Combination antifungal therapy for cryptococcal meningitis

Diagnosis and management of cryptococcal meningitis in HIV-infected adults

Cryptococcal meningitis is a leading cause of morbidity and mortality globally, especially in people with advanced HIV disease. Cryptococcal meningitis is responsible for nearly 20% of all deaths related to advanced HIV disease, with the burden of disease predominantly experienced by people in resource-limited countries. Major advancements in diagnostics have introduced low-cost, easy-to-use antigen tests with remarkably high sensitivity and specificity. These tests have led to improved diagnostic accuracy and are essential for screening campaigns to reduce the burden of cryptococcosis. In the last 5 years, several high-quality, multisite clinical trials have led to innovations in therapeutics that have allowed for simplified regimens, which are better tolerated and result in less intensive monitoring and management of medication adverse effects. One trial found that a shorter, 7-day course of deoxycholate amphotericin B is as effective as the longer 14-day course and that flucytosine is an essential partner drug for reducing mortality in the acute phase of disease. Single-dose liposomal amphotericin B has also been found to be as effective as a 7-day course of deoxycholate amphotericin B. These findings have allowed for simpler and safer treatment regimens that also reduce the burden on the healthcare system. This review provides a detailed discussion of the latest evidence guiding the clinical management and special circumstances that make cryptococcal meningitis uniquely difficult to treat.

Chronic cryptococcal meningitis with a cryptococcoma presenting as normal pressure hydrocephalus: a case report

Chronic meningitis may present with clinical features related to hydrocephalus. We report a 76-year-old female who presented to an outpatient clinic with cognitive decline and gait disturbance with recurrent falls. The initial diagnosis of normal pressure hydrocephalus (NPH) was based on the clinical symptoms and magnetic resonance imaging (MRI) of the brain, which showed ventriculomegaly without an obstructive lesion. During follow-up, however, there was remarkable cognitive decline, and she was unable to walk without assistance. Lumbar puncture and brain MRI showed respective lymphocyte-dominant pleocytosis that was positive for cryptococcal antigen and a new encapsulated abscess-like lesion in a left caudate head. Treatment for cryptococcal meningitis was initiated, and the patient was cured after a long treatment with an antifungal agent. As chronic meningitis could be misdiagnosed as NPH, differential diagnoses of etiologies that can cause hydrocephalus should be addressed.

Proteasome inhibition as a therapeutic target for the fungal pathogen Cryptococcus neoformans

The current therapeutic challenges for treating fungal diseases demand new approaches and new drugs. A promising strategy involves combination therapy with agents of distinct mechanisms of action to increase fungicidal activity and limit the impact of mutations leading to resistance. In this study, we evaluated the antifungal potential of bortezomib by examining the inhibition of proteasome activity, cell proliferation, and capsule production by Cryptococcus neoformans, the causative agent of fungal meningoencephalitis. Chemical genetic screens with collections of deletion mutants identified potential druggable targets for combination therapy with bortezomib. In vitro assays of combinations of bortezomib with flucytosine, chlorpromazine, bafilomycin A1, copper sulfate, or hydroxyurea revealed antifungal effects against C. neoformans. Furthermore, combination treatment with bortezomib and flucytosine in a murine inhalation model of cryptococcosis resulted in the improvement of neurological functions and reduced fungal replication and dissemination, leading to a delay in disease progression. This study therefore highlights the utility of chemical genetic screens to identify new therapeutic approaches as well as the antifungal potential of proteasome inhibition. IMPORTANCE Fungal diseases of humans are difficult to treat, and there is a clear need for additional antifungal drugs, better diagnostics, effective vaccines, and new approaches to deal with emerging drug resistance. Fungi are challenging to control because they share many common biochemical functions with their mammalian hosts and it is therefore difficult to identify fungal-specific targets for drug development. One approach is to employ existing antifungal drugs in combination with agents that target common cellular processes at levels that are (ideally) not toxic for the host. We pursued this approach in this study by examining the potential of the clinically approved proteasome inhibitor bortezomib to influence the proliferation and virulence of Cryptococcus neoformans. We found that the combination of bortezomib with the anti-cryptococcal drug flucytosine improved the survival of infected mice, thus demonstrating the potential of this strategy for antifungal therapy.

Powering up antifungal treatment: using small molecules to unlock the potential of existing therapies

Fungal pathogens are increasingly appreciated as a significant infectious disease challenge. Compared to bacteria, fungal cells are more closely related to human cells, and few classes of antifungal drugs are available. Combination therapy offers a potential solution to reduce the likelihood of resistance acquisition and extend the lifespan of existing antifungals. There has been recent interest in combining first-line drugs with small-molecule adjuvants. In a recent article, Alabi et al. identified 1,4-benzodiazepines as promising molecules to enhance azole activity in pathogenic Candida spp. (P. E. Alabi, C. Gautier, T. P. Murphy, X. Gu, M. Lepas, V. Aimanianda, J. K. Sello, I. V. Ene, 2023, mBio https://doi.org/10.1128/mbio.00479-23). These molecules have no antifungal activity on their own but exhibited significant potentiation of fluconazole in azole-susceptible and -resistant isolates. Additionally, the 1,4-benzodiazepines increased the fungicidal activity of azoles that are typically fungistatic to Candida spp., inhibited filamentation (a virulence-associated trait), and accordingly increased host survival in Galleria mellonella. This research thus provides another encouraging step on the critical pathway toward reducing mortality due to antimicrobial resistance.

New antifungal strategies: drug combination and co-delivery

The growing occurrence of invasive fungal infections and the mounting rates of drug resistance constitute a significant menace to human health. Antifungal drug combinations have garnered substantial interest for their potential to improve therapeutic efficacy, reduce drug doses, reverse, or ameliorate drug resistance. A thorough understanding of the molecular mechanisms underlying antifungal drug resistance and drug combination is key to developing new drug combinations. Here we discuss the mechanisms of antifungal drug resistance and elucidate how to discover potent drug combinations to surmount resistance. We also examine the challenges encountered in developing such combinations and discuss prospects, including advanced drug delivery strategies.

Efficacy of APX2039 in a Rabbit Model of Cryptococcal Meningitis

Cryptococcal Meningitis (CM) is uniformly fatal if not treated, and treatment options are limited. We previously reported on the activity of APX2096, the prodrug of the novel Gwt1 inhibitor APX2039, in a mouse model of CM. Here, we investigated the efficacy of APX2039 in mouse and rabbit models of CM. In the mouse model, the controls had a mean lung fungal burden of 5.95 log10 CFU/g, whereas those in the fluconazole-, amphotericin B-, and APX2039-treated mice were 3.56, 4.59, and 1.50 log10 CFU/g, respectively. In the brain, the control mean fungal burden was 7.97 log10 CFU/g, while the burdens were 4.64, 7.16, and 1.44 log10 CFU/g for treatment with fluconazole, amphotericin B, and APX2039, respectively. In the rabbit model of CM, the oral administration of APX2039 at 50 mg/kg of body weight twice a day (BID) resulted in a rapid decrease in the cerebrospinal fluid (CSF) fungal burden, and the burden was below the limit of detection by day 10 postinfection. The effective fungicidal activity (EFA) was -0.66 log10 CFU/mL/day, decreasing from an average of 4.75 log10 CFU/mL to 0 CFU/mL, over 8 days of therapy, comparing favorably with good clinical outcomes in humans associated with reductions of the CSF fungal burden of -0.4 log10 CFU/mL/day, and, remarkably, 2-fold the EFA of amphotericin B deoxycholate in this model (-0.33 log10 CFU/mL/day). A total drug exposure of the area under the concentration-time curve from 0 to 24 h (AUC0-24) of 25 to 50 mg · h/L of APX2039 resulted in near-maximal antifungal activity. These data support the further preclinical and clinical evaluation of APX2039 as a new oral fungicidal monotherapy for the treatment of CM. IMPORTANCE Cryptococcal meningitis (CM) is a fungal disease with significant global morbidity and mortality. The gepix Gwt1 inhibitors are a new class of antifungal drugs. Here, we demonstrated the efficacy of APX2039, the second member of the gepix class, in rabbit and mouse models of cryptococcal meningitis. We also analyzed the drug levels in the blood and cerebrospinal fluid in the highly predictive rabbit model and built a mathematical model to describe the behavior of the drug with respect to the elimination of the fungal pathogen. We demonstrated that the oral administration of APX2039 resulted in a rapid decrease in the CSF fungal burden, with an effective fungicidal activity of -0.66 log10 CFU/mL/day, comparing favorably with good clinical outcomes in humans associated with reductions of -0.4 log10 CFU/mL/day. The drug APX2039 had good penetration of the central nervous system and is an excellent candidate for future clinical testing in humans for the treatment of CM.

