Impact of HIV infection on meningitis in Harare, Zimbabwe: a prospective study of 406 predominantly adult patients

Systematic review of tuberculous meningitis in high-risk populations: mortality and diagnostic disparities

Aim: Tuberculous meningitis (TBM) is one of the most severe clinical forms of tuberculosis (TB). Since epidemiological studies can contribute to TB control, we conducted a review and meta-analysis of epidemiological publications of adults TBM cases in countries with high incidence of TB.Materials & methods: The search resulted in 11,855 articles, in which 21 ultimately were included in our review and 15 in our meta-analysis.Results: TBM mortality was 25% with death rates of 70% in Africa. The review showed different and non-concordant diagnostic techniques and treatment schemes.Conclusion: Adults living in the African region are at high risk of death from TBM, highlighting an urgent need of guidelines to support diagnosis and treatment, and ultimately, to reduce mortality.

Management and outcome of intracranial fungal infections in children and adults in Africa: a scoping review

INTRODUCTION

Intracranial fungal infections' (IcFIs) varying clinical manifestations lead to difficulties in diagnosis and treatment. African populations are disproportionately affected by the high burden of the disease. There is a lack of clarity as to the diagnostic and treatment modalities employed across the continent. In this review, we aim to detail the management, and outcome of IcFIs across Africa.

METHODS

This scoping review was conducted using the Arksey and O'Malley framework. MEDLINE, EMBASE, Cochrane Library, African Index Medicus, and African Journals Online were searched for relevant articles from database inception to August 10th, 2021. The Preferred Reporting Items for Systematic Review and Meta-Analysis extension for Scoping Reviews guidelines were used to report the findings of the review.

RESULTS

Of the 5,779 records identified, 131 articles were included. The mean age was 35.6 years, and the majority (56.4%) were males. The majority (n = 8,433/8,693, 97.0%) of IcFIs presented as a meningitis, the most common communicable predisposing factor of IcFIs was HIV/AIDS (n = 7,815/8,693, 89.9%), and the most common non-communicable risk factor was diabetes mellitus (n = 32/8,693, 0.4%). Cryptococcus species was the most common (n = 8,428/8,693, 97.0%) causative organism. The most commonly used diagnostic modality was cerebrospinal (CSF) cultures (n = 4,390/6,830, 64.3%) for diffuse IcFIs, and MRI imaging (n = 12/30, 40%) for focal IcFIs. The most common treatment modality was medical management with antifungals only (n = 4,481/8,693, 51.6%). The most commonly used antifungal agent in paediatric, and adult patients was amphotericin B and fluconazole dual therapy (51.5% vs 44.9%). The overall mortality rate was high (n = 3,475/7,493, 46.3%), and similar for both adult and paediatric patients (47.8% vs 42.1%).

CONCLUSION

Most IcFIs occurred in immunosuppressed individuals, and despite the new diagnostic techniques, CSF culture was mostly used in Africa. Antifungals regimens used was similar between children and adults. The outcome of IcFIs in Africa was poor for both paediatric and adult patients.

Prevalence and Factors Associated With Cryptoccocal Antigenemia Among Patients With Advanced Human Immunodeficiency Virus in Eastern Uganda: A Facility-Based Cross-sectional Study

Background

Cryptoccocal infection remains an important cause of morbidity and mortality among people with advanced human immunodeficiency virus disease (AHD). In resource-limited settings, there is a paucity of data on cryptoccocal infections. We described the prevalence and factors associated with cryptoccocal antigenemia among people with AHD in Mbale Regional Referral Hospital in Eastern Uganda.

Methods

In this cross-sectional study, data on sociodemographic, clinical, and laboratory characteristics of adults with AHD were collected, and factors associated with cryptoccocal antigenemia were determined using multivariate logistic regression models.

Results

We enrolled 228 participants with a median CD4 cell count of 194/µL (interquartile range, 129-370/µL). The prevalence of cryptoccocal antigen was 10 in 228 (4.4% [95% confidence interval, 2.4%-80%]). CD4 cell counts <100/µL (adjusted odds ratio, 3.70) and poultry keeping were risk factors. The main predictors were headaches (adjusted odds ratio, 1), neck pains (8.817), confusion (6.323), and neck stiffness (676.217). No notable significant associations were found in the multivariate analysis.

Conclusions

The prevalence of cryptoccocal antigen was 4.4%, and antiretroviral therapy was protective.

Analyses of the Global Multilocus Genotypes of the Human Pathogenic Yeast Cryptococcus neoformans Species Complex

Cryptococcus neoformans species complex (CNSC) is a globally distributed human opportunistic yeast pathogen consisting of five major molecular types (VNI, VNII, VNB, VNIII and VNIV) belonging to two species, C. neoformans (VNI, VNII and VNB, collectively called serotype A) and C. deneoformans (VNIV, commonly called serotype D), and their hybrids (VNIII, serotype AD). Over the years, many studies have analyzed the geographical distribution and genetic diversity of CNSC. However, the global population structure and mode of reproduction remain incompletely described. In this study, we analyze the published multilocus sequence data at seven loci for CNSC. The combined sequences at the seven loci identified a total of 657 multilocus sequence types (STs), including 296 STs with known geographic information, representing 4200 non-redundant isolates from 31 countries and four continents. Among the 296 STs, 78 and 52 were shared among countries and continents, respectively, representing 3643 of the 4200 isolates. Except for the clone-corrected serotype D sample among countries, our analysis of the molecular variance of the 4200 isolates revealed significant genetic differentiations among countries and continents in populations of CNSC, serotype A, and serotype D. Phylogenetic analyses of the concatenated sequences of all 657 STs revealed several large clusters corresponding to the major molecular types. However, several rare but distinct STs were also found, representing potentially novel molecular types and/or hybrids of existing molecular types. Phylogenetic incompatibility analyses revealed evidence for recombination within all four major molecular types-VNI, VNII, VNIV and VNB-as well as within two VNB subclades, VNBI and VNBII, and two ST clusters around the most common STs, ST5 and ST93. However, linkage disequilibrium analyses rejected the hypothesis of random recombination across most samples. Together, our results suggest evidence for historical differentiation, frequent recent gene flow, clonal expansion and recombination within and between lineages of the global CNSC population.

Cryptococcus neoformans Genotypic Diversity and Disease Outcome among HIV Patients in Africa

Cryptococcal meningoencephalitis, a disease with poor patient outcomes, remains the most prevalent invasive fungal infection worldwide, accounting for approximately 180,000 deaths each year. In several areas of sub-Saharan Africa with the highest HIV prevalence, cryptococcal meningitis is the leading cause of community-acquired meningitis, with a high mortality among HIV-infected individuals. Recent studies show that patient disease outcomes are impacted by the genetics of the infecting isolate. Yet, there is still limited knowledge of how these genotypic variations contribute to clinical disease outcome. Further, it is unclear how the genetic heterogeneity of C. neoformans and the extensive phenotypic variation observed between and within isolates affects infection and disease. In this review, we discuss current knowledge of how various genotypes impact disease progression and patient outcome in HIV-positive populations in sub-Saharan African, a setting with a high burden of cryptococcosis.

Etiology of meningitis among adults in three quaternary hospitals in Mozambique, 2016-2017: The role of HIV

BACKGROUND

Meningitis remains an important cause of morbi-mortality in adults in sub-Saharan Africa. Data on the etiological investigation of meningitis in adults in Mozambique is limited and most studies were conducted in southern Mozambique. Identification of the etiology of meningitis in adults are crucial to guide prevention and treatments strategies. In this study, we determine the burden of fungal and bacterial meningitis among adults at the three largest hospitals in Mozambique.

METHOD

We performed analysis of data from the routine sentinel surveillance system for meningitis in Mozambique from January 2016 to December 2017. Cerebrospinal fluid (CSF) samples were collected from eligible adults (≥18 years old) who met World Health Organization (WHO) case definition criteria for Meningitis. All samples were tested by cryptococcal antigen (CrAg) lateral flow assay (LFA), culture and triplex real-time polymerase chain reaction (qPCR) assay and all patients were tested for human immunodeficiency virus (HIV) using the national algorithm for HIV testing.

