Browsing by Author "Chiller, Tom"

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    Factors associated with mortality in transplant patients with invasive aspergillosis.
    (Clin Infect Dis, 2010-06-15) Baddley, John W; Andes, David R; Marr, Kieren A; Kontoyiannis, Dimitrios P; Alexander, Barbara D; Kauffman, Carol A; Oster, Robert A; Anaissie, Elias J; Walsh, Thomas J; Schuster, Mindy G; Wingard, John R; Patterson, Thomas F; Ito, James I; Williams, O Dale; Chiller, Tom; Pappas, Peter G
    BACKGROUND: Invasive aspergillosis (IA) is an important cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients. The purpose of this study was to evaluate factors associated with mortality in transplant patients with IA. METHODS: Transplant patients from 23 US centers were enrolled from March 2001 to October 2005 as part of the Transplant Associated Infection Surveillance Network. IA cases were identified prospectively in this cohort through March 2006, and data were collected. Factors associated with 12-week all-cause mortality were determined by logistic regression analysis and Cox proportional hazards regression. RESULTS: Six-hundred forty-two cases of proven or probable IA were evaluated, of which 317 (49.4%) died by the study endpoint. All-cause mortality was greater in HSCT patients (239 [57.5%] of 415) than in SOT patients (78 [34.4%] of 227; P<.001). Independent poor prognostic factors in HSCT patients were neutropenia, renal insufficiency, hepatic insufficiency, early-onset IA, proven IA, and methylprednisolone use. In contrast, white race was associated with decreased risk of death. Among SOT patients, hepatic insufficiency, malnutrition, and central nervous system disease were poor prognostic indicators, whereas prednisone use was associated with decreased risk of death. Among HSCT or SOT patients who received antifungal therapy, use of an amphotericin B preparation as part of initial therapy was associated with increased risk of death. CONCLUSIONS: There are multiple variables associated with survival in transplant patients with IA. Understanding these prognostic factors may assist in the development of treatment algorithms and clinical trials.
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    Leave no one behind: response to new evidence and guidelines for the management of cryptococcal meningitis in low-income and middle-income countries.
    (The Lancet. Infectious Diseases, 2019-04) Loyse, Angela; Burry, Jessica; Cohn, Jennifer; Ford, Nathan; Chiller, Tom; Ribeiro, Isabela; Koulla-Shiro, Sinata; Mghamba, Janneth; Ramadhani, Angela; Nyirenda, Rose; Aliyu, Sani H; Wilson, Douglas; Le, Thuy; Oladele, Rita; Lesikari, Sokoine; Muzoora, Conrad; Kalata, Newton; Temfack, Elvis; Mapoure, Yacouba; Sini, Victor; Chanda, Duncan; Shimwela, Meshack; Lakhi, Shabir; Ngoma, Jonathon; Gondwe-Chunda, Lilian; Perfect, Chase; Shroufi, Amir; Andrieux-Meyer, Isabelle; Chan, Adrienne; Schutz, Charlotte; Hosseinipour, Mina; Van der Horst, Charles; Klausner, Jeffrey D; Boulware, David R; Heyderman, Robert; Lalloo, David; Day, Jeremy; Jarvis, Joseph N; Rodrigues, Marcio; Jaffar, Shabbar; Denning, David; Migone, Chantal; Doherty, Megan; Lortholary, Olivier; Dromer, Françoise; Stack, Muirgen; Molloy, Síle F; Bicanic, Tihana; van Oosterhout, Joep; Mwaba, Peter; Kanyama, Cecilia; Kouanfack, Charles; Mfinanga, Sayoki; Govender, Nelesh; Harrison, Thomas S
    In 2018, WHO issued guidelines for the diagnosis, prevention, and management of HIV-related cryptococcal disease. Two strategies are recommended to reduce the high mortality associated with HIV-related cryptococcal meningitis in low-income and middle-income countries (LMICs): optimised combination therapies for confirmed meningitis cases and cryptococcal antigen screening programmes for ambulatory people living with HIV who access care. WHO's preferred therapy for the treatment of HIV-related cryptococcal meningitis in LMICs is 1 week of amphotericin B plus flucytosine, and the alternative therapy is 2 weeks of fluconazole plus flucytosine. In the ACTA trial, 1-week (short course) amphotericin B plus flucytosine resulted in a 10-week mortality of 24% (95% CI -16 to 32) and 2 weeks of fluconazole and flucytosine resulted in a 10-week mortality of 35% (95% CI -29 to 41). However, with widely used fluconazole monotherapy, mortality because of HIV-related cryptococcal meningitis is approximately 70% in many African LMIC settings. Therefore, the potential to transform the management of HIV-related cryptococcal meningitis in resource-limited settings is substantial. Sustainable access to essential medicines, including flucytosine and amphotericin B, in LMICs is paramount and the focus of this Personal View.
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    Live Imaging of Host-Parasite Interactions in a Zebrafish Infection Model Reveals Cryptococcal Determinants of Virulence and Central Nervous System Invasion.
    (MBio, 2015-09-29) Tenor, Jennifer L; Oehlers, Stefan H; Yang, Jialu L; Tobin, David M; Perfect, John R
    UNLABELLED: The human fungal pathogen Cryptococcus neoformans is capable of infecting a broad range of hosts, from invertebrates like amoebas and nematodes to standard vertebrate models such as mice and rabbits. Here we have taken advantage of a zebrafish model to investigate host-pathogen interactions of Cryptococcus with the zebrafish innate immune system, which shares a highly conserved framework with that of mammals. Through live-imaging observations and genetic knockdown, we establish that macrophages are the primary immune cells responsible for responding to and containing acute cryptococcal infections. By interrogating survival and cryptococcal burden following infection with a panel of Cryptococcus mutants, we find that virulence factors initially identified as important in causing disease in mice are also necessary for pathogenesis in zebrafish larvae. Live imaging of the cranial blood vessels of infected larvae reveals that C. neoformans is able to penetrate the zebrafish brain following intravenous infection. By studying a C. neoformans FNX1 gene mutant, we find that blood-brain barrier invasion is dependent on a known cryptococcal invasion-promoting pathway previously identified in a murine model of central nervous system invasion. The zebrafish-C. neoformans platform provides a visually and genetically accessible vertebrate model system for cryptococcal pathogenesis with many of the advantages of small invertebrates. This model is well suited for higher-throughput screening of mutants, mechanistic dissection of cryptococcal pathogenesis in live animals, and use in the evaluation of therapeutic agents. IMPORTANCE: Cryptococcus neoformans is an important opportunistic pathogen that is estimated to be responsible for more than 600,000 deaths worldwide annually. Existing mammalian models of cryptococcal pathogenesis are costly, and the analysis of important pathogenic processes such as meningitis is laborious and remains a challenge to visualize. Conversely, although invertebrate models of cryptococcal infection allow high-throughput assays, they fail to replicate the anatomical complexity found in vertebrates and, specifically, cryptococcal stages of disease. Here we have utilized larval zebrafish as a platform that overcomes many of these limitations. We demonstrate that the pathogenesis of C. neoformans infection in zebrafish involves factors identical to those in mammalian and invertebrate infections. We then utilize the live-imaging capacity of zebrafish larvae to follow the progression of cryptococcal infection in real time and establish a relevant model of the critical central nervous system infection phase of disease in a nonmammalian model.
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    Looking for fungi in all the right places: screening for cryptococcal disease and other AIDS-related mycoses among patients with advanced HIV disease.
    (Curr Opin HIV AIDS, 2017-03) Greene, Greg; Sriruttan, Charlotte; Le, Thuy; Chiller, Tom; Govender, Nelesh P
    PURPOSE OF REVIEW: As HIV treatment programmes scale up to meet the UNAIDS 90-90-90 goals, care must be taken to start antiretroviral treatment safely in patients with advanced disease (CD4 counts <200 cells/μl) who are simultaneously at risk for opportunistic infections and immune reconstitution inflammatory syndrome. Invasive fungal diseases pose a great threat at this critical time point, though the development of inexpensive and highly accurate rapid diagnostic tests has changed the approach HIV programmes are taking to reduce the high mortality associated with these opportunistic infections. This article summarizes recent advances and findings in fungal opportunistic infection diagnostics with a focus on screening to prevent cryptococcal meningitis. RECENT FINDINGS: Cryptococcal antigen (CrAg) screening using a lateral flow assay platform is cost-effective and feasible to implement as either a laboratory reflex or point-of-care test. Recent CrAg screening pilots have elucidated the varying prevalence of cryptococcal antigenemia across geographic regions, which may aid programme planning. Evidence from recently completed clinical trials provides a strong motivation for the use of CrAg titer to refine treatment options for patients with subclinical cryptococcal disease. SUMMARY: Although several operational barriers to programme effectiveness still need to be addressed, the utility of CrAg screening using inexpensive and accurate antigen assays has been demonstrated in real-world HIV programmes, paving the way for development and testing of other fungal opportunistic infection screening strategies and for an integrated advanced HIV disease testing package to reduce AIDS mortality and ensure safe antiretroviral treatment initiation.
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    Novel antifungals and treatment approaches to tackle resistance and improve outcomes of invasive fungal disease
    (Clinical Microbiology Reviews) Hoenigl, Martin; Arastehfar, Amir; Arendrup, Maiken Cavling; Brüggemann, Roger; Carvalho, Agostinho; Chiller, Tom; Chen, Sharon; Egger, Matthias; Feys, Simon; Gangneux, Jean-Pierre; Gold, Jeremy AW; Groll, Andreas H; Heylen, Jannes; Jenks, Jeffrey D; Krause, Robert; Lagrou, Katrien; Lamoth, Frédéric; Prattes, Juergen; Sedik, Sarah; Wauters, Joost; Wiederhold, Nathan P; Thompson, George R
    SUMMARY Fungal infections are on the rise, driven by a growing population at risk and climate change. Currently available antifungals include only five classes, and their utility and efficacy in antifungal treatment are limited by one or more of innate or acquired resistance in some fungi, poor penetration into “sequestered” sites, and agent-specific side effect which require frequent patient reassessment and monitoring. Agents with novel mechanisms, favorable pharmacokinetic (PK) profiles including good oral bioavailability, and fungicidal mechanism(s) are urgently needed. Here, we provide a comprehensive review of novel antifungal agents, with both improved known mechanisms of actions and new antifungal classes, currently in clinical development for treating invasive yeast, mold (filamentous fungi), Pneumocystis jirovecii infections, and dimorphic fungi (endemic mycoses). We further focus on inhaled antifungals and the role of immunotherapy in tackling fungal infections, and the specific PK/pharmacodynamic profiles, tissue distributions as well as drug-drug interactions of novel antifungals. Finally, we review antifungal resistance mechanisms, the role of use of antifungal pesticides in agriculture as drivers of drug resistance, and detail detection methods for antifungal resistance.