Comparison of amphotericin B deoxycholate in combination with either flucytosine or fluconazole, and voriconazole plus flucytosine for the treatment of HIV-associated cryptococcal meningitis: a prospective multicenter study in China

Background

The most appropriate alternative to induction therapy for HIV-associated cryptococcal meningitis (CM) remains unclear when standard treatment is unavailable, inaccessible, intolerable, or ineffective.

Methods

A prospective, multi-centre cohort study was conducted to analyze the data of 156 HIV-infected patients with CM who were treated with amphotericin B deoxycholate (AmB-D) + flucytosine (5FC), voriconazole (VCZ) + 5FC, or AmB-D + Fluconazole (Flu) as induction regimens. Clinical efficacy, cumulative mortality, and adverse effects were compared among the three treatment groups.

Results

Fewer deaths occurred by week 4 and week 10 among patients receiving AmB-D + 5FC than among those receiving AmB-D + Flu [4 (5.1%) vs. 8 (16.0%) deaths by week 4; hazard ratio, 1.8; 95% confidence interval [CI], 1.0 to 3.3; p = 0.039; and 8 (10.3%) vs. 14 (28.0%) deaths by week 10; hazard ratio, 1.8; 95% CI, 1.1 to 2.7; p = 0.008, respectively]. AmB-D plus 5FC was found to result in significantly higher rates of cerebrospinal fluid (CSF) culture sterility (57.6% vs. 34% by week 2; 87.9% vs. 70% by week 10; p < 0.05 for both comparisons). However, the differences in CSF culture sterility and mortality between the VCZ + 5FC group and the AmB-D + 5FC group were not statistically significant. VCZ plus 5FC had a significantly advantageous effect on the incidence of new AIDS-defining illness and length of hospital stay, compared with AmB-D plus 5FC. Laboratory adverse events (grade 3 or 4), such as severe anemia, were less frequent with VCZ + 5FC use than with AmB-D combined with 5FC or Flu use.

Conclusion

Our results suggest that AmB-D combined with 5FC remains the more efficacious induction regimen compared to AmB-D plus Flu, and that VCZ + 5FC might be a potential alternative when the standard regimen is not readily available, accessible, tolerated, or effective.

Clinical Trials: Registration number, ChiCTR1900021195. Registered 1 February 2019, http://www.chictr.org.cn/showproj.aspx?proj=35362.

Equity in clinical trials for HIV-associated cryptococcal meningitis: A systematic review of global representation and inclusion of patients and researchers

Background

It is essential that clinical trial participants are representative of the population under investigation. Using HIV-associated cryptococcal meningitis (CM) as a case study, we conducted a systematic review of clinical trials to determine how inclusive and representative they were both in terms of the affected population and the involvement of local investigators.

Methods

We searched Medline, EMBASE, Cochrane, Africa-Wide, CINAHL Plus, and Web of Science. Data were extracted for 5 domains: study location and design, screening, participants, researchers, and funders. Data were summarised and compared over 3 time periods: pre-antiretroviral therapy (ART) (pre-2000), early ART (2000 to 2009), and established ART (post-2010) using chi-squared and chi-squared for trend. Comparisons were made with global disease burden estimates and a composite reference derived from observational studies.

Results

Thirty-nine trials published between 1990 and 2019 were included. Earlier studies were predominantly conducted in high-income countries (HICs) and recent studies in low- and middle-income countries (LMICs). Most recent studies occurred in high CM incidence countries, but some highly affected countries have not hosted trials. The sex and ART status of participants matched those of the general CM population. Patients with reduced consciousness and those suffering a CM relapse were underrepresented. Authorship had poor representation of women (29% of all authors), particularly as first and final authors. Compared to trials conducted in HICs, trials conducted in LMICs were more likely to include female authors (32% versus 20% p = 0.014) but less likely to have authors resident in (75% versus 100%, p < 0.001) or nationals (61% versus 93%, p < 0.001) of the trial location.

Conclusions

There has been a marked shift in CM trials over the course of the HIV epidemic. Trials are primarily performed in locations and populations that reflect the burden of disease, but severe and relapse cases are underrepresented. Most CM trials now take place in LMICs, but the research is primarily funded and led by individuals and institutions from HICs.

It is essential that clinical trial participants are representative of the population under investigation. Similarly, research must meaningfully include researchers who are from and/or based in the location where the study is being conducted, both to ensure that the research matches the local need but also to promote equity in research. Using clinical trials in HIV-associated cryptococcal meningitis as a case study, we conducted a systematic review to determine how inclusive and representative trials have been across the course of the HIV epidemic. We identified 39 studies. There was a geographical shift with trials moving from the USA to Africa and Asia over time. We found that recent trials were conducted in areas heavily affected by cryptococcal meningitis, but we did identify geographical areas and patient groups that have been underrepresented. We also found inequality within authorship that was skewed towards male researchers from high-income countries. These findings outline areas for our discipline to focus on. We can also use this study as a benchmark from which to monitor our progress over time. This is a broad methodology that could be adopted and adapted by other research groups.

Antifungal drugs: An updated review of central nervous system pharmacokinetics

Invasive fungal infections (IFIs) in the central nervous system (CNS) are particularly hard to treat and are associated with high morbidity and mortality rates. Four chemical classes of systemic antifungal agents are used for the treatment of IFIs (eg meningitis), including polyenes, triazoles, pyrimidine analogues and echinocandins. This review will address all of these classes and discuss their penetration and accumulation in the CNS. Treatment of fungal meningitis is based on the antifungal that shows good penetration and accumulation in the CNS. Pharmacokinetic data concerning the entry of antifungal agents into the intracranial compartments are faulty. This review will provide an overview of the ability of systemic antifungals to penetrate the CNS, based on previously published drug physicochemical properties and pharmacokinetic data, for evaluation of the most promising antifungal drugs for the treatment of fungal CNS infections. The studies selected and discussed in this review are from 1990 to 2019.

What Is the Most Appropriate Induction Regimen for the Treatment of HIV-Associated Cryptococcal Meningitis When the Recommended Regimen Is Not Available? Evidence From a Network Meta-Analysis

Aims

Our object was to find the most appropriate, most effective, and most readily available of four induction regimens for HIV-associated cryptococcal meningitis (CM) (Regimen A: 1 week of AmB plus 5-FC followed by 1 week of fluconazole, Regimen B: 1 week of AmB plus fluconazole followed by 1 week of fluconazole, Regimen C: 2 weeks of AmB plus 5-FC, Regimen D: 2 weeks of AmB plus fluconazole), given the vast differences between resource-limited and resource-abundant settings regarding therapeutic drug accessibility, availability, and affordability for HIV-associated (CM).

Methods

We conducted a network meta-analysis to compare the therapeutic efficacy and safety of four different induction treatment regimens.

