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"Chiller, Tom"
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Global burden of disease of HIV-associated cryptococcal meningitis: an updated analysis
by
Rajasingham, Radha
,
Govender, Nelesh P
,
Park, Benjamin J
in
Acquired immune deficiency syndrome
,
Adolescent
,
Adult
2017
Cryptococcus is the most common cause of meningitis in adults living with HIV in sub-Saharan Africa. Global burden estimates are crucial to guide prevention strategies and to determine treatment needs, and we aimed to provide an updated estimate of global incidence of HIV-associated cryptococcal disease.
We used 2014 Joint UN Programme on HIV and AIDS estimates of adults (aged >15 years) with HIV and antiretroviral therapy (ART) coverage. Estimates of CD4 less than 100 cells per μL, virological failure incidence, and loss to follow-up were from published multinational cohorts in low-income and middle-income countries. We calculated those at risk for cryptococcal infection, specifically those with CD4 less than 100 cells/μL not on ART, and those with CD4 less than 100 cells per μL on ART but lost to follow-up or with virological failure. Cryptococcal antigenaemia prevalence by country was derived from 46 studies globally. Based on cryptococcal antigenaemia prevalence in each country and region, we estimated the annual numbers of people who are developing and dying from cryptococcal meningitis.
We estimated an average global cryptococcal antigenaemia prevalence of 6·0% (95% CI 5·8–6·2) among people with a CD4 cell count of less than 100 cells per μL, with 278 000 (95% CI 195 500–340 600) people positive for cryptococcal antigen globally and 223 100 (95% CI 150 600–282 400) incident cases of cryptococcal meningitis globally in 2014. Sub-Saharan Africa accounted for 73% of the estimated cryptococcal meningitis cases in 2014 (162 500 cases [95% CI 113 600–193 900]). Annual global deaths from cryptococcal meningitis were estimated at 181 100 (95% CI 119 400–234 300), with 135 900 (75%; [95% CI 93 900–163 900]) deaths in sub-Saharan Africa. Globally, cryptococcal meningitis was responsible for 15% of AIDS-related deaths (95% CI 10–19).
Our analysis highlights the substantial ongoing burden of HIV-associated cryptococcal disease, primarily in sub-Saharan Africa. Cryptococcal meningitis is a metric of HIV treatment programme failure; timely HIV testing and rapid linkage to care remain an urgent priority.
None.
Journal Article
Declining Incidence of Candidemia and the Shifting Epidemiology of Candida Resistance in Two US Metropolitan Areas, 2008–2013: Results from Population-Based Surveillance
2015
Recent reports have demonstrated a decline in bacterial bloodstream infections (BSIs) following adherence to central line insertion practices; however, declines have been less evident for BSIs due to Candida species.
We conducted active, population-based laboratory surveillance for candidemia in metropolitan Atlanta, GA and Baltimore, MD over a 5-year period. We calculated annual candidemia incidence and antifungal drug resistance rates.
We identified 3,848 candidemia cases from 2008-2013. Compared with 2008, candidemia incidence per 100,000 person-years decreased significantly by 2013 in both locations (GA: 14.1 to 9.5, p<0.001; MD: 30.9 to 14.4, p<0.001). A total of 3,255 cases (85%) had a central venous catheter (CVC) in place within 2 days before the BSI culture date. In both locations, the number of CVC-associated cases declined (GA: 473 to 294; MD: 384 to 151). Candida albicans (CA, 36%) and Candida glabrata (CG, 27%) were the most common species recovered. In both locations, the proportion of cases with fluconazole resistance decreased (GA: 8.0% to 7.1%, -10%; MD: 6.6% to 4.9%, -25%), while the proportion of cases with an isolate resistant to an echinocandin increased (GA: 1.2% to 2.9%, +147%; MD: 2.0% to 3.5%, +77%). Most (74%) echinocandin-resistant isolates were CG; 17 (<1%) isolates were resistant to both drug categories (multidrug resistant [MDR], 16/17 were CG). The proportion of CG cases with MDR Candida increased from 1.8% to 2.6%.
We observed a significant decline in the incidence of candidemia over a five-year period, and increases in echinocandin-resistant and MDR Candida. Efforts to strengthen infection control practices may be preventing candidemia among high-risk patients. Further surveillance for resistant Candida is warranted.