RESULTS

Retrospective analysis of 1501 CSF samples from adults clinically suspected of meningitis revealed that 10.5% (158/1501) were positive for bacterial and fungal meningitis. Of these 158 confirmed cases, the proportion of Cryptococcal meningitis and pneumococcal meningitis was38.6% (95% CI: 31.0% to 46.7%) and 36.7% (95% CI: 29.2% to 44.7%), respectively. The other bacterial agents of meningitis identified include Neisseria meningitidis (8.9%; 14/158), Escherichia coli (6.3%; 10/158), Haemophilus influenzae (5.1%; 8/158) and S. aureus (4.4%; 7/158), which represent (24.7%; 39/158) of the total confirmed cases.

CONCLUSION

Altogether, our findings show a high burden of Cryptococcal meningitis among adults in Mozambique, especially in people living with HIV, followed by pneumococcal meningitis. Our findings suggest that rollout of CrAg Lateral Flow Assay in the health system in Mozambique for early detection of cryptococcus neoformans is necessary to improve overall patient care.

Global morbidity and mortality of central nervous system tuberculosis: a systematic review and meta-analysis

Background

Tuberculosis (TB) is the second most common cause of death due to a single infectious agent worldwide after COVID-19. Up to 15% of the cases are extrapulmonary, and if it is located in the central nervous system (CNS-TB), it presents high morbidity and mortality. Still, the global epidemiology of CNS-TB remains unknown.

Aim

To estimate the global prevalence and incidence of CNS-TB based on the available literature.

Methods

We systematically searched in MEDLINE, Cochrane Central, Scopus, and LILACS databases (April 2020) and included observational studies evaluating the epidemiology of CNS-TB. Two independent researchers selected and assessed the quality of the studies and extracted relevant data. We performed random-effects model meta-analysis of proportions to estimate the pooled prevalence. The protocol of this study was registered in PROSPERO (CRD 42018103946).

Results

We included 53 studies from 28 countries, representing 12,621 patients with CNS-TB. The prevalence of CNS-TB was 2 per 100,000 inhabitants. According to the clinical setting, the prevalence of CNS-TB represented the 13.91% of all cases of meningitis and 4.55% of all cases of TB. The mortality was calculated by tuberculous meningitis due to the lack of data of other presentation, and it rose up to 42.12% in hospitalized patients. The burden of countries’ TB, Human Development Index (HDI), and the prevalence of HIV were the most important prevalence moderators, especially in patients with TB. No data on incidence were found.

Conclusion

The prevalence and mortality of CNS-TB remain high, and TB meningitis is the most frequent presentation. The highest prevalence was reported in developing countries, and its main moderators were the countries’ HDI and HIV infection. Our study was limited by high heterogeneity, risk of bias, and potential data under registration from developing countries. The integration of CNS-TB early detection and management into national TB programs and population-based studies from developing countries are needed for better global estimation and response.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-11052-8.

Survival following screening and preemptive antifungal therapy for subclinical cryptococcal disease in advanced HIV infection

OBJECTIVES

Our study's primary objective was to compare 1-year survival rates between serum cryptococcal antigen (sCrAg)-positive and sCrAg-negative HIV-positive individuals with CD4+ cell counts less than 100 cells/μl without symptoms of meningitis in Zimbabwe.

DESIGN

This was a prospective cohort study.

METHODS

Participants were enrolled as either sCrAg-positive or sCrAg-negative and followed up for 52 weeks or less, with death as the outcome. Lumbar punctures were recommended to all sCrAg-positives and inpatient management with intravenous amphotericin B and high-dose fluconazole was recommended to those with disseminated Cryptococcus. Antiretroviral therapy was initiated immediately in sCrAg-negatives and after at least 4 weeks following initiation of antifungals in sCrAg-positives. Multivariable logistic regression models were used to determine risk factors for mortality.

RESULTS

We enrolled 1320 participants and 130 (9.8%) were sCrAg positive, with a median sCrAg titre of 1 : 20. Sixty-six (50.8%) sCrAg-positives had lumbar punctures and 16.7% (11/66) had central nervous system (CNS) dissemination. Cryptococcal blood cultures were performed in 129 sCrAg-positives, with 10 (7.8%) being positive. One-year (48-52 weeks) survival rates were 83.9 and 76.1% in sCrAg-negatives and sCrAg-positives, respectively, P = 0.011. Factors associated with increased mortality were a positive sCrAg, CD4+ cell count less than 50 cells/μl and having presumptive tuberculosis (TB) symptoms.

CONCLUSION

Our study reports a high prevalence of subclinical cryptococcal antigenemia and reiterates the importance of TB and a positive sCrAg as risk factors for mortality in advanced HIV disease (AHD). Therefore, TB and sCrAg screening remains a crucial component of AHD package, hence it should always be part of the comprehensive clinical evaluation in AHD patients.

Nitrogen concentration affects amphotericin B and fluconazole tolerance of pathogenic cryptococci

Environmental stress often causes phenotypic changes among pathogenic cryptococci, such as altered antifungal susceptibility, changes in capsule and melanin formation, as well as altered levels of the membrane sterol and antifungal target, ergosterol. We therefore hypothesised that nitrogen limitation, a prevalent environmental stress in the natural habitat of these yeasts, might affect virulence and antifungal susceptibility. We tested the effect of different nitrogen concentrations on capsule, melanin and ergosterol biosynthesis, as well as amphotericin B (AmB) and fluconazole (FLU) susceptibility. This was achieved by culturing cryptococcal strains representing Cryptococcus neoformans and Cryptococcus gattii in media with high (0.53 g/l), control (0.42 g/l) and low (0.21 g/l) NH4Cl concentrations. India ink staining was used to determine capsule thickness microscopically, while melanin and ergosterol content were determined spectrophotometrically. We found that lower nitrogen concentrations enhanced both ergosterol and capsule biosynthesis, while a variable effect was observed on melanisation. Evaluation of drug tolerance using time-kill methodology, as well as tests for FLU heteroresistance, revealed that the low nitrogen cultures had the highest survival percentages in the presence of both AmB and FLU, and showed the highest frequency of FLU heteroresistance, suggesting that nitrogen concentration may indeed influence drug tolerance.

Determining the burden of fungal infections in Zimbabwe

Zimbabwe currently faces several healthcare challenges, most notably HIV and associated infections including tuberculosis (TB), malaria and recently outbreaks of cholera, typhoid fever and COVID-19. Fungal infections, which are also a major public health threat, receive considerably less attention. Consequently, there is dearth of data regarding the burden of fungal diseases in the country. We estimated the burden of fungal diseases in Zimbabwe based on published literature and 'at-risk' populations (HIV/AIDS patients, survivors of pulmonary TB, cancer, chronic obstructive pulmonary disease, asthma and patients receiving critical care) using previously described methods. Where there was no data for Zimbabwe, regional, or international data was used. Our study revealed that approximately 14.9% of Zimbabweans suffer from fungal infections annually, with 80% having tinea capitis. The annual incidence of cryptococcal meningitis and Pneumocystis jirovecii pneumonia in HIV/AIDS were estimated at 41/100,000 and 63/100,000, respectively. The estimated prevalence of recurrent vulvovaginal candidiasis (RVVC) was 2,739/100,000. The estimated burden of fungal diseases in Zimbabwe is high in comparison to other African countries, highlighting the urgent need for increased awareness and surveillance to improve diagnosis and management.

Review of the neurological aspects of HIV infection

There are almost 40 million people in the world who live with the human immunodeficiency virus (HIV). The neurological manifestations associated with HIV contribute to significant morbidity and mortality despite the advances made with anti-retroviral therapy (ART). This review presents an approach to classification of neurological disorders in HIV, differentiating diseases due to the virus itself and those due to opportunistic infection. The effects of antiretroviral therapy are also discussed. The emphasis is on the developing world where advanced complications of HIV itself and infections such as tuberculosis (TB), toxoplasmosis and cryptococcal meningitis remain prevalent.

High-Dose Oral and Intravenous Rifampicin for the Treatment of Tuberculous Meningitis in Predominantly Human Immunodeficiency Virus (HIV)-Positive Ugandan Adults: A Phase II Open-Label Randomized Controlled Trial

BACKGROUND

High-dose rifampicin may improve outcomes of tuberculous meningitis (TBM). Little safety or pharmacokinetic (PK) data exist on high-dose rifampicin in human immunodeficiency virus (HIV) coinfection, and no cerebrospinal fluid (CSF) PK data exist from Africa. We hypothesized that high-dose rifampicin would increase serum and CSF concentrations without excess toxicity.