Results

The 10-week mortality of Regimen A was significantly lower than that of Regimen B and D, and the 2-week mortality of Regimen A was significantly lower than that of Regimen B. Furthermore, there were no statistically significant differences in 10-week mortality, 2-week mortality, as well as in effective fungicidal activity (EFA) over the first 2 weeks among Regimens B, C, and D. The statistical differences in adverse events between Regimen B and Regimen D, and Regimen C and Regimen D were not calculated to be significant.

Conclusions

Our results indicate that, 1 week of AmB plus 5-FC followed by 1 week of fluconazole is superior to the three other studied regimens, and that when 5-FC is not available, accessible, or affordable, 2 weeks of AmB plus fluconazole or 1 week of AmB plus fluconazole followed by 1 week of fluconazole is an appropriate substitution for 2 weeks of AmB plus 5-FC.

Evaluation of low cryptococcal antigen titer as determined by the lateral flow assay in serum and cerebrospinal fluid among HIV-negative patients: a retrospective diagnostic accuracy study

Cryptococcosis is one of the most common opportunistic infections in both immunocompetent and immunocompromised hosts. Although the cryptococcal antigen (CrAg) lateral flow assay (LFA) has been widely used in clinical settings due to its high sensitivity and specificity, the diagnostic value of a low CrAg LFA titers remains unclear. In this study, we performed a retrospective analysis of 149 HIV-negative patients with low CrAg LFA titers (≤1:10) in a Chinese tertiary hospital from January 2013 to December 2017, to evaluate the diagnostic value of low CrAg LFA titers in serum and cerebrospinal fluid (CSF) at different thresholds. Sensitivity and specificity of low CrAg LFA titers in patients with definitive diagnoses of cryptococcosis were 39.6% (95% CI, 29.7–50.1%) and 100% (95% CI, 69.2–100%), respectively, at a threshold of 1:10 in serum. A sensitivity of 72.9% (95% CI, 62.9–81.5%) and a decreased specificity of 70.0% (95% CI, 34.8–93.3%) were observed at a threshold of 1:5 in serum. No false-positive cases were identified in patients with low CrAg titers in CSF and all positive predictive values (PPVs) were 100%. Among the cases with low serum CrAg titers, lumbar puncture was performed in 97 patients and positive CSF CrAg titers were reported in 6 patients. In conclusion, the results of this study imply that low CrAg LFA titer, either in serum or CSF, is crucial for early diagnosis of cryptococcosis in HIV-negative patients, and lumbar puncture is recommended to be performed routinely for CSF testing when a positive low serum titer is reported. Cryptococcal meningitis should be considered seriously when the CSF CrAg titer is positive.

Management of HIV-infected patients in the intensive care unit

The widespread use of combination antiretroviral therapies (cART) has converted the prognosis of HIV infection from a rapidly progressive and ultimately fatal disease to a chronic condition with limited impact on life expectancy. Yet, HIV-infected patients remain at high risk for critical illness due to the occurrence of severe opportunistic infections in those with advanced immunosuppression (i.e., inaugural admissions or limited access to cART), a pronounced susceptibility to bacterial sepsis and tuberculosis at every stage of HIV infection, and a rising prevalence of underlying comorbidities such as chronic obstructive pulmonary diseases, atherosclerosis or non-AIDS-defining neoplasms in cART-treated patients aging with controlled viral replication. Several patterns of intensive care have markedly evolved in this patient population over the late cART era, including a steady decline in AIDS-related admissions, an opposite trend in admissions for exacerbated comorbidities, the emergence of additional drivers of immunosuppression (e.g., anti-neoplastic chemotherapy or solid organ transplantation), the management of cART in the acute phase of critical illness, and a dramatic progress in short-term survival that mainly results from general advances in intensive care practices. Besides, there is a lack of data regarding other features of ICU and post-ICU care in these patients, especially on the impact of sociological factors on clinical presentation and prognosis, the optimal timing of cART introduction in AIDS-related admissions, determinants of end-of-life decisions, long-term survival, and functional outcomes. In this narrative review, we sought to depict the current evidence regarding the management of HIV-infected patients admitted to the intensive care unit.

Hope on the Horizon: Novel Fungal Treatments in Development

The treatment of invasive fungal infections remains challenging due to limitations in currently available antifungal therapies including toxicity, interactions, restricted routes of administration, and drug resistance. This review focuses on novel therapies in clinical development, including drugs and a device. These drugs have novel mechanisms of action to overcome resistance, and some offer new formulations providing distinct advantages over current therapies to improve safety profiles and reduce interactions. Among agents that target the cell wall, 2 glucan synthesis inhibitors are discussed (rezafungin and ibrexafungerp), as well as fosmanogepix and nikkomycin Z. Agents that target the cell membrane include 3 fourth-generation azoles, oral encochleated amphotericin B, and aureobasidin A. Among agents with intracellular targets, we will review olorofim, VL-2397, T-2307, AR-12, and MGCD290. In addition, we will describe neurapheresis, a device used as adjunctive therapy for cryptococcosis. With a field full of novel treatments for fungal infections, the future looks promising.

Mortality from HIV-associated meningitis in sub-Saharan Africa: a systematic review and meta-analysis

INTRODUCTION

HIV-associated cryptococcal, TB and pneumococcal meningitis are the leading causes of adult meningitis in sub-Saharan Africa (SSA). We performed a systematic review and meta-analysis with the primary aim of estimating mortality from major causes of adult meningitis in routine care settings, and to contrast this with outcomes from clinical trial settings.

METHODS

We searched PubMed, EMBASE and the Cochrane Library for published clinical trials (defined as randomized-controlled trials (RCTs) or investigator-managed prospective cohorts) and observational studies that evaluated outcomes of adult meningitis in SSA from 1 January 1990 through 15 September 2019. We performed random effects modelling to estimate pooled mortality, both in clinical trial and routine care settings. Outcomes were stratified as short-term (in-hospital or two weeks), medium-term (up to 10 weeks) and long-term (up to six months).

RESULTS AND DISCUSSION

Seventy-nine studies met inclusion criteria. In routine care settings, pooled short-term mortality from cryptococcal meningitis was 44% (95% confidence interval (95% CI):39% to 49%, 40 studies), which did not differ between amphotericin (either alone or with fluconazole) and fluconazole-based induction regimens, and was twofold higher than pooled mortality in clinical trials using amphotericin based treatment (21% (95% CI:17% to 25%), 17 studies). Pooled short-term mortality of TB meningitis was 46% (95% CI: 33% to 59%, 11 studies, all routine care). For pneumococcal meningitis, pooled short-term mortality was 54% in routine care settings (95% CI:44% to 64%, nine studies), with similar mortality reported in two included randomized-controlled trials. Few studies evaluated long-term outcomes.

CONCLUSIONS

Mortality rates from HIV-associated meningitis in SSA are very high under routine care conditions. Better strategies are needed to reduce mortality from HIV-associated meningitis in the region.

A Highly Active Triterpene Derivative Capable |of Biofilm Damage to Control Cryptococcus spp

Cryptococcus neoformans is an encapsulated yeast responsible for more than 180,000 deaths per year. The standard therapeutic approach against cryptococcosis is a combination of amphotericin B with flucytosine. In countries where cryptococcosis is most prevalent, 5-fluorocytosine is rarely available, and amphotericin B requires intravenous administration. C. neoformans biofilm formation is related to increased drug resistance, which is an important outcome for hospitalized patients. Here, we describe new molecules with anti-cryptococcal activity. A collection of 66 semisynthetic derivatives of ursolic acid and betulinic acid was tested against mature biofilms of C. neoformans at 25 µM. Out of these, eight derivatives including terpenes, benzazoles, flavonoids, and quinolines were able to cause damage and eradicate mature biofilms. Four terpene compounds demonstrated significative growth inhibition of C. neoformans. Our study identified a pentacyclic triterpenoid derived from betulinic acid (LAFIS13) as a potential drug for anti-cryptococcal treatment. This compound appears to be highly active with low toxicity at minimal inhibitory concentration and capable of biofilm eradication.