Journal Article
The global burden of HIV-associated cryptococcal infection in adults in 2020: a modelling analysis
by
Rajasingham, Radha
,
Meya, David B
,
Govender, Nelesh P
in
Acquired immune deficiency syndrome
,
Acquired Immunodeficiency Syndrome - complications
,
Adult
2022
Cryptococcal meningitis is the most common cause of meningitis in adults living with HIV in sub-Saharan Africa. The estimates of national, regional, and global burden of cryptococcal meningitis are essential to guide prevention strategies and determine needs for diagnostic tests and treatments. We present a 2020 estimate of the global burden of HIV-associated cryptococcal infection (antigenaemia), cryptococcal meningitis, and cryptococcal-associated deaths.
We defined advanced HIV disease as adults with a CD4 count of less than 200 cells/μL, as this group is at highest risk for cryptococcosis. We used UNAIDS estimates (2019–20) and population-based HIV impact assessment surveys (2016–18) to estimate the number of adults with CD4 counts of less than 200 cells/μL at risk for cryptococcosis, by country and region. Secondly, we summarised cryptococcal antigenaemia prevalence in those with a CD4 count of less than 200 cells/μL by reviewing published literature. Thereafter, we calculated the number of cryptococcal antigen (CrAg)-positive people in each country and region by multiplying the number with advanced HIV disease at risk for cryptococcal infection by the cryptococcal antigenaemia prevalence of the respective country or region. We estimated progression from cryptococcal antigenaemia to meningitis or death based on estimates from the published literature.
We estimated that there were 4·3 million (IQR 3·0–4·8) adults with HIV and CD4 counts of less than 200 cells/μL globally in 2020. We calculated a mean global cryptococcal antigenaemia prevalence of 4·4% (95% CI 1·6–7·4) among HIV-positive people with CD4 counts of less than 200 cells/μL, corresponding to 179 000 cases (IQR 133 000–219 000) of cryptococcal antigenaemia globally in 2020. Annually, we estimated that there are 152 000 cases (111 000–185 000) of cryptococcal meningitis, resulting in 112 000 cryptococcal-related deaths (79 000–134 000). Globally, cryptococcal disease accounts for 19% (13–24) of AIDS-related mortality.
Despite a reduction in the estimated absolute global burden of HIV-associated cryptococcal meningitis compared with 2014, likely to be due to antiretroviral therapy expansion, cryptococcal disease still accounts for 19% of AIDS-related deaths, similar to 2014 estimates. To end cryptococcal meningitis deaths by 2030, cryptococcal diagnostics, meningitis treatments, and implementation of preventive screening are urgently needed.
None.
Journal Article
Estimation of Direct Healthcare Costs of Fungal Diseases in the United States
by
Chiller, Tom
,
Jackson, Brendan R.
,
Beer, Karlyn D.
in
ARTICLES AND COMMENTARIES
,
Cost of Illness
,
Health Care Costs - statistics & numerical data
2019
Abstract
Background
Fungal diseases range from relatively-minor superficial and mucosal infections to severe, life-threatening systemic infections. Delayed diagnosis and treatment can lead to poor patient outcomes and high medical costs. The overall burden of fungal diseases in the United States is challenging to quantify, because they are likely substantially underdiagnosed.
Methods
To estimate the total, national, direct medical costs associated with fungal diseases from a healthcare payer perspective, we used insurance claims data from the Truven Health MarketScan 2014 Research Databases, combined with hospital discharge data from the 2014 Healthcare Cost and Utilization Project National Inpatient Sample and outpatient visit data from the 2005–2014 National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey. All costs were adjusted to 2017 dollars.
Results
We estimate that fungal diseases cost more than $7.2 billion in 2017, including $4.5 billion from 75055 hospitalizations and $2.6 billion from 8993230 outpatient visits. Hospitalizations for Candida infections (n = 26735, total cost $1.4 billion) and Aspergillus infections (n = 14820, total cost $1.2 billion) accounted for the highest total hospitalization costs of any disease. Over half of outpatient visits were for dermatophyte infections (4981444 visits, total cost $802 million), and 3639037 visits occurred for non-invasive candidiasis (total cost $1.6 billion).
Conclusions
Fungal diseases impose a considerable economic burden on the healthcare system. Our results likely underestimate their true costs, because they are underdiagnosed. More comprehensive estimates of the public health impact of these diseases are needed to improve their recognition, prevention, diagnosis, and treatment.
To provide insight into the burden of fungal diseases in the United States, we used several administrative data sources to estimate their total direct healthcare costs. We estimate that fungal disease healthcare costs exceed $7 billion annually.