METHODS

In this phase II open-label trial, Ugandan adults with suspected TBM were randomized to standard-of-care control (PO-10, rifampicin 10 mg/kg/day), intravenous rifampicin (IV-20, 20 mg/kg/day), or high-dose oral rifampicin (PO-35, 35 mg/kg/day). We performed PK sampling on days 2 and 14. The primary outcomes were total exposure (AUC0-24), maximum concentration (Cmax), CSF concentration, and grade 3-5 adverse events.

RESULTS

We enrolled 61 adults, 92% were living with HIV, median CD4 count was 50 cells/µL (interquartile range [IQR] 46-56). On day 2, geometric mean plasma AUC0-24hr was 42.9·h mg/L with standard-of-care 10 mg/kg dosing, 249·h mg/L for IV-20 and 327·h mg/L for PO-35 (P < .001). In CSF, standard of care achieved undetectable rifampicin concentration in 56% of participants and geometric mean AUC0-24hr 0.27 mg/L, compared with 1.74 mg/L (95% confidence interval [CI] 1.2-2.5) for IV-20 and 2.17 mg/L (1.6-2.9) for PO-35 regimens (P < .001). Achieving CSF concentrations above rifampicin minimal inhibitory concentration (MIC) occurred in 11% (2/18) of standard-of-care, 93% (14/15) of IV-20, and 95% (18/19) of PO-35 participants. Higher serum and CSF levels were sustained at day 14. Adverse events did not differ by dose (P = .34).

CONCLUSIONS

Current international guidelines result in sub-therapeutic CSF rifampicin concentration for 89% of Ugandan TBM patients. High-dose intravenous and oral rifampicin were safe and respectively resulted in exposures ~6- and ~8-fold higher than standard of care, and CSF levels above the MIC.

Standardized Urine-Based Tuberculosis (TB) Screening With TB-Lipoarabinomannan and Xpert MTB/RIF Ultra in Ugandan Adults With Advanced Human Immunodeficiency Virus Disease and Suspected Meningitis

BACKGROUND

Diagnosis of extrapulmonary tuberculosis (TB) remains challenging. We sought to determine the prevalence of disseminated TB by testing urine with TB-lipoarabinomannan (TB-LAM) lateral flow assay and Xpert MTB/RIF Ultra (Ultra) in hospitalized adults.

METHODS

We prospectively enrolled human immunodeficiency virus (HIV)-positive adults with suspected meningitis in Uganda during 2018-2020. Participants underwent standardized urine-based TB screening. Urine (60 mcL) was tested with TB-LAM (Alere), and remaining urine was centrifuged with the cell pellet resuspended in 2 mL of urine for Xpert Ultra testing.

RESULTS

We enrolled 348 HIV-positive inpatients with median CD4 of 37 cells/mcL (interquartile range, 13-102 cells/mcL). Overall, 26% (90 of 348; 95% confidence interval [CI], 21%-30%) had evidence of disseminated TB by either urine assay. Of 243 participants with both urine TB-LAM and Ultra results, 20% (48 of 243) were TB-LAM-positive, 12% (29 of 243) were Ultra-positive, and 6% (14 of 243) were positive by both assays. In definite and probable TB meningitis, 37% (14 of 38) were TB-LAM-positive and 41% (15 of 37) were Ultra-positive. In cryptococcal meningitis, 22% (40 of 183) were TB-LAM-positive and 4.4% (6 of 135) were Ultra-positive. Mortality trended higher in those with evidence of disseminated TB by either assay (odds ratio = 1.44; 95% CI, 0.83-2.49; P = .19) and was 6-fold higher in those with definite TB meningitis who were urine Ultra-positive (odds ratio = 5.67; 95% CI, 1.13-28.5; P = .04).

CONCLUSIONS

In hospitalized Ugandans with advanced HIV disease and suspected meningitis, systematic screening with urine TB-LAM and Ultra found a high prevalence of urine TB test positivity (26%). In those with TB meningitis, urine tests were positive in over one third. There was little concordance between Ultra and TB-LAM, which warrants further investigation.

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.

The Changing Epidemiology of HIV-Associated Adult Meningitis, Uganda 2015-2017

Background

Central nervous system (CNS) infections remain a major public health problem in Sub-Saharan Africa, causing 15%–25% of AIDS-related deaths. With widespread availability of antiretroviral therapy (ART) and the introduction of improved diagnostics, the epidemiology of infectious meningitis is evolving.

Methods

We prospectively enrolled adults presenting with HIV-associated meningitis in Kampala and Mbarara, Uganda, from March 2015 to September 2017. Participants had a structured, stepwise diagnostic algorithm performed of blood cryptococcal antigen (CrAg), CSF CrAg, Xpert MTB/RIF for tuberculous (TB) meningitis (TBM), Biofire multiplex polymerase chain reaction, and traditional microscopy and cultures.

Results

We screened 842 consecutive adults with HIV presenting with suspected meningitis: 57% men, median age 35 years, median CD4 26 cells/mcL, and 55% presented on ART. Overall, 60.5% (509/842) were diagnosed with first-episode cryptococcal meningitis and 7.4% (62/842) with second episode. Definite/probable TB meningitis was the primary diagnosis in 6.9% (58/842); 5.3% (n = 45) had microbiologically confirmed (definite) TB meningitis. An additional 7.8% (66/842) did not meet the diagnostic threshold for definite/probable TBM but received empiric TBM therapy. Bacterial and viral meningitis were diagnosed in 1.3% (11/842) and 0.7% (6/842), respectively. The adoption of a cost-effective stepwise diagnostic algorithm allowed 79% (661/842) to have a confirmed microbiological diagnosis at an average cost of $44 per person.

Conclusions

Despite widespread ART availability, Cryptococcus remains the leading cause of HIV-associated meningitis. The second most common etiology was TB meningitis, treated in 14.7% overall. The increased proportion of microbiologically confirmed TBM cases reflects the impact of new improved molecular diagnostics.

Mortality in adult patients with culture-positive and culture-negative meningitis in the Botswana national meningitis survey: a prevalent cohort study

BACKGROUND

CNS infections are a leading cause of HIV-related deaths in sub-Saharan Africa, but causes and outcomes are poorly defined. We aimed to determine mortality and predictors of mortality in adults evaluated for meningitis in Botswana, which has an estimated 23% HIV prevalence among adults.

METHODS

In this prevalent cohort study, patient records from 2004-15 were sampled from the Botswana national meningitis survey, a nationwide audit of all cerebrospinal fluid (CSF) laboratory records from patients receiving a lumbar puncture for evaluation of meningitis. Data from all patients with culture-confirmed pneumococcal and tuberculous meningitis, and all patients with culture-negative meningitis with CSF white cell count (WCC) above 20 cells per μL were included in our analyses, in addition to a random selection of patients with culture-negative CSF and CSF WCC of up to 20 cells per μL. We used patient national identification numbers to link CSF laboratory records from the national meningitis survey to patient vital registry and HIV databases. Univariable and multivariable Cox proportional hazards models were used to evaluate clinical and laboratory predictors of mortality.

FINDINGS

We included data from 238 patients with culture-confirmed pneumococcal meningitis, 48 with culture-confirmed tuberculous meningitis, and 2900 with culture-negative CSF (including 1691 with CSF WCC of up to 20 cells per μL and 1209 with CSF WCC above 20 cells per μL). Median age was 37 years (IQR 31-46), 1605 (50%) of 3184 patients were male, 2188 (72%) of 3023 patients with registry linkage had documentation of HIV infection, and median CD4 count was 139 cells per μL (IQR 63-271). 10-week and 1-year mortality was 47% (112 of 238) and 49% (117 of 238) for pneumococcal meningitis, 46% (22 of 48) and 56% (27 of 48) for tuberculous meningitis, and 41% (1181 of 2900) and 49% (1408 of 2900) for culture-negative patients. When the analysis of patients with culture-negative CSF was restricted to those with known HIV infection, WCC (0-20 cells per μL vs >20 cells per μL) was not predictive of mortality (average hazard ratio 0·93, 95% CI 0·80-1·09).

INTERPRETATION

Mortality from pneumococcal, tuberculous, and culture-negative meningitis was high in this setting of high HIV prevalence. There is an urgent need for improved access to diagnostics, to better define aetiologies and develop novel diagnostic tools and treatment algorithms.

FUNDING

National Institutes of Health, President's Emergency Plan for AIDS Relief, National Institute for Health Research.