Synergistic antifungal interactions of amphotericin B with 4-(5-methyl-1,3,4-thiadiazole-2-yl) benzene-1,3-diol

Amphotericin B (AmB) is a very potent antifungal drug with very rare resistance among clinical isolates. Treatment with the AmB formulations available currently is associated with severe side effects. A promising strategy to minimize the toxicity of AmB is reducing its dose by combination therapy with other antifungals, showing synergistic interactions. Therefore, substances that display synergistic interactions with AmB are still being searched for. Screening tests carried out on several dozen of synthetic 1,3,4-thiadiazole derivatives allowed selection of a compound called 4-(5-methyl-1,3,4-thiadiazole-2-yl) benzene-1,3-diol (abbreviated as C1), which shows strong synergistic interaction with AmB and low toxicity towards human cells. The aim of the present study was to investigate the type of in vitro antifungal interactions of the C1 compound with AmB against fungal clinical isolates differing in susceptibility. The results presented in the present paper indicate that the C1 derivative shows strong synergistic interaction with AmB, which allows the use of a dozen to several dozen times lower AmB concentration necessary for 100% inhibition of the growth of pathogenic fungi in vitro. Synergistic interactions were noted for all tested strains, including strains with reduced sensitivity to AmB and azole-resistant isolates. These observations give hope for the possibility of application of the AmB - C1 combinatory therapy in the treatment of fungal infections.

Development of nose-to-brain delivery of ketoconazole by nanostructured lipid carriers against cryptococcal meningoencephalitis in mice

Cryptococcus neoformans-mediated meningoencephalitis is a critical infectious disorder of the human central nervous system. However, efficient treatment for the disease is limited due to the poor penetration across the blood brain barrier (BBB). Here, we develop a nose-to-brain drug delivery system utilizing nanostructured lipid carriers (NLCs). We demonstrated that fluorescent-dye-loaded NLCs efficiently uptake into the cytoplasm of encapsulated C. neoformans cells. In comparison with current antifungal drugs, the ketoconazole (keto)-NLCs show significantly increased antifungal activity against C. neoformans in vivo under various growth conditions. The NLCs show enhanced tissue colonization properties. Importantly, using animal imaging analyses, NLCs are able to enter brain tissues via the olfactory bulb region by intranasal administration, bypassing the BBB. In addition, NLCs maintain prolonged residence in tissues. In mouse brain tissue, keto-NLCs showed significantly enhanced antifungal activity when administered intranasally, drastically dampening the C. neoformans burden. Taken together, NLCs not only improve the ketoconazole penetration efficiency against capsulated C. neoformans cells, but also boost the efficacy of antifungal drugs. Most importantly, keto-NLCs significantly contribute to the treatment of cryptococcal meningoencephalitis in mice by bypassing the BBB via the olfactory system.

AMBIsome Therapy Induction OptimisatioN (AMBITION): High Dose AmBisome for Cryptococcal Meningitis Induction Therapy in sub-Saharan Africa: Study Protocol for a Phase 3 Randomised Controlled Non-Inferiority Trial

BACKGROUND

Cryptococcal meningitis (CM) is a major cause of mortality in HIV programmes in Africa despite increasing access to antiretroviral therapy (ART). Mortality is driven in part by limited availability of amphotericin-based treatment, drug-induced toxicities of amphotericin B deoxycholate and prolonged hospital admissions. A single, high-dose of liposomal amphotericin (L-AmB, Ambisome) on a fluconazole backbone has been reported as non-inferior to 14 days of standard dose L-AmB in reducing fungal burden. This trial examines whether single, high-dose L-AmB given with high-dose fluconazole and flucytosine is non-inferior to a seven-day course of amphotericin B deoxycholate plus flucytosine (the current World Health Organization [WHO] recommended treatment regimen).

METHODS

An open-label phase III randomised controlled non-inferiority trial conducted in five countries in sub-Saharan Africa: Botswana, Malawi, South Africa, Uganda and Zimbabwe. The trial will compare CM induction therapy with (1) a single dose (10 mg/kg) of L-AmB given with 14 days of fluconazole (1200 mg/day) and flucytosine (100 mg/kg/day) to (2) seven days amphotericin B deoxycholate (1 mg/kg/day) given alongside seven days of flucytosine (100 mg/kg/day) followed by seven days of fluconazole (1200 mg/day). The primary endpoint is all-cause mortality at ten weeks with a non-inferiority margin of 10% and 90% power. Secondary endpoints are early fungicidal activity, proportion of grade III/IV adverse events, pharmacokinetic parameters and pharmacokinetic/pharmacodynamic associations, health service costs, all-cause mortality within the first two and four weeks, all-cause mortality within the first ten weeks (superiority analysis) and rates of CM relapse, immune reconstitution inflammatory syndrome and disability at ten weeks. A total of 850 patients aged ≥ 18 years with a first episode of HIV-associated CM will be enrolled (425 randomised to each arm). All patients will be followed for 16 weeks. All patients will receive consolidation therapy with fluconazole 800 mg/day to complete ten weeks of treatment, followed by fluconazole maintenance and ART as per local guidance.

DISCUSSION

A safe, sustainable and easy to administer regimen of L-AmB that is non-inferior to seven days of daily amphotericin B deoxycholate therapy may reduce the number of adverse events seen in patients treated with amphotericin B deoxycholate and shorten hospital admissions, providing a highly favourable and implementable alternative to the current WHO recommended first-line treatment.

TRIAL REGISTRATION

ISRCTN, ISRCTN72509687 . Registered on 13 July 2017.

Discovering a new class of antifungal agents that selectively inhibits microbial carbonic anhydrases

Infections caused by pathogens resistant to the available antimicrobial treatments represent nowadays a threat to global public health. Recently, it has been demonstrated that carbonic anhydrases (CAs) are essential for the growth of many pathogens and their inhibition leads to growth defects. Principal drawbacks in using CA inhibitors (CAIs) as antimicrobial agents are the side effects due to the lack of selectivity toward human CA isoforms. Herein we report a new class of CAIs, which preferentially interacts with microbial CA active sites over the human ones. The mechanism of action of these inhibitors was investigated against an important fungal pathogen, Cryptococcus neoformans, revealing that they are also able to inhibit CA in microbial cells growing in vitro. At our best knowledge, this is the first report on newly designed synthetic compounds selectively targeting β-CAs and provides a proof of concept of microbial CAs suitability as an antimicrobial drug target.

Central Nervous System Vasculitis for Cryptococcosis in an Immunocompetent Patient

Cryptococcal meningitis is a life-threatening condition caused by a fungal pathogen, Cryptococcus neoformans, that can infect both immunosuppressed and immunocompetent hosts. It is an important cause of morbidity and mortality in severely immunodeficient patients. However, in an immunocompetent patient it represents a diagnostic challenge, mainly because it is extremely rare, but also because of its nonspecific clinical manifestation. Neurovascular involvement in cryptococcal meningitis is rare and not well known and only few reports have described this association. We describe a cryptococcal meningitis in an immunocompetent patient associated with central nervous system vasculitis.

Peeling the onion: the outer layers of Cryptococcus neoformans

Cryptococcus neoformans is an opportunistic fungal pathogen that is ubiquitous in the environment. It causes a deadly meningitis that is responsible for over 180,000 deaths worldwide each year, including 15% of all AIDS-related deaths. The high mortality rates for this infection, even with treatment, suggest a need for improved therapy. Unique characteristics of C. neoformans may suggest directions for drug discovery. These include features of three structures that surround the cell: the plasma membrane, the cell wall around it, and the outermost polysaccharide capsule. We review current knowledge of the fundamental biology of these fascinating structures and highlight open questions in the field, with the goal of stimulating further investigation that will advance basic knowledge and human health.

Activity of VT-1129 against Cryptococcus neoformans clinical isolates with high fluconazole MICs

Although antifungal drug resistance in the human fungal pathogen Cryptococcus neoformans is relatively uncommon, fluconazole-resistant strains are problematic for preemptive treatment of cryptococcal antigenemia or during cryptococcal meningitis consolidation therapy. We analyzed activity of the experimental antifungal VT-1129 on 51 clinical Cryptococcus neoformans isolates previously screened for fluconazole resistance; with an emphasis on fluconazole dose-dependent (MIC 16-32 μg/ml) or resistant (MIC ≥ 64 μg/ml) isolates. Overall, the VT-1129 geometric mean MIC was 0.027 μg/ml. The VT-1129 MIC50 was 0.05 μg/ml and 0.25 μg/ml for dose-dependent (n = 27) and resistant isolates (n = 6), respectively. These data suggest VT-1129 shows potential for use against fluconazole-resistant Cryptococcus.

Pharmacokinetics of antifungal drugs: practical implications for optimized treatment of patients

Introduction

Because of the high mortality of invasive fungal infections (IFIs), appropriate exposure to antifungals appears to be crucial for therapeutic efficacy and safety.

Materials and methods

This review summarises published pharmacokinetic data on systemically administered antifungals focusing on co-morbidities, target-site penetration, and combination antifungal therapy.

Conclusions and discussion

Amphotericin B is eliminated unchanged via urine and faeces. Flucytosine and fluconazole display low protein binding and are eliminated by the kidney. Itraconazole, voriconazole, posaconazole and isavuconazole are metabolised in the liver. Azoles are substrates and inhibitors of cytochrome P450 (CYP) isoenzymes and are therefore involved in numerous drug–drug interactions. Anidulafungin is spontaneously degraded in the plasma. Caspofungin and micafungin undergo enzymatic metabolism in the liver, which is independent of CYP. Although several drug–drug interactions occur during caspofungin and micafungin treatment, echinocandins display a lower potential for drug–drug interactions. Flucytosine and azoles penetrate into most of relevant tissues. Amphotericin B accumulates in the liver and in the spleen. Its concentrations in lung and kidney are intermediate and relatively low myocardium and brain. Tissue distribution of echinocandins is similar to that of amphotericin. Combination antifungal therapy is established for cryptococcosis but controversial in other IFIs such as invasive aspergillosis and mucormycosis.

Experimental Models of Short Courses of Liposomal Amphotericin B for Induction Therapy for Cryptococcal Meningitis

Cryptococcal meningoencephalitis is a rapidly lethal infection in immunocompromised patients. Induction regimens are usually administered for 2 weeks. The shortest effective period of induction therapy with liposomal amphotericin B (LAMB) is unknown. The pharmacodynamics of LAMB were studied in murine and rabbit models of cryptococcal meningoencephalitis. The concentrations of LAMB in the plasma and brains of mice were measured using high-performance liquid chromatography (HPLC). Histopathological changes were determined. The penetration of LAMB into the brain was determined by immunohistochemistry using an antibody directed to amphotericin B. A dose-dependent decline in fungal burden was observed in the brains of mice, with near-maximal efficacy achieved with LAMB at 10 to 20 mg/kg/day. The terminal elimination half-life in the brain was 133 h. The pharmacodynamics of a single dose of 20 mg/kg was the same as that of 20 mg/kg/day administered for 2 weeks. Changes in quantitative counts were reflected by histopathological changes in the brain. Three doses of LAMB at 5 mg/kg/day in rabbits were required to achieve fungicidal activity in cerebrospinal fluid (cumulative area under the concentration-time curve, 2,500 mg · h/liter). Amphotericin B was visible in the intra- and perivascular spaces, the leptomeninges, and the choroid plexus. The prolonged mean residence time of amphotericin B in the brain suggests that abbreviated induction regimens of LAMB are possible for cryptococcal meningoencephalitis.

Factors associated with early mycological clearance in HIV-associated cryptococcal meningitis

INTRODUCTION

The first-line combination therapy for HIV-associated cryptococcal meningitis (CM), a condition of high mortality particularly in the first two weeks of treatment, consists of amphotericin B plus flucytosine (5-FC). Given that 5-FC remains unavailable in many countries, the knowledge of factors influencing mycological clearance in patients treated with second-line therapy could contribute to effective management.

OBJECTIVES

To determine the factors associated with the clearance of Cryptococcus sp. from the cerebrospinal fluid by the second week of effective antifungal therapy (early mycological clearance) in HIV-associated CM.

METHODS

Retrospective cohort study based on secondary data corresponding to HIV-associated CM cases hospitalized at a tertiary health care center in Lima, Peru where 5-FC remains unavailable. Risk factors associated with early mycological clearance were analyzed by generalized linear regression models.

RESULTS

From January 2000 to December 2013, 234 individuals were discharged with a diagnosis of HIV-associated CM; in 215 we retrieved the required data. The inpatient mortality was 20% (43/215), 15 of them in the first two weeks of treatment. In the final model (157 cases), adjusted for age, previous episode of CM, ART use, type of antifungal treatment, raised intracranial pressure, frequency of therapeutic lumbar punctures, baseline fungal burden and treatment period, the factors associated with early mycological clearance were: Amphotericin B deoxycholate plus fluconazole as combination therapy (RR, 1.56; 95% CI, 1.14-2.14); severe baseline intracranial pressure (≥35 cm H2O) (RR, 0.57; 95% CI, 0.33-0.99); and baseline fungal burden over 4.5 log10 CFU/mL (RR, 0.61 95% CI: 0.39-0.95).

CONCLUSIONS

In a setting without access to first-line therapy for CM, the combination therapy with amphotericin B deoxycholate plus fluconazole was positively associated with early mycological clearance, while high fungal burden and severe baseline intracranial pressure were negatively associated, and thus related to failure.

Systemic Antifungal Agents: Current Status and Projected Future Developments

By definition, an antifungal agent is a drug that selectively destroys fungal pathogens with minimal side effects to the host. Despite an increase in the prevalence of fungal infections particularly in immunocompromised patients, only a few classes of antifungal drugs are available for therapy, and they exhibit limited efficacy in the treatment of life-threatening infections. These drugs include polyenes, azoles, echinocandins, and nucleoside analogs. This chapter focuses on the currently available classes and representatives of systemic antifungal drugs in clinical use. We further discuss the unmet clinical needs in the antifungal research field; efforts in reformulation of available drugs such as Amphotericin B nanoparticles for oral drug delivery; development of new agents of known antifungal drug classes, such as albaconazole, SCY-078, and biafungin; and new drugs with novel targets for treatment of invasive fungal infections, including nikkomycin Z, sordarin derivatives, VT-1161 and VT-1129, F901318, VL-2397, and T-2307.

Liposomal Amphotericin B (AmBisome(®)): A Review of the Pharmacokinetics, Pharmacodynamics, Clinical Experience and Future Directions

Liposomal amphotericin B (AmBisome(®); LAmB) is a unique lipid formulation of amphotericin B. LAmB is a standard of care for a wide range of medically important opportunistic fungal pathogens. LAmB has a significantly improved toxicity profile compared with conventional amphotericin B deoxycholate (DAmB). Despite nearly 20 years of clinical use, the pharmacokinetics and pharmacodynamics of this agent, which differ considerably from DAmB, remain relatively poorly understood and underutilized in the clinical setting. The molecular pharmacology, preclinical and clinical pharmacokinetics, and clinical experience with LAmB for the most commonly encountered fungal pathogens are reviewed. In vitro, experimental animal models and human clinical trial data are summarized, and novel routes of administration and dosing schedules are discussed. LAmB is a formulation that results in reduced toxicity as compared with DAmB while retaining the antifungal effect of the active agent. Its long terminal half-life and retention in tissues suggest that single or intermittent dosing regimens are feasible, and these should be actively investigated in both preclinical models and in clinical trials. Significant gaps remain in knowledge of pharmacokinetics and pharmacodynamics in special populations such as neonates and children, pregnant women and obese patients.

Early Fungicidal Activity as a Candidate Surrogate Endpoint for All-Cause Mortality in Cryptococcal Meningitis: A Systematic Review of the Evidence

BACKGROUND

Cryptococcal meningitis (CM) is a leading cause of HIV-associated mortality. In clinical trials evaluating treatments for CM, biomarkers of early fungicidal activity (EFA) in cerebrospinal fluid (CSF) have been proposed as candidate surrogate endpoints for all- cause mortality (ACM). However, there has been no systematic evaluation of the group-level or trial-level evidence for EFA as a candidate surrogate endpoint for ACM.

METHODS

We conducted a systematic review of randomized trials in treatment of CM to evaluate available evidence for EFA measured as culture negativity at 2 weeks/10 weeks and slope of EFA as candidate surrogate endpoints for ACM. We performed sensitivity analysis on superiority trials and high quality trials as determined by Cochrane measures of trial bias.

RESULTS

Twenty-seven trials including 2854 patients met inclusion criteria. Mean ACM was 15.8% at 2 weeks and 27.0% at 10 weeks with no overall significant difference between test and control groups. There was a statistically significant group-level correlation between average EFA and ACM at 10 weeks but not at 2 weeks. There was also no statistically significant group-level correlation between CFU culture negativity at 2weeks/10weeks or average EFA slope at 10 weeks. A statistically significant trial-level correlation was identified between EFA slope and ACM at 2 weeks, but is likely misleading, as there was no treatment effect on ACM.

CONCLUSIONS

Mortality remains high in short time periods in CM clinical trials. Using published data and Institute of Medicine criteria, evidence for use of EFA as a surrogate endpoint for ACM is insufficient and could provide misleading results from clinical trials. ACM should be used as a primary endpoint evaluating treatments for cryptococcal meningitis.

Cryptococcal Disease in HIV-Infected Children

Cryptococcus neoformans is an encapsulated fungal pathogen that is remarkable for its tendency to cause meningoencephalitis, especially in patients with AIDS. While disease is less common in children than adults, it remains an important cause of morbidity and mortality among HIV-infected children without access to anti-retroviral therapy. This review highlights recent insights into both the biology and treatment of cryptococcosis with a special emphasis on the pediatric literature.

Favorable Evolution of Cryptococcal Meningitis in the Context of Flucytosine Resistance

Cryptococcal meningitis is a critical illness affecting 0.2% to 5% solid-organ transplant recipients with a 40% to 50% mortality. We report the case of a 48-year-old lung transplant recipient, who, 15 months after a right lung graft, kept parakeets and developed meningitis due to Cryptococcus neoformans. Immunosuppressive treatment was based on a quadruple sequential immunosuppressive therapy that included induction therapy with thymoglobulin, followed by corticosteroids, calcineurin inhibitors, and mycophenolate mofetil. Antifungal susceptibility testing of Cryptococcus neoformans showed resistance to flucytosine and intermediate sensitivity to fluconazole. Initial treatment adhered to international guidelines; however, the patient could not tolerate an effective double-antifungal therapy during the first 2 months of treatment. Despite this delayed treatment for an aggressive infection in an immunocompromised patient, the patient survived without relapse and received maintenance treatment with fluconazole during the course of 3 years. Administration of calcineurin inhibitors as immunosuppressive treatment may partly explain this outcome, as this therapeutic class is known to protect from severe forms of cryptococcal meningitis.

HIV-Associated Cryptococcal Meningitis: Bridging the Gap Between Developed and Resource-Limited Settings

Cryptococcal meningitis is a major cause of HIV-associated morbidity and mortality worldwide. Most cases occur in low-income countries, where over half of patients die within 10 weeks of diagnosis compared to as few as 10 % of patients from developed countries. A host of factors, spanning the HIV care continuum, are responsible for this gap in treatment outcomes between developed and resource-limited settings. We explore factors responsible for this outcomes gap and describe low-cost, highly effective measures that can be implemented immediately to improve outcomes in resource-limited settings. We also explore health-system challenges that must be addressed to reduce mortality further, recent research in disease prevention, and novel short-course treatment regimens that, if efficacious, could be implemented in resource-limited settings where the cost of standard treatment regimens is currently prohibitive.

Post-infectious inflammatory response syndrome (PIIRS): Dissociation of T-cell-macrophage signaling in previously healthy individuals with cryptococcal fungal meningoencephalitis

Cryptococcus is an important cause of central nervous system infections in both immunocompromised patients such as those with HIV/AIDS as well as previously healthy individuals. Deficiencies in T-cell activation are well-known to be highly associated with host susceptibility in HIV/AIDS as well in animal modeling studies, resulting in poor microbiological control and little host inflammation. However, recent studies conducted in human patients have demonstrated roles for macrophage signaling defects as an important association with disease susceptibility. For example, an autoantibody to granulocyte monocyte stimulating factor (GMCSF) resulted in defective STAT5 signaling and susceptibility to cryptococcosis. In addition, severe cases of cryptococcal meningo-encephalitis in previously healthy patients, with or without anti-GMCSF autoantibody, developed a highly activated intrathecal T-cell population but had defects in effective macrophage polarization. Intrathecal inflammation correlated with neurological damage, measured by the axonal damage protein, neurofilament light chain 1. Based on these studies, we propose a new syndrome of cryptococcal post-infectious inflammatory response syndrome (PIIRS) defined in previously healthy patients with cryptococcal meningo-encephalitis as the presence of a poor clinical response in the setting of at least 1 month of amphotericin-based fungicidal therapy and sterile cerebrospinal cultures. These findings are discussed in light of the potential for improving therapy.

Analysis of cerebrospinal fluid protein concentrations of patients with cryptococcal meningitis treated with antifungal agents

BACKGROUND

Many neurological diseases are accompanied by an increase in the cerebrospinal fluid (CSF) protein concentration, which indicates dysfunction of the blood-CSF/blood-brain barrier. However, the significance CSF protein concentration of patients with cryptococcal meningitis (CM) is not fully understood. The aim of the present was to determine whether CSF protein concentrations correlated with the responses of patients to treatment with antifungal drugs.

METHODS

We conducted a retrospective study of the analytical data of 623 lumbar punctures of 46 patients with CM who were treated at West China Hospital. We divided the patients into groups with good or poor responses to antifungal treatment. We used a generalized linear mixed model (GLMM) to evaluate the significance of the differences between the two groups.

RESULTS

The baseline CSF protein concentrations of the good antifungal response group (GR-group) (median = 0.97 g/L) were higher compared with those of the poor antifungal response group (PR-group) (median = 0.72 g/L). Analysis using the GLMM indicated that the CSF protein concentration of the GR-group decreased at a rate of 1.8 mg/L per day after antifungal treatment started and was 2.1 mg/L higher compared with that of the PR-group.

CONCLUSIONS

Compared with poor responders, we found that the baseline CSF protein concentrations of good responders were higher and decreased at faster rate after the initiation of antifungal treatment.

Methods of rapid diagnosis for the etiology of meningitis in adults

Infectious meningitis may be due to bacterial, mycobacterial, fungal or viral agents. Diagnosis of meningitis must take into account numerous items of patient history and symptomatology along with regional epidemiology and basic cerebrospinal fluid testing (protein, etc.) to allow the clinician to stratify the likelihood of etiology possibilities and rationally select additional diagnostic tests. Culture is the mainstay for diagnosis in many cases, but technology is evolving to provide more rapid, reliable diagnosis. The cryptococcal antigen lateral flow assay (Immuno-Mycologics) has revolutionized diagnosis of cryptococcosis and automated nucleic acid amplification assays hold promise for improving diagnosis of bacterial and mycobacterial meningitis. This review will focus on a holistic approach to diagnosis of meningitis as well as recent technological advances.

Cryptococcal Meningitis: Diagnosis and Management Update

Recent advances in the diagnosis and management of cryptococcal meningitis are promising and have been improving long-term survival. Point of care testing has made diagnosing cryptococcal meningitis rapid, practical, and affordable. Targeted screening and treatment programs for cryptococcal antigenemia are a cost effective method for reducing early mortality on antiretroviral therapy (ART). Optimal initial management with amphotericin and flucytosine improves survival against alternative therapies, although amphotericin is difficult to administer and flucytosine is not available in middle or low income countries, where cryptococcal meningitis is most prevalent. Controlling increased intracranial pressure with serial therapeutic lumbar punctures has a proven survival benefit. Delaying ART initiation for 4 weeks after the diagnosis of cryptococcal meningitis is associated with improved survival. Fortunately, new approaches have been leading the way toward improving care for cryptococcal meningitis patients. New trials utilizing different combinations of antifungal therapy are reviewed, and we summarize the efficacy of different regimens.

Paradoxical Immune Responses in Non-HIV Cryptococcal Meningitis

The fungus Cryptococcus is a major cause of meningoencephalitis in HIV-infected as well as HIV-uninfected individuals with mortalities in developed countries of 20% and 30%, respectively. In HIV-related disease, defects in T-cell immunity are paramount, whereas there is little understanding of mechanisms of susceptibility in non-HIV related disease, especially that occurring in previously healthy adults. The present description is the first detailed immunological study of non-HIV-infected patients including those with severe central nervous system (s-CNS) disease to 1) identify mechanisms of susceptibility as well as 2) understand mechanisms underlying severe disease. Despite the expectation that, as in HIV, T-cell immunity would be deficient in such patients, cerebrospinal fluid (CSF) immunophenotyping, T-cell activation studies, soluble cytokine mapping and tissue cellular phenotyping demonstrated that patients with s-CNS disease had effective microbiological control, but displayed strong intrathecal expansion and activation of cells of both the innate and adaptive immunity including HLA-DR+ CD4+ and CD8+ cells and NK cells. These expanded CSF T cells were enriched for cryptococcal-antigen specific CD4+ cells and expressed high levels of IFN-γ as well as a lack of elevated CSF levels of typical T-cell specific Th2 cytokines -- IL-4 and IL-13. This inflammatory response was accompanied by elevated levels of CSF NFL, a marker of axonal damage, consistent with ongoing neurological damage. However, while tissue macrophage recruitment to the site of infection was intact, polarization studies of brain biopsy and autopsy specimens demonstrated an M2 macrophage polarization and poor phagocytosis of fungal cells. These studies thus expand the paradigm for cryptococcal disease susceptibility to include a prominent role for macrophage activation defects and suggest a spectrum of disease whereby severe neurological disease is characterized by immune-mediated host cell damage.

Cryptococcus is an important cause of fungal meningitis with significant mortality globally. Susceptibility to the fungus in humans has been related to T-lymphocyte defects in HIV-infected individuals, but little is known about possible immune defects in non HIV-infected patients including previously healthy individuals. This latter group also has some of the worst response rates to therapy with almost a third dying in the United States, despite available therapy. Here we conducted the first detailed immunological analysis of non-HIV apparently immunocompetent individuals with active cryptococcal disease. In contrast to HIV-infected individuals, these studies identified a highly activated antigen-presenting dendritic cell population within CSF, accompanied by a highly active T-lymphocyte population with potentially damaging inflammatory cytokine responses. Furthermore, elevated levels of CSF neurofilament light chains (NFL), a marker of axonal damage in severe central nervous system infections suggest a dysfunctional role to this acute inflammatory state. Paradoxically, CSF macrophage proportions were reduced in patients with severe disease and biopsy and autopsy samples identified alternatively activated tissue macrophage populations that failed to appropriately phagocytose fungal cells. Our study thus provides new insights into the susceptibility to human cryptococcal disease and identifies a paradoxically active T-lymphocyte response that may be amenable to adjunctive immunomodulation to improve treatment outcomes in this high-mortality disease.

Opportunistic infections and immune reconstitution inflammatory syndrome in HIV-1-infected adults in the combined antiretroviral therapy era: a comprehensive review

Despite the availability of effective combined antiretroviral treatment, many patients still present with advanced HIV infection, often accompanied by an AIDS-defining disease. A subgroup of patients starting antiretroviral treatment under these clinical conditions may experience paradoxical worsening of their disease as a result of an exaggerated immune response towards an active (but also subclinical) infectious agent, despite an appropriate virological and immunological response to the treatment. This clinical condition, known as immune reconstitution inflammatory syndrome, may cause significant morbidity and even mortality if it is not promptly recognized and treated. This review updates current knowledge about the incidence, diagnostic criteria, risk factors, clinical manifestations, and management of opportunistic infections and immune reconstitution inflammatory syndrome in the combined antiretroviral treatment era.

Unraveling the biology of a fungal meningitis pathogen using chemical genetics

The fungal meningitis pathogen Cryptococcus neoformans is a central driver of mortality in HIV/AIDS. We report a genome-scale chemical genetic data map for this pathogen that quantifies the impact of 439 small-molecule challenges on 1,448 gene knockouts. We identified chemical phenotypes for 83% of mutants screened and at least one genetic response for each compound. C. neoformans chemical-genetic responses are largely distinct from orthologous published profiles of Saccharomyces cerevisiae, demonstrating the importance of pathogen-centered studies. We used the chemical-genetic matrix to predict novel pathogenicity genes, infer compound mode of action, and to develop an algorithm, O2M, that predicts antifungal synergies. These predictions were experimentally validated, thereby identifying virulence genes, a molecule that triggers G2/M arrest and inhibits the Cdc25 phosphatase, and many compounds that synergize with the antifungal drug fluconazole. Our work establishes a chemical-genetic foundation for approaching an infection responsible for greater than one-third of AIDS-related deaths.

Mitigation of human-pathogenic fungi that exhibit resistance to medical agents: can clinical antifungal stewardship help?

Reducing indiscriminate antimicrobial usage to combat the expansion of multidrug-resistant human-pathogenic bacteria is fundamental to clinical antibiotic stewardship. In contrast to bacteria, fungal resistance traits are not understood to be propagated via mobile genetic elements, and it has been proposed that a global explosion of resistance to medical antifungals is therefore unlikely. Clinical antifungal stewardship has focused instead on reducing the drug toxicity and high costs associated with medical agents. Mitigating the problem of human-pathogenic fungi that exhibit resistance to antimicrobials is an emergent issue. This article addresses the extent to which clinical antifungal stewardship could influence the scale and epidemiology of resistance to medical antifungals both now and in the future. The importance of uncharted selection pressure exerted by agents outside the clinical setting (agricultural pesticides, industrial xenobiotics, biocides, pharmaceutical waste and others) on environmentally ubiquitous spore-forming molds that are lesserstudied but increasingly responsible for drug-refractory infections is considered.

CryptoDex: a randomised, double-blind, placebo-controlled phase III trial of adjunctive dexamethasone in HIV-infected adults with cryptococcal meningitis: study protocol for a randomised control trial

BACKGROUND

Cryptococcal meningitis (CM) is a severe AIDS-defining illness with 90-day case mortality as high as 70% in sub-Saharan Africa, despite treatment. It is the leading cause of death in HIV patients in Asia and Africa.No major advance has been made in the treatment of CM since the 1970s. The mainstays of induction therapy are amphotericin B and flucytosine, but these are often poorly available where the disease burden is highest. Adjunctive treatments, such as dexamethasone, have had dramatic effects on mortality in other neurologic infections, but are untested in CM. Given the high death rates in patients receiving current optimal treatment, and the lack of new agents on the horizon, adjuvant treatments, which offer the potential to reduce mortality in CM, should be tested.The principal research question posed by this study is as follows: does adding dexamethasone to standard antifungal therapy for CM reduce mortality? Dexamethasone is a cheap, readily available, and practicable intervention.

METHOD

A double-blind placebo-controlled trial with parallel arms in which patients are randomised to receive either dexamethasone or placebo, in addition to local standard of care. The study recruits patients in both Asia and Africa to ensure the relevance of its results to the populations in which the disease burden is highest. The 10-week mortality risk in the control group is expected to be between 30% and 50%, depending on location, and the target hazard ratio of 0.7 corresponds to absolute risk reductions in mortality from 30% to 22%, or from 50% to 38%. Assuming an overall 10-week mortality of at least 30% in our study population, recruitment of 824 patients will be sufficient to observe the expected number of deaths. Allowing for some loss to follow-up, the total sample size for this study is 880 patients. To generate robust evidence across both continents, we aim to recruit roughly similar numbers of patients from each continent. The primary end point is 10-week mortality. Ethical approval has been obtained from Oxford University's Tropical Research Ethics Committee (OxTREC), and as locally mandated at each site.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number: ISRCTN59144167 26-July-2012.

Meningitis in HIV-positive patients in sub-Saharan Africa: a review

INTRODUCTION

Meningitis is one of the leading causes of death among patients living with HIV in sub-Saharan Africa. There is no widespread tracking of the incidence rates of causative agents among patients living with HIV, yet the aetiologies of meningitis are different than those of the general population.

METHODS

We reviewed the scientific literature published in PubMed to determine the incidence rates of meningitis among hospitalized people living with HIV in sub-Saharan Africa and report our findings from seven studies across sub-Saharan Africa.

RESULTS

We found high rates of cryptococcal meningitis (19-68%). Tuberculous meningitis was lower (1-36%), although some centres included possible cases as "other" meningitis; therefore, this may not be a true representation of the total cases. Pyogenic meningitis ranged from 6 to 30% and "other" meningitis ranged from 7 to 28% of all reported cases of meningitis. Mortality rates ranged from 25 to 68%. This review describes the most common aetiologies and provides practical diagnostic, treatment and prevention considerations as they apply to the individual living with HIV in sub-Saharan Africa.

CONCLUSIONS

Diagnosis is often limited, and wider availability of accurate and low-cost laboratory diagnostics is desperately needed for prompt diagnosis and initiation of appropriate treatment. Wider acceptance and adoption of available preventative modalities can decrease the incidence of potentially fatal central nervous system infections in African patients living with HIV.

Outcome Assessments in Clinical Trials of Cryptococcal Meningitis: Considerations on Use of Early Fungicidal Activity as a Potential Surrogate Endpoint for All-Cause Mortality

Cryptococcal meningitis (CM) is a common disease in resource-challenged settings, with a high mortality within weeks of disease onset. Mortality remains high with current treatments, so more effective interventions are needed to decrease mortality. There has been interest in using the outcome assessment of quantification of fungus from cerebrospinal fluid as a replacement (surrogate) endpoint for all-cause mortality (ACM) as a means of decreasing sample size in randomized clinical trials in CM. To evaluate a biomarker as a potential surrogate endpoint to replace ACM requires several steps. This paper discusses the issues of determining whether the context of a disease is one where a potential surrogate endpoint is rational, the types of outcome assessments that might qualify as potential surrogates, and the process for evaluation of the evidence that a chosen biomarker is a valid replacement for ACM in the given context of use. We then apply those principles to the context of randomized clinical trials of CM.

Cryptococcal meningitis: epidemiology and therapeutic options

Cryptococcal meningitis causes morbidity and mortality worldwide. The burden of disease is greatest in middle- and low-income countries with a high incidence of human immunodeficiency virus (HIV) infection. Patients taking immunosuppressive drugs and some immunocompetent hosts are also at risk. Treatment of cryptococcal meningitis consists of three phases: induction, consolidation, and maintenance. Effective induction therapy requires potent fungicidal drugs (amphotericin B and flucytosine), which are often unavailable in low-resource, high-endemicity settings. As a consequence, mortality is unacceptably high. Wider access to effective treatment is urgently required to improve outcomes. For human immunodeficiency virus-infected patients, judicious management of asymptomatic cryptococcal antigenemia and appropriately timed introduction of antiretroviral therapy are important.

Overview of vertebrate animal models of fungal infection

Fungi represent emerging infectious threats to human populations worldwide. Mice and other laboratory animals have proved invaluable in modeling clinical syndromes associated with superficial and life-threatening invasive mycoses. This review outlines salient features of common vertebrate animal model systems to study fungal pathogenesis, host antifungal immune responses, and antifungal compounds.

Determinants of mortality in a combined cohort of 501 patients with HIV-associated Cryptococcal meningitis: implications for improving outcomes

Cerebrospinal fluid fungal burden, altered mental status, and rate of clearance of infection predict acute mortality in HIV-associated cryptococcal meningitis. The identification of factors associated with mortality informs strategies to improve outcomes.

Background. Cryptococcal meningitis (CM) is a leading cause of death in individuals infected with human immunodeficiency virus (HIV). Identifying factors associated with mortality informs strategies to improve outcomes.

Methods. Five hundred one patients with HIV-associated CM were followed prospectively for 10 weeks during trials in Thailand, Uganda, Malawi, and South Africa. South African patients (n = 266) were followed for 1 year. Similar inclusion/exclusion criteria were applied at all sites. Logistic regression identified baseline variables independently associated with mortality.

Results. Mortality was 17% at 2 weeks and 34% at 10 weeks. Altered mental status (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.7–5.9), high cerebrospinal fluid (CSF) fungal burden (OR, 1.4 per log₁₀ colony-forming units/mL increase; 95% CI, 1.0–1.8), older age (>50 years; OR, 3.9; 95% CI, 1.4–11.1), high peripheral white blood cell count (>10 × 10⁹ cells/L; OR, 8.7; 95% CI, 2.5–30.2), fluconazole-based induction treatment, and slow clearance of CSF infection were independently associated with 2-week mortality. Low body weight, anemia (hemoglobin <7.5 g/dL), and low CSF opening pressure were independently associated with mortality at 10 weeks in addition to altered mental status, high fungal burden, high peripheral white cell count, and older age.

In those followed for 1 year, overall mortality was 41%. Immune reconstitution inflammatory syndrome occurred in 13% of patients and was associated with 2-week CSF fungal burden (P = .007), but not with time to initiation of antiretroviral therapy (ART).

Conclusions. CSF fungal burden, altered mental status, and rate of clearance of infection predict acute mortality in HIV-associated CM. The results suggest that earlier diagnosis, more rapidly fungicidal amphotericin-based regimens, and prompt immune reconstitution with ART are priorities for improving outcomes.

Cryptococcus albidus encephalitis in newly diagnosed HIV-patient and literature review

We present the first case of encephalitis caused by Cryptococcus albidus duo to AIDS. In addition, we give an overview of the literature of extra-dermal infection cases caused by C. albidus. In the 21 cases, HIV and organ transplantation were important risk factors especially in recent 20 years. Fungal culture or India ink preparations are the best way to demonstrate C. albidus in both serum and CSF.