Journal Article
Re-drawing the Maps for Endemic Mycoses
by
Chiller, Tom
,
Adenis, Antoine A.
,
Poplin, Victoria
in
Biomedical and Life Sciences
,
Blastomycosis
,
Blastomycosis - epidemiology
2020
Endemic mycoses such as histoplasmosis, coccidioidomycosis, blastomycosis, paracoccidioidomycosis, and talaromycosis are well-known causes of focal and systemic disease within specific geographic areas of known endemicity. However, over the past few decades, there have been increasingly frequent reports of infections due to endemic fungi in areas previously thought to be “non-endemic.” There are numerous potential reasons for this shift such as increased use of immune suppressive medications, improved diagnostic tests, increased disease recognition, and global factors such as migration, increased travel, and climate change. Regardless of the causes, it has become evident that our previous understanding of endemic regions for these fungal diseases needs to evolve. The epidemiology of the newly described
Emergomyces
is incomplete; our understanding of it continues to evolve. This review will focus on the evidence underlying the established areas of endemicity for these mycoses as well as new data and reports from medical literature that support the re-thinking these geographic boundaries. Updating the endemic fungi maps would inform clinical practice and global surveillance of these diseases.
Journal Article
Trends in Agricultural Triazole Fungicide Use in the United States, 1992–2016 and Possible Implications for Antifungal-Resistant Fungi in Human Disease
by
Chiller, Tom M.
,
Jackson, Brendan R.
,
Toda, Mitsuru
in
Agriculture
,
Agrochemicals
,
Antifungal agents
2021
The fungus
(
) is the leading cause of invasive mold infections, which cause severe disease and death in immunocompromised people. Use of triazole antifungal medications in recent decades has improved patient survival; however, triazole-resistant infections have become common in parts of Europe and are emerging in the United States. Triazoles are also a class of fungicides used in plant agriculture, and certain triazole-resistant
strains found causing disease in humans have been linked to environmental fungicide use.
We examined U.S. temporal and geographic trends in the use of triazole fungicides using U.S. Geological Survey agricultural pesticide use estimates.
Based on our analysis, overall tonnage of triazole fungicide use nationwide was relatively constant during 1992-2005 but increased
during 2006-2016 to
in 2016. During 1992-2005, triazole fungicide use occurred mostly in orchards and grapes, wheat, and other crops, but recent increases in use have occurred primarily in wheat, corn, soybeans, and other crops, particularly in Midwest and Southeast states. We conclude that, given the chemical similarities between triazole fungicides and triazole antifungal drugs used in human medicine, increased monitoring for environmental and clinical triazole resistance in
would improve overall understanding of these interactions, as well as help identify strategies to mitigate development and spread of resistance. https://doi.org/10.1289/EHP7484.
Journal Article
Approach to the Investigation and Management of Patients With Candida auris, an Emerging Multidrug-Resistant Yeast
by
Kallen, Alexander
,
Chiller, Tom M
,
Vallabhaneni, Snigdha
in
Antifungal Agents - therapeutic use
,
Candida
,
Candida - drug effects
2018
Candida auris is an emerging, multidrug-resistant yeast that can spread in healthcare settings. It can cause invasive infections with high mortality and is difficult to identify using traditional yeast identification methods. Candida auris has been reported in more than a dozen countries, and as of August 2017, 112 clinical cases have been reported in the United States. Candida auris can colonize skin and persist in the healthcare environment, allowing for transmission between patients. Prompt investigation and aggressive interventions, including notification to public health agencies, implementation of contact precautions, thorough environmental cleaning and disinfection, infection control assessments, contact tracing and screening of contacts to assess for colonization, and retrospective review of microbiology records and prospective surveillance for cases at laboratories are all needed to limit the spread of C. auris. This review summarizes the current recommended approach to manage cases and control transmission of C. auris in healthcare facilities.
Journal Article
Evaluation of a national cryptococcal antigen screening program for HIV-infected patients in Uganda: A cost-effectiveness modeling analysis
by
Rajasingham, Radha
,
Chiller, Tom M.
,
Nakawuka, Mina
in
Acquired immune deficiency syndrome
,
Adult
,
AIDS
2019
Cryptococcal meningitis accounts for 15% of AIDS-related mortality. Cryptococcal antigen (CrAg) is detected in blood weeks before onset of meningitis, and CrAg positivity is an independent predictor of meningitis and death. CrAg screening for patients with advanced HIV and preemptive treatment is recommended by the World Health Organization, though implementation remains limited. Our objective was to evaluate costs and mortality reduction (lives saved) from a national CrAg screening program across Uganda.
We created a decision analytic model to evaluate CrAg screening. CrAg screening was considered for those with a CD4<100 cells/μL per national and international guidelines, and in the context of a national HIV test-and-treat program where CD4 testing was not available. Costs (2016 USD) were estimated for screening, preemptive therapy, hospitalization, and maintenance therapy. Parameter assumptions were based on large prospective CrAg screening studies in Uganda, and clinical trials from sub Saharan Africa. CrAg positive (CrAg+) persons could be: (a) asymptomatic and thus eligible for preemptive treatment with fluconazole; or (b) symptomatic with meningitis with hospitalization.
In the base case model for 1 million persons with a CD4 test annually, 128,000 with a CD4<100 cells/μL were screened, and 8,233 were asymptomatic CrAg+ and received preemptive therapy. Compared to no screening and treatment, CrAg screening and treatment in the base case cost $3,356,724 compared to doing nothing, and saved 7,320 lives, for a cost of $459 per life saved, with the $3.3 million in cost savings derived from fewer patients developing fulminant meningitis. In the scenario of a national HIV test-and-treat program, of 1 million HIV-infected persons, 800,000 persons were screened, of whom 640,000 returned to clinic, and 8,233 were incident CrAg positive (CrAg prevalence 1.4%). The total cost of a CrAg screening and treatment program was $4.16 million dollars, with 2,180 known deaths. Conversely, without CrAg screening, the cost of treating meningitis was $3.09 million dollars with 3,806 deaths. Thus, despite the very low CrAg prevalence of 1.4% in the general HIV-infected population, and inadequate retention-in-care, CrAg screening averted 43% of deaths from cryptococcal meningitis at a cost of $662 per death averted.
CrAg screening and treatment programs are cost-saving and lifesaving, assuming preemptive treatment is 77% effective in preventing death, and could be adopted and implemented by ministries of health to reduce mortality in those with advanced HIV disease. Even within HIV test-and-treat programs where CD4 testing is not performed, and CrAg prevalence is only 1.4%, CrAg screening is cost-effective.
Journal Article
The importance of antimicrobial resistance in medical mycology
2022
Prior to the SARS-CoV-2 pandemic, antibiotic resistance was listed as the major global health care priority. Some analyses, including the O’Neill report, have predicted that deaths due to drug-resistant bacterial infections may eclipse the total number of cancer deaths by 2050. Although fungal infections remain in the shadow of public awareness, total attributable annual deaths are similar to, or exceeds, global mortalities due to malaria, tuberculosis or HIV. The impact of fungal infections has been exacerbated by the steady rise of antifungal drug resistant strains and species which reflects the widespread use of antifungals for prophylaxis and therapy, and in the case of azole resistance in
Aspergillus
, has been linked to the widespread agricultural use of antifungals. This review, based on a workshop hosted by the Medical Research Council and the University of Exeter, illuminates the problem of antifungal resistance and suggests how this growing threat might be mitigated.
The impact of fungal infections on human health has been exacerbated by the rise of antifungal drug resistance. In this Review, the authors outline the problem of antifungal resistance and suggest how this growing threat might be mitigated.
Journal Article
World Health Organization Ranking of Antimicrobials According to Their Importance in Human Medicine: A Critical Step for Developing Risk Management Strategies for the Use of Antimicrobials in Food Production Animals
by
Chiller, Tom M.
,
Aarestrup, Frank M.
,
Powers, John H.
in
Animals
,
Anti-Bacterial Agents - therapeutic use
,
Antibiotic resistance
2009
The use of antimicrobials in food animals creates an important source of antimicrobial-resistant bacteria that can spread to humans through the food supply. Improved management of the use of antimicrobials in food animals, particularly reducing the usage of those that are “critically important” for human medicine, is an important step toward preserving the benefits of antimicrobials for people. The World Health Organization has developed and applied criteria to rank antimicrobials according to their relative importance in human medicine. Clinicians, regulatory agencies, policy makers, and other stakeholders can use this ranking when developing risk management strategies for the use of antimicrobials in food production animals. The ranking allows stakeholders to focus risk management efforts on drugs used in food animals that are the most important to human medicine and, thus, need to be addressed most urgently, such as fluoroquinolones, macrolides, and third- and fourth-generation cephalosporins.
Journal Article