HIV-Associated Cryptococcal Immune Reconstitution Inflammatory Syndrome Is Associated with Aberrant T Cell Function and Increased Cytokine Responses

Cryptococcal meningitis remains a significant opportunistic infection among HIV-infected patients, contributing 15-20% of HIV-related mortality. A complication of initiating antiretroviral therapy (ART) following opportunistic infection is immune reconstitution inflammatory syndrome (IRIS). IRIS afflicts 10-30% of HIV-infected patients with cryptococcal meningitis (CM), but its immunopathogenesis is poorly understood. We compared circulating T cell memory subsets and cytokine responses among 17 HIV-infected Ugandans with CM: 11 with and 6 without CM-IRIS. At meningitis diagnosis, stimulation with cryptococcal capsule component, glucuronoxylomannan (GXM) elicited consistently lower frequencies of CD4⁺ and CD8⁺ T cell memory subsets expressing intracellular cytokines (IL-2, IFN-γ, and IL-17) among subjects who subsequently developed CM-IRIS. After ART initiation, T cells evolved to show a decreased CD8⁺ central memory phenotype. At the onset of CM-IRIS, stimulation more frequently generated polyfunctional IL-2⁺/IL-17⁺ CD4⁺ T cells in patients with CM-IRIS. Moreover, CD8⁺ central and effector memory T cells from CM-IRIS subjects also demonstrated more robust IL-2 responses to antigenic stimulation vs. controls. Thus, ART during CM elicits distinct differences in T cell cytokine production in response to cryptococcal antigens both prior to and during the development of IRIS, suggesting an immunologic foundation for the development of this morbid complication of CM infection.

Estimated Burden of Serious Fungal Infections in Mozambique

Mozambique is a sub-Saharan African country with limited information on the burden of fungal disease. We estimate the burden of serious fungal infections for the general healthy population and for those at risk, including those infected with HIV, patients with asthma, as well as those under intensive care. We consult the Mozambican National Institute of Statistics Population and Housing Census report to obtain denominators for different age groups. We use modelling and HIV data to estimate the burdens of Pneumocystis jirovecii pneumonia (PCP), Cryptococcal meningitis (CM) and candidiasis. Asthma, chronic obstructive pulmonary disease and tuberculosis data were used to estimate the burden of allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis (CPA). In 2016, the Mozambique population was 26.4 million with 1.8 million people reported to be HIV-infected. Estimated annual incidence of fungal infections was: 33,380 PCP, 18,640 CM and 260,025 oral and oesophageal candidiasis cases. Following pulmonary tuberculosis, estimated numbers of people having chronic pulmonary aspergillosis (prevalence) and allergic bronchopulmonary aspergillosis complicating asthma are 18,475 and 15,626, respectively. Tinea capitis is common in children with over 1.1 million probably affected. We also highlight from studies in progress of high incidences of Histoplasmosis, CM and Pneumocystis jirovecii in adult HIV-infected patients. Prospective epidemiology studies with sensitive diagnostics are required to validate these estimates.

Community-Acquired Meningitis in HIV-Infected Patients in the United States

We conducted a retrospective study of 549 adults admitted with community-acquired meningitis (CAM) to several hospitals in New Orleans, LA and Houston, TX between 1999 and 2014 to characterize the current epidemiology, clinical manifestations, cerebrospinal fluid (CSF) characteristics, and outcomes of CAM between HIV-infected and uninfected patients and to identify risk factors for adverse outcomes in CAM. Bivariate analysis and logistic regression analysis were used to identify prognostic factors. A total of 1022 patients with CAM were screened. Only 549 (53.7%) subjects had an HIV test and were included in the study. Of those, 138 (25%) had HIV infection. HIV-infected patients presented with less meningeal symptoms (headache, neck stiffness, and Kernig sign), but with higher rates of hypoglycorrhachia, elevated CSF protein, and an abnormal cranial imaging (p < 0.05). More than 50% of all the patients had an unknown etiology. Cryptococcal meningitis was the most common identified etiology of CAM in HIV-infected patients followed by neurosyphilis and varicella-zoster virus (VZV). Viral and bacterial etiologies were the most frequent etiologies in non-HIV-infected patients. Streptococcus pneumoniae was the most common bacterial pathogen in both groups, but it was rare overall (2%). Adverse clinical outcomes were similar in both groups (27% vs. 24%). Logistic regression identified hypoglycorrhachia and an abnormal neurological examination as independent predictor factors of worse outcome in all patients with meningitis. Our results demonstrate that the etiology, clinical presentation, and CSF findings differ between HIV-infected and HIV-uninfected adults with CAM, but clinical outcomes are similar.

Clinical features vary by the aetiology of meningitis in HIV seropositive patients: A four-year study from a tertiary hospital in India

Meningitis is a serious infection of the nervous system associated with high mortality in Human Immunodeficiency Virus (HIV) seropositive individuals. Asian clinical studies describing meningitis in people living with HIV are scarce. We describe the clinical features of meningitis in 116 HIV seropositive patients from a tertiary hospital in India as a cross-sectional observational study. The mean age of the patients in our study was 35±9 years with 70.6% of them being men. Eighty-five percent of the patients had an altered sensorium during the illness. Tuberculous meningitis [82.6%] was the most common cause. Clinical features varied by aetiology. Cranial nerve deficits [40%] were common in Cryptococcal meningitis. Hydrocephalus [3%], infarcts [15.9%] and IntraCranial Space Occupying Lesions (ICSOLs) [39.1%] were common in tuberculous meningitis.

Monocyte Phenotype and IFN-γ-Inducible Cytokine Responses Are Associated with Cryptococcal Immune Reconstitution Inflammatory Syndrome

A third of adults with AIDS and cryptococcal meningitis (CM) develop immune reconstitution inflammatory syndrome (IRIS) after initiating antiretroviral therapy (ART), which is thought to result from exaggerated inflammatory antigen-specific T cell responses. The contribution of monocytes to the immunopathogenesis of cryptococcal IRIS remains unclear. We compared monocyte subset frequencies and immune responses in HIV-infected Ugandans at time of CM diagnosis (IRIS-Baseline) for those who later developed CM-IRIS, controls who did not develop CM-IRIS (Control-Baseline) at CM-IRIS (IRIS-Event), and for controls at a time point matched for ART duration (Control-Event) to understand the association of monocyte distribution and immune responses with cryptococcal IRIS. At baseline, stimulation with IFN-γ ex vivo induced a higher frequency of TNF-α- and IL-6-producing monocytes among those who later developed IRIS. Among participants who developed IRIS, ex vivo IFN-γ stimulation induced higher frequencies of activated monocytes, IL-6⁺, TNF-α⁺ classical, and IL-6⁺ intermediate monocytes compared with controls. In conclusion, we have demonstrated that monocyte subset phenotype and cytokine responses prior to ART are associated with and may be predictive of CM-IRIS. Larger studies to further delineate innate immunological responses and the efficacy of immunomodulatory therapies during cryptococcal IRIS are warranted.

Brief Report: Geographical Variation in Prevalence of Cryptococcal Antigenemia Among HIV-Infected, Treatment-Naive Patients in Nigeria: A Multicenter Cross-Sectional Study

OBJECTIVE

Worldwide, HIV-associated cryptococcal meningitis affects approximately 1 million persons and causes 600,000 deaths each year mostly in sub-Saharan Africa. Limited data exist on cryptococcal meningitis and antigenemia in Nigeria, and most studies are geographically restricted. We determined the prevalence of cryptococcal antigenemia (CrAg) among HIV-infected, treatment-naive individuals in Nigeria.

DESIGN/METHODS

This was a retrospective, cross-sectional study across 4 geographic regions in Nigeria. We performed CrAg testing using a lateral flow immunoassay on archived whole-blood samples collected from HIV-infected participants at US President's Emergency Plan for AIDS Relief (PEPFAR)-supported sites selected to represent the major geographical and ethnic diversity in Nigeria. Eligible samples were collected from consenting patients (>15 years) naive to antiretroviral therapy with CD4 count less than 200 cells per cubic millimeter and were stored in an -80°C freezer.

RESULTS

A total of 2752 stored blood samples were retrospectively screened for CrAg. Most of the samples were from participants aged 30-44 years (57.6%), and 1570 (57.1%) were from women. The prevalence of CrAg positivity in specimens with CD4 <200 cells per cubic millimeter was 2.3% (95% confidence interval: 1.8% to 3.0%) and varied significantly across the 4 regions (P < 0.001). At 4.4% (3.2% to 5.9%), the South East contained the highest prevalence.

CONCLUSIONS

The significant regional variation in CrAg prevalence found in Nigeria should be taken into consideration as plans are made to integrate routine screening into clinical care for HIV-infected patients.

Is it possible to differentiate tuberculous and cryptococcal meningitis in HIV-infected patients using only clinical and basic cerebrospinal fluid characteristics?

BACKGROUND

Tuberculous and cryptococcal meningitis (TBM and CM) are the most common causes of opportunistic meningitis in HIVinfected patients from resource-limited settings, and the differential diagnosis is challenging.

OBJECTIVE

To compare clinical and basic cerebrospinal fluid (CSF) characteristics between TBM and CM in HIV-infected patients.

METHODS

A retrospective analysis was conducted of clinical, radiological and laboratory records of 108 and 98 HIV-infected patients with culture-proven diagnosis of TBM and CM, respectively. The patients were admitted at a tertiary centre in São Paulo, Brazil. A logistic regression model was used to distinguish TBM from CM and derive a diagnostic index based on the adjusted odds ratio (OR) to differentiate these two diseases.

RESULTS

In multivariate analysis, TBM was independently associated with: CSF with neutrophil predominance (odds ratio (OR) 35.81, 95% confidence interval (CI) 3.80 - 341.30, p=0.002), CSF pleocytosis (OR 9.43, 95% CI 1.30 - 68.70, p=0.027), CSF protein &gt;1.0 g/L (OR 5.13, 95% CI 1.38 - 19.04, p=0.032) and Glasgow Coma Scale &lt;15 (OR 3.10, 95% CI 1.03 - 9.34, p=0.044). Nausea and vomiting (OR 0.27, 95% CI 0.08 - 0.90, p=0.033) were associated with CM. Algorithm-related area under the receiver operating characteristics curve was 0.815 (95% CI 0.758 - 0.873, p&lt;0.0001), but an accurate cut-off was not derived.

CONCLUSION

Although some clinical and basic CSF characteristics appear useful in the differential diagnosis of TBM and CM in HIVinfected patients, an accurate algorithm was not identified. Optimised access to rapid, sensitive and specific laboratory tests is essential.

MLST-Based Population Genetic Analysis in a Global Context Reveals Clonality amongst Cryptococcus neoformans var. grubii VNI Isolates from HIV Patients in Southeastern Brazil

Cryptococcosis is an important fungal infection in immunocompromised individuals, especially those infected with HIV. In Brazil, despite the free availability of antiretroviral therapy (ART) in the public health system, the mortality rate due to Cryptococcus neoformans meningitis is still high. To obtain a more detailed picture of the population genetic structure of this species in southeast Brazil, we studied 108 clinical isolates from 101 patients and 35 environmental isolates. Among the patients, 59% had a fatal outcome mainly in HIV-positive male patients. All the isolates were found to be C. neoformans var. grubii major molecular type VNI and mating type locus alpha. Twelve were identified as diploid by flow cytometry, being homozygous (AαAα) for the mating type and by PCR screening of the STE20, GPA1, and PAK1 genes. Using the ISHAM consensus multilocus sequence typing (MLST) scheme, 13 sequence types (ST) were identified, with one being newly described. ST93 was identified from 81 (75%) of the clinical isolates, while ST77 and ST93 were identified from 19 (54%) and 10 (29%) environmental isolates, respectively. The southeastern Brazilian isolates had an overwhelming clonal population structure. When compared with populations from different continents based on data extracted from the ISHAM-MLST database (mlst.mycologylab.org) they showed less genetic variability. Two main clusters within C. neoformans var. grubii VNI were identified that diverged from VNB around 0.58 to 4.8 million years ago.

The members of the Cryptococcus neoformans / Cryptococcus gattii species complex are the cause of cryptococcosis, a life-threatening human disease responsible for 624,000 deaths annually. Infection is acquired through inhalation of dehydrated yeast cells from environmental sources. After reaching the lungs, the fungus disseminates to the central nervous system causing meningoencephalitis. The majority of meningitis cases in HIV-infected patients are caused by C. neoformans, a species well studied in regions with a high prevalence of HIV infection, such as Asia and Africa. A similar high prevalence has been reported from Brazil however the epidemiology of these infections is less well understood. We studied clinical and environmental isolates from the southeast region of Brazil using MLST. The results that we obtained showed a clonal population structure of C. neoformans var. grubii VNI, with low variability when compared against populations from different continents. This lower variability is probably the result of multiple recent dispersal events from Africa to the Americas. The majority of clinical isolates were of one sequence type (ST93), which was also found in environmental samples. By expanding the analysis to isolates from around the globe, it was possible to identify two major groups among C. neoformans var. grubii VNI.

The Epidemiology of Meningitis among Adults in a South African Province with a High HIV Prevalence, 2009-2012

INTRODUCTION

Meningitis is a major cause of mortality in southern Africa. We aimed to describe the aetiologies and frequencies of laboratory-confirmed fungal and bacterial meningitis among adults in a South African province with an 11% HIV prevalence, over 4 years.

METHODS

We conducted a retrospective, observational study of secondary laboratory data, extracted on all cerebrospinal fluid (CSF) specimens submitted to public-sector laboratories in Gauteng province from 2009 through 2012. We calculated cause-specific incidence rates in the general and HIV-infected populations and used Poisson regression to determine if trends were significant.

RESULTS

We identified 11,891 (10.7%) incident cases of meningitis from 110,885 CSF specimens. Cryptococcal meningitis, tuberculous meningitis and pneumococcal meningitis accounted for 62.3% (n = 7,406), 24.6% (n = 2,928) and 10.1% (n = 1,197) of cases over the four-year period. The overall incidence (cases per 100,000 persons) of cryptococcal meningitis declined by 23% from 24.4 in 2009 to 18.7 in 2012 (p <0.001) and decreased by 19% among HIV-infected persons from 178.2 to 144.7 (p <0.001). Tuberculous meningitis decreased by 40% from 11.3 in 2009 to 6.8 in 2012 (p <0.001) and decreased by 36% among HIV-infected persons from 54.4 to 34.9 (p <0.001). Pneumococcal meningitis decreased by 41% from 4.2 in 2009 to 2.5 in 2012 (p <0.001) and decreased by 38% among HIV-infected persons from 28.0 to 17.5 (p <0.001). Among cases of other bacterial meningitis (248/11,891, 2.1%), Neisseria meningitidis (n = 93), Escherichia coli (n = 72) and Haemophilus influenzae (n = 20) were the most common organisms identified.

CONCLUSIONS

In this high HIV-prevalence province, cryptococcal meningitis was the leading cause of laboratory-confirmed meningitis among adults. Over a 4-year period, there was a significant decrease in incidence of cryptococcal, tuberculous and pneumococcal meningitis. This coincided with expansion of the national antiretroviral treatment programme, enhanced tuberculosis control programme and routine childhood immunisation with pneumococcal conjugate vaccines.

Cysteinyl leukotrienes as novel host factors facilitating Cryptococcus neoformans penetration into the brain

Cryptococcus neoformas infection of the central nervous system (CNS) continues to be an important cause of mortality and morbidity, and a major contributing factor is our incomplete knowledge of the pathogenesis of this disease. Here, we provide the first direct evidence that C. neoformans exploits host cysteinyl leukotrienes (LTs), formed via LT biosynthetic pathways involving cytosolic phospholipase A₂ α (cPLA₂ α) and 5-lipoxygenase (5-LO) and acting via cysteinyl leukotriene type 1 receptor (CysLT1), for penetration of the blood-brain barrier. Gene deletion of cPLA₂ α and 5-LO and pharmacological inhibition of cPLA₂ α, 5-LO and CysLT1 were effective in preventing C. neoformans penetration of the blood-brain barrier in vitro and in vivo. A CysLT1 antagonist enhanced the efficacy of an anti-fungal agent in therapy of C. neoformans CNS infection in mice. These findings demonstrate that host cysteinyl LTs, dependent on the actions of cPLA₂ α and 5-LO, promote C. neoformans penetration of the blood-brain barrier and represent novel targets for elucidating the pathogenesis and therapeutic development of C. neoformans CNS infection.

Cryptococcus neoformans population diversity and clinical outcomes of HIV-associated cryptococcal meningitis patients in Zimbabwe

HIV and cryptococcal meningitis co-infection is a major public health problem in most developing countries. Cryptococcus neoformans sensu stricto is responsible for the majority of HIV-associated cryptococcosis cases in sub-Saharan Africa. Despite the available information, little is known about cryptococcal population diversity and its association with clinical outcomes in patients with HIV-associated cryptococcal meningitis in sub-Saharan Africa. In a prospective cohort, we investigated the prevalence and clinical outcome of Cryptococcusneoformans sensu stricto meningitis among HIV-infected patients in Harare, Zimbabwe, and compared the genotypic diversity of the isolates with those collected from other parts of Africa. Molecular typing was done using amplified fragment length polymorphism genotyping and microsatellite typing. The majority of patients with HIV-associated Cryptococcusneoformans sensu stricto meningitis in this cohort were males (n=33/55; 60.0 %). The predominant Cryptococcus neoformans sensu stricto genotype among the Zimbabwean isolates was genotype AFLP1/VNI (n=40; 72.7 %), followed by AFLP1A/VNB/VNII (n=8; 14.6 %), and AFLP1B/VNII was the least isolated (n=7; 12.7 %). Most of the isolates were mating-type α (n=51; 92.7 %), and only four (7.3 %) were mating-type a. Overall in-hospital mortality was 55.6 % (n=30), and no difference between infecting genotype and clinical outcome of patient (P=0.73) or CD4+ counts (P=0.79) was observed. Zimbabwean Cryptococcusneoformans sensu stricto genotypes demonstrated a high level of genetic diversity by microsatellite typing, and 51 genotypes within the main molecular types AFLP1/VNI, AFLP1A/VNB/VNII and AFLP1B/VNII were identified. This study demonstrates that Cryptococcusneoformans sensu stricto in Zimbabwe has a high level of genetic diversity when compared to other regional isolates.

Pattern, Clinical Characteristics, and Outcome of Meningitis among HIV-Infected Adults Admitted in a Tertiary Hospital in North Western Tanzania: A Cross-Sectional Study

Background. Limited information exists on the etiologies, clinical characteristics, and outcomes of meningitis among HIV-infected patients in Africa. We conducted a study to determine the etiology, clinical characteristics, and outcomes of meningitis among HIV-infected adults. Methods. A prospective cross-sectional hospital based study was conducted among HIV-infected patients aged ≥18 years admitted to the medical wards with symptoms and signs of meningitis. Sociodemographic and clinical information were collected using a standardized data collection tool. Lumbar puncture was performed to all patients; cerebrospinal fluid samples were sent for analysis. Results. Among 60 HIV-infected adults clinically diagnosed to have meningitis, 55 had CSF profiles consistent with meningitis. Of these, 14 (25.5%) had a laboratory-confirmed etiology while 41 (74.5%) had no isolate identified. Cryptococcus neoformans was the commonest cause of meningitis occurring in 11 (18.3%) of patients followed by Mycobacterium tuberculosis (6.7%). The in-hospital mortality was 20/55 (36.4%). Independent predictors of mortality were low baseline CD4 count and turbid CSF appearance. Conclusion. Cryptococcal meningitis is the most prevalent laboratory-confirmed etiological agent among adult HIV-infected patients with suspected meningitis admitted to medical wards in Western Tanzania. Mortality rate in this population remains unacceptably high. Improving diagnostic capacity and early treatment may help to decrease the mortality rate.

Differential diagnosis of stroke in a setting of high HIV prevalence in Blantyre, Malawi

BACKGROUND AND PURPOSE

The differential diagnosis of stroke in Africa in areas with high HIV prevalence includes brain infections. We studied causes of stroke in Blantyre, Malawi, where HIV prevalence among medical in-patients is 70%.

METHODS

In a descriptive study of 8 month duration, all patients presenting at Queen Elizabeth Central Hospital, Blantyre with central neurological deficit of acute onset (< 24 hours) had baseline investigations, including full blood count, blood glucose; serology for toxoplasmosis, syphilis and HIV; ECG, echocardiogram, ultrasound of the carotid arteries and computerized tomography scan of the brain. A lumbar puncture was performed unless contraindicated.

RESULTS

Ninety-eight consecutive patients (49 males) were studied. In those who were HIV positive (48%) the mean age was 37.5 years; ischemic stroke was the commonest diagnosis (n = 25, 58%) followed by infection (n=11, 23%; including tuberculous [n=4] and cryptococcal [n=2] meningitis; toxoplasmic encephalitis [n=1]; neurocysticercosis [n=1]; brain abscess [n=1]; and progressive multifocal leucoencephalopathy [n=2]). No clinical or laboratory parameters could be identified as predictors for infection, but 3 of 5 patients with fever on admission had tuberculous meningitis. In HIV negative patients (mean age 58.6 years) 55% had ischemic stroke and 31% had intracerebral hemorrhage; no brain infection was diagnosed. Presence of vascular disease correlated with age but not with HIV status.

CONCLUSIONS

Ischemic stroke was found in half of patients irrespective of HIV status. In those who are HIV positive, brain infection should be considered for which the presence of fever and examination of CSF seem most useful in diagnosis.

Burden of serious fungal infections in Tanzania

The incidence and prevalence of fungal infections in Tanzania remains unknown. We assessed the annual burden in the general population and among populations at risk. Data were extracted from 2012 reports of the Tanzanian AIDS program, WHO, reports, Tanzanian census, and from a comprehensive PubMed search. We used modelling and HIV data to estimate the burdens of Pneumocystis jirovecii pneumonia (PCP), cryptococcal meningitis (CM) and candidiasis. Asthma, chronic obstructive pulmonary disease and tuberculosis data were used to estimate the burden of allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis (CPA). Burdens of candidaemia and Candida peritonitis were derived from critical care and/or cancer patients' data. In 2012, Tanzania's population was 43.6 million (mainland) with 1,500,000 people reported to be HIV-infected. Estimated burden of fungal infections was: 4412 CM, 9600 PCP, 81,051 and 88,509 oral and oesophageal candidiasis cases respectively. There were 10,437 estimated post-tuberculosis CPA cases, whereas candidaemia and Candida peritonitis cases were 2181 and 327 respectively. No reliable data exist on blastomycosis, mucormycosis or fungal keratitis. Over 3% of Tanzanians suffer from serious fungal infections annually, mostly related to HIV. Cryptococcosis and PCP are major causes of mycoses-related deaths. National surveillance of fungal infections is urgently needed.

Bacterial Meningitis in a High HIV Prevalence Setting in Sub-Saharan Africa –Challenges to a Better Outcome

Bacterial meningitis remains an important cause of mortality and morbidity worldwide. Approaches to reducing the incidence include the deployment of effective anti-retroviral therapy in areas where HIV co-infection is common, vaccination, and prophylactic antibiotic therapy. Health education, improved diagnostic speed and capacity, and ensuring appropriate antibiotic therapy may improve outcome amongst patients presenting with bacterial meningitis.

A Patient Presenting with Tuberculous Encephalopathy and Human Immunodeficiency Virus Infection

BACKGROUND

In the USA, Mycobacterium tuberculosis infection is more likely to be found in foreign-born individuals, and those co-infected with human immunodeficiency virus (HIV) are more likely to have tuberculous meningitis. The literature is lacking in details about the clinical workup of patients presenting with tuberculous meningitis with encephalopathic features who are co-infected with HIV. This report demonstrates a clinical approach to diagnosis and management of tuberculous meningitis.

CASE REPORT

A 33-year-old Ecuadorean man presented with altered consciousness and constitutional symptoms. During the workup he was found to have tuberculous meningitis with encephalopathic features and concurrent HIV infection. Early evidence for tuberculosis meningitis included lymphocytic pleocytosis and a positive interferon gamma release assay. A confirmatory diagnosis of systemic infection was made based on lymph node biopsy. Imaging studies of the neck showed scrofula and adenopathy, and brain imaging showed infarctions, exudates, and communicating hydrocephalus. Treatment was started for tuberculous meningitis, while anti-retroviral therapy for HIV was started 5 days later in combination with prednisone, given the risk of immune reconstitution inflammatory syndrome (IRIS).

CONCLUSIONS

A clinical picture consistent with tuberculous meningitis includes constitutional symptoms, foreign birth, lymphocytic pleocytosis, specific radiographic findings, and immunodeficiency. Workup for tuberculous meningitis should include MRI, HIV screening, and cerebral spinal fluid analysis. It is essential to treat co-infection with HIV and to assess for IRIS.

Evolution of Cryptococcal Antigen Testing: What is new?

Over the last decade, an upsurge in both the frequency and severity of fungal infections due to the HIV/AIDS epidemic and the use of immunosuppressive therapy has occurred. Even diagnostic methods like culture and microscopy, which have low sensitivity and longer turn-around-times are not widely available, leading to delays in timely antifungal therapy and detrimental patient outcomes. The evolution of cryptococcal antigen (CrAg) testing to develop inexpensive and more sensitive methods to detect cryptococcal antigen is significant. These newer tests employ immunoassays as part of point-of-care platforms, which do not require complex laboratory infrastructure and they have the potential to detect early disease and reduce time to diagnosis of cryptococcal infection. Advocacy for widely available and efficacious life-saving antifungal treatment should be the only remaining challenge.

ISOLATION OF Cryptococcus neoformans FROM ENVIRONMENTAL SAMPLES COLLECTED IN SOUTHEASTERN NIGERIA

Cryptococcosis caused by Cryptococcus neoformans is the second most common fungal opportunistic pathogen and a life-threatening infection with serious clinical manifestations especially in HIV/AIDS and other immunocompromised patients. In Nigeria, HIV/AIDS infection has reached an alarming level. Despite this, information on the presence of this fungus in clinical and environmental samples is very scanty in Nigeria and many other parts of Africa. We set out to evaluate the presence of Cryptococcus neoformans or C. gattiiin pigeon droppings obtained from Southeastern Nigeria. One hundred and seventy-seven samples of pigeon droppings from six sample types were collected. The area covered comprised of ten cities and other locations spanning across five States in Nigeria. Using established techniques, Cryptococcus neoformans was isolated from 39 of the 177 (22.0%) samples overall. No C. gattiiwas isolated. Most of the isolates (32.4%) were recovered from dovecotes (11 of 34) followed closely by samples taken from markets (31.8%; seven of 22) and least from the church (4.0%; one of 25). The highest isolation rate (38.9%) was found in samples from Enugu-Ezike(seven of 23) while the least came from Afikpo and the other locations each with 9.1% isolation rate. This is the first large-scale screening of Cryptococcus neoformans from pigeon droppings in Nigeria. The ecological and epidemiological significance of these findings are discussed.

Management of severe non-TB bacterial infection in HIV-infected adults

Despite widespread antiretroviral therapy use, severe bacterial infections (SBI) in HIV-infected adults continue to cause significant morbidity and mortality globally. Four main pathogens account for the majority of documented SBI: Streptococcus pneumoniae, non-typhoidal strains of Salmonella enterica, Escherichia coli and Staphylococcus aureus. The epidemiology of SBI is dynamic, both in developing countries where, despite dramatic successes in antiretroviral therapy, coverage is far from complete, and in settings in both resource-poor and resource-rich countries where antiretroviral therapy failure is becoming increasingly common. Throughout the world, this complexity is further compounded by rapidly emerging antimicrobial resistance, making management of SBI very challenging in these vulnerable patients. We review the causes and treatment of SBI in HIV-infected people and discuss future developments in this field.

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.

The immunopathogenesis of cryptococcal immune reconstitution inflammatory syndrome: understanding a conundrum

PURPOSE OF REVIEW

Cryptococcal meningitis causes significant mortality among HIV-infected patients, despite antifungal therapy and use of antiretroviral therapy (ART). In patients with cryptococcal meningitis, ART is often complicated by immune reconstitution inflammatory syndrome (IRIS), manifesting as unmasking of previously unrecognized subclinical infection (unmasking CM-IRIS) or paradoxical worsening of symptoms in the central nervous system after prior improvement with antifungal therapy (paradoxical CM-IRIS). We review our current understanding of the pathogenesis of this phenomenon, focusing on unifying innate and adaptive immune mechanisms leading to the development of this often fatal syndrome.

RECENT FINDINGS

We propose that HIV-associated CD4 T-cell depletion, chemokine-driven trafficking of monocytes into cerebrospinal fluid in response to cryptococcal meningitis, and poor localized innate cytokine responses lead to inadequate cryptococcal killing and clearance of the fungus. Subsequent ART-associated recovery of T-cell signaling and restored cytokine responses, characterized by IFN-γ production, triggers an inflammatory response. The inflammatory response triggered by ART is dysregulated because of impaired homeostatic and regulatory mechanisms, culminating in the development of CM-IRIS.

SUMMARY

Despite our incomplete understanding of the immunopathogenesis of CM-IRIS, emerging data exploring innate and adaptive immune responses could be exploited to predict, prevent and manage CM-IRIS and associated morbid consequences.

Interleukin-17 mediated differences in the pathogenesis of HIV-1-associated tuberculous and cryptococcal meningitis

OBJECTIVE

Mycobacterium tuberculosis and Cryptococcus neoformans are major causes of meningitis in HIV-1-infected patients. Identifying differences in the inflammatory profiles of HIV-1-associated tuberculous meningitis (TBM) and cryptococcal meningitis may inform differences in immunopathogenic mechanisms in these diseases. In this study we compared the clinical and inflammatory features of HIV-1-associated TBM, and cryptococcal meningitis.

METHODS

A prospective study of HIV-1-infected adults who presented with either TBM [antiretroviral therapy (ART)-naive] or cryptococcal meningitis (regardless of ART prescription). Clinical and laboratory findings and concentrations of 40 inflammatory mediators measured in cerebrospinal fluid (CSF, 33 paired with blood) were compared between TBM and cryptococcal meningitis patients regardless of ART prescription and between TBM and cryptococcal meningitis patients not receiving ART.

RESULTS

Clinical and laboratory findings were similar in TBM (n=34) and cryptococcal meningitis (n = 19; ART prescribed: n = 10, no ART prescribed: n = 9). Exceptions included a higher median CD4 cell count [interquartile: 113 (69-199) vs. 25 (8-49) cells/μl, P = 0.0001] and higher HIV-1 median viral load [plasma: 5.46 (4.82-5.89) vs. 4.87 (4.36-5.17) log10copies/ml, P = 0.037; CSF: 6.05 (5.43-6.56) vs. 5.56 (4.52-5.80) log10copies/ml, P = 0.03] in TBM vs. cryptococcal meningitis patients not receiving ART. CSF interleukin (IL)-17A was lower in TBM compared with cryptococcal meningitis [1.00 (0.25-2.35) vs. 9.31 (1.24-23.36) pg/ml, P-adjusted = 0.03].

CONCLUSION

Despite presenting with higher peripheral CD4 cell counts, TBM patients also presented with higher HIV-1 viral loads compared with cryptococcal meningitis patients, suggesting a greater propensity of M. tuberculosis compared with C. neoformans to increase HIV-1 replication in vivo. CSF IL-17A was lower in TBM; its role in the immunopathogenesis of TBM and cryptococcal meningitis deserves further research.

Diagnostic performance of a multiplex PCR assay for meningitis in an HIV-infected population in Uganda

Meningitis remains a worldwide problem, and rapid diagnosis is essential to optimize survival. We evaluated the utility of a multiplex PCR test in differentiating possible etiologies of meningitis. Cerebrospinal fluid (CSF) from 69 HIV-infected Ugandan adults with meningitis was collected at diagnosis (n=51) and among persons with cryptococcal meningitis during therapeutic lumbar punctures (n=68). Cryopreserved CSF specimens were analyzed with BioFire FilmArray® Meningitis/Encephalitis panel, which targets 17 pathogens. The panel detected Cryptococcus in the CSF of patients diagnosed with a first episode of cryptococcal meningitis by fungal culture with 100% sensitivity and specificity and differentiated between fungal relapse and paradoxical immune reconstitution inflammatory syndrome in recurrent episodes. A negative FilmArray result was predictive of CSF sterility on follow-up lumbar punctures for cryptococcal meningitis. EBV was frequently detected in this immunosuppressed population (n=45). Other pathogens detected included: cytomegalovirus (n=2), varicella zoster virus (n=2), human herpes virus 6 (n=1), and Streptococcus pneumoniae (n=1). The FilmArray Meningitis/Encephalitis panel offers a promising platform for rapid meningitis diagnosis.

Spectrum of imaging appearances of intracranial cryptococcal infection in HIV/AIDS patients in the anti-retroviral therapy era

Cryptococcus neoformans infection is the most common fungal infection of the central nervous system (CNS) in advanced human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) patients, but remains a relatively uncommon CNS infection in both the immunocompromised and immunocompetent patient population, rendering it a somewhat elusive and frequently overlooked diagnosis. The morbidity and mortality associated with CNS cryptococcal infection can be significantly reduced by early recognition of the imaging appearances by the radiologist in order to focus and expedite clinical management and treatment. The emergence and evolution of anti-retroviral therapy have also impacted significantly on the imaging appearances, morbidity, and mortality of this neuro-infection. The constellation of varied imaging appearances associated with cryptococcal CNS infection in the HIV and AIDS population in the era of highly active anti-retroviral therapy (HAART) will be presented in this review.

Clinical Presentation, Aetiology, and Outcomes of Meningitis in a Setting of High HIV and TB Prevalence

Meningitis causes significant morbidity and mortality globally. The aim of this study was to study the clinical presentation, aetiology, and outcomes of meningitis among adult patients admitted to Queen Mamohato Memorial Hospital in Maseru, Lesotho, with a diagnosis of meningitis. A cross-sectional study was conducted between February and April 2014; data collected included presenting signs and symptoms, laboratory results, and clinical outcomes. Descriptive statistics were used to summarise data; association between variables was analysed using Fisher's exact test. 56 patients were enrolled; the HIV coinfection rate was 79%. The most common presenting symptoms were altered mental status, neck stiffness, headache, and fever. TB meningitis was the most frequent diagnosis (39%), followed by bacterial (27%), viral (18%), and cryptococcal meningitis (16%). In-hospital mortality was 43% with case fatalities of 23%, 40%, 44%, and 90% for TB, bacterial, cryptococcal, and viral meningitis, respectively. Severe renal impairment was significantly associated with mortality. In conclusion, the causes of meningitis in this study reflect the high prevalence of HIV and TB in our setting. Strategies to reduce morbidity and mortality due to meningitis should include improving diagnostic services to facilitate early detection and treatment of meningitis and timely initiation of antiretroviral therapy in HIV-infected patients.

Evaluation of fingerstick cryptococcal antigen lateral flow assay in HIV-infected persons: a diagnostic accuracy study

BACKGROUND

Cryptococcus neoformans is the most common cause of adult meningitis in sub-Saharan Africa. The cryptococcal antigen (CRAG) lateral flow assay (LFA) has simplified diagnosis as a point-of-care test approved for serum or cerebrospinal fluid (CSF). We evaluated the accuracy of the CRAG LFA using fingerstick whole blood compared with serum/plasma and CSF for diagnosing meningitis.

METHODS

From August 2013 to August 2014, CRAG LFA (IMMY, Norman, Oklahoma) tests were performed on fingerstick whole blood, plasma/serum, and CSF in 207 HIV-infected adults with suspected meningitis in Kampala, Uganda. Venous blood was also collected and centrifuged to obtain serum and/or plasma. CSF was tested after lumbar puncture.

RESULTS

Of 207 participants, 149 (72%) had fingerstick CRAG-positive results. There was 100% agreement between fingerstick whole blood and serum/plasma. Of the 149 fingerstick CRAG-positive participants, 138 (93%) had evidence of cryptococcal meningitis with a positive CSF CRAG. Eleven participants (5%) had isolated cryptococcal antigenemia with a negative CSF CRAG and culture, of whom 8 had CSF abnormalities (n = 3 lymphocytic pleocytosis, n = 5 elevated protein, n = 4 increased opening pressure). No persons with cryptococcal meningitis had negative fingersticks.

CONCLUSIONS

The 100% agreement between whole blood, serum, and plasma CRAG LFA results demonstrates that fingerstick CRAG is a reliable bedside diagnostic test. Using point-of-care CRAG testing simplifies screening large numbers of patients and enables physicians to prioritize on whom to measure CSF opening pressure using manometers.

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.

Evaluation of screening and treatment of cryptococcal antigenaemia among HIV-infected persons in Soweto, South Africa

OBJECTIVES

We retrospectively evaluated clinic-based screening to determine the prevalence of cryptococcal antigenaemia and management and outcome of patients with antigenaemia.

METHODS

Cryptococcal antigen (CrAg) screening of HIV-infected adults who attended the HIV clinic at Chris Hani Baragwanath Hospital was conducted over 19 months. Data collected from CrAg-positive patients included CD4 T-lymphocyte count at screening, prior or subsequent cryptococcal meningitis (CM), antifungal and antiretroviral treatment and outcome after at least 8 months.

RESULTS

Of 1460 patients with no prior CM, 30 (2.1%) had a positive CrAg test. The prevalence of antigenaemia among patients with a CD4 count < 100 cells/μl and no prior CM was 2.8% (20 of 708). Of 29 evaluable CrAg-positive patients with no prior CM, 14 (48%) did not return for post-screening follow-up. Of these 14, five developed CM and one (7%) was known to be alive at follow-up. Of 15 patients who returned for follow-up, two already had evidence of nonmeningeal cryptococcosis. Overall, 11 received fluconazole, one did not and fluconazole treatment was unknown for three. Among these 15, one developed CM and 10 (67%) were known to be alive at follow-up. Overall, 18 (62%) of 29 CrAg-positive patients died or were lost to follow-up. Seven (0.5%) of 1430 CrAg-negative patients developed CM a median of 83 days post-screening (range 34 to 219 days).

CONCLUSIONS

Loss to follow-up is the major operational issue relevant to scale-up of screen-and-treat. Patient outcomes may be improved by rapid access to CrAg results and focus on linkage to and retention in HIV care.

Comparative effectiveness of induction therapy for human immunodeficiency virus-associated cryptococcal meningitis: a network meta-analysis

Background.  Multiple international treatment guidelines recommend amphotericin-based combination regimens for induction therapy of cryptococcal meningitis. Yet, only 1 trial has reported a mortality benefit for combination amphotericin-flucytosine, and none have reported a mortality benefit for combination amphotericin-fluconazole. Methods.  We conducted a Bayesian network meta-analysis to estimate the comparative effectiveness of recommended induction therapies for HIV-associated cryptococcal meningitis. We searched PubMed and Cochrane CENTRAL for clinical reports of induction therapy for HIV-associated cryptococcal meningitis. We extracted or calculated early (two-week) and late (six to 12-week) mortality by treatment arm for the following induction regimens: amphotericin B alone, amphotericin B + flucytosine, amphotericin B + triazoles, amphotericin B + flucytosine +triazoles, triazoles alone, triazoles + flucytosine, liposomal amphotericin B, and amphotericin B + other medicines. Results.  In the overall sample (35 studies, n = 2483), we found no evidence of decreased mortality from addition of flucytosine or triazoles to amphotericin B, compared with amphotericin B alone. Although we did find a nonsignificant benefit for addition of flucytosine to amphotericin B in studies including participants with altered levels of consciousness, we did not identify a benefit for combination therapy in restricted analyses in either resource-rich or resource-limited settings, studies conducted before or after 2004, and studies restricted to a high dose of amphotericin B and fluconazole. Conclusions.  Given considerations of drug availability and toxicity, there is an important need for additional data to clarify which populations are most likely to benefit from combination therapies for human immunodeficiency virus-associated cryptococcal meningitis.

Leu1 plays a role in iron metabolism and is required for virulence in Cryptococcus neoformans

Amino acid biosynthetic pathways that are absent in mammals are considered an attractive target for antifungal therapy. Leucine biosynthesis is one such target pathway, consisting of a five-step conversion process starting from the valine precursor 2-keto-isovalerate. Isopropylmalate dehydrogenase (Leu1) is an Fe-S cluster protein that is required for leucine biosynthesis in the model fungus Saccharomyces cerevisiae. The human pathogenic fungus Cryptococcus neoformans possesses an ortholog of S. cerevisiae Leu1, and our previous transcriptome data showed that the expression of LEU1 is regulated by iron availability. In this study, we characterized the role of Leu1 in iron homeostasis and the virulence of C. neoformans. We found that deletion of LEU1 caused leucine auxotrophy and that Leu1 may play a role in the mitochondrial-cytoplasmic Fe-S cluster balance. Whereas cytoplasmic Fe-S protein levels were not affected, mitochondrial Fe-S proteins were up-regulated in the leu1 mutant, suggesting that Leu1 mainly influences mitochondrial iron metabolism. The leu1 mutant also displayed increased sensitivity to oxidative stress and cell wall/membrane disrupting agents, which may have been caused by mitochondrial dysfunction. Furthermore, the leu1 mutant was deficient in capsule formation and showed attenuated virulence in a mouse inhalation model of cryptococcosis. Overall, our results indicate that Leu1 plays a role in iron metabolism and is required for virulence in C. neoformans.

Cellular immune activation in cerebrospinal fluid from ugandans with cryptococcal meningitis and immune reconstitution inflammatory syndrome

Background. Human immunodeficiency virