1.33 to 3.39), severe dehydration (OR, 1.70; 95% CI, 1.15 to 2.53), hyperkalemia (> 5.5 mmol/L) (OR, 1.74; 95% CI, 1.01 to 1.97), hyponatremia (< 120 mmol/L) (OR, 1.57; 95% CI, 1.17 to 2.11), urea (> 8 mmol/L) (OR, 1.74; 95% CI, 1.29 to 2.36), and abdominal distention (OR, 1.67; 95% CI, 1.16 to 2.41) were found to be predictors of mortality. CONCLUSION Some of the major clinical and laboratory features allowing the early identification of children at increased risk of dying during dysentery outbreaks have been delineated. The high fatality associated with complicated dysentery highlights the need for preventive strategies which are sustainable in the region.
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Affiliation(s)
- K J Nathoo
- Department of Community Medicine, University of Zimbabwe Medical School, Harare, Zimbabwe
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Abstract
OBJECTIVE To obtain information on risk factors and health-seeking behavior of men with sexually transmitted diseases (STDs) attending primary care clinics. STUDY DESIGN Unmatched case-control. METHODS Cases consisted of 256 consecutive men with genital ulcer disease (GUD) and 256 with other STDs. Control subjects (N = 256) were recruited from every third man with non-STD-related complaints. All subjects were at least 15 years of age. A structured questionnaire was administered. RESULTS Genital ulcer disease cases reported more frequent sexual intercourse with a commercial sex worker (odds ratio [OR] = 17.4; 95% confidence intervals [CI] = 7.8-40.0) and a recent new sexual contact (OR = 6.7; CI = 3.3-14.1). Similarly, STD cases reported more frequent sexual contact with a commercial sex worker (OR = 3.4; CI = 2.0-5.6) and a recent new sexual contact (OR = 7.9; CI = 3.9-16.3). Reported condom use was less than 30% with all partner types. Of all STD cases, 80% sought treatment at the primary care clinics, with 35% delaying more than 7 days before seeking treatment. CONCLUSIONS Culturally appropriate behavioral educational programs are advocated to reduce the risk of transmission and the period for seeking treatment for all STDs.
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Wellington M. We must continue to work hard for unity regarding educational preparation. ANNA J 1997; 24:129. [PMID: 9180423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Mason PR, Nathoo KJ, Wellington M, Mason E. Antimicrobial susceptibilities of Shigella dysenteriae type 1 isolated in Zimbabwe--implications for the management of dysentery. Cent Afr J Med 1995; 41:132-7. [PMID: 7788685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Shigella dysenteriae type 1 was cultured from 56/170 (33 pc) rectal swab specimens collected from patients presenting to hospitals in Harare, Zimbabwe with dysentery. All of the isolates were resistant in vitro to trimethoprim-sulfamethoxazole, with MICs > 32 mg/l, and all except one were resistant to ampicillin, most with an MIC > 256 mg/l. One isolate was resistant to nalidixic acid (MIC > 256 mg/l), but all of the others were sensitive, most with an MIC of 2 mg/l or less. Using antibiotic disks, 96 pc isolates were resistant to chloromphenicol and 94 pc to tetracycline. All isolates were sensitive in vitro to gentamicin. On the basis of these findings, we suggest that commonly available antibiotics including ampicillin, cotrimoxazole, chloramphenicol or tetracycline should not be used for the treatment of dysentery. The most appropriate antimicrobial agent at the present time would be nalidixic acid. Resistance to this is, however, likely to emerge and data on susceptibilities to fluoroquinolones as well as to cephalosporins should be obtained so that further recommendations can be given timeously.
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Affiliation(s)
- P R Mason
- University of Zimbabwe Medical School, Department of Medical Microbiology, Avondale, Harare
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41
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Wellington M, Mahomed K, Ndoro E. Reference values for glucose tolerance test in the urban Zimbabwean pregnant woman. Cent Afr J Med 1992; 38:182-4. [PMID: 1423546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A 50 g oral glucose tolerance test (OGTT) was performed on normal pregnant urban Zimbabwean women at 26-28 weeks (n = 65) and 36-40 weeks (n = 72) gestation. Women with factors predisposing to impaired glucose tolerance were excluded. The fasting, one hour and two hours values were compared to the North American standards as proposed by O'Sullivan and Mahan which are currently in use. The mean fasting levels were significantly higher and those at one and two hours significantly lower than the standards. The study also failed to demonstrate impairment of glucose tolerance with advancing gestation. These may have implications in the screening for impaired glucose tolerance in our African population.
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Affiliation(s)
- M Wellington
- City Health Department, Avondale, Harare, Zimbabwe
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Wellington M. Decentralization: how it affects nurses. Nurs Outlook 1986; 34:36-9. [PMID: 3632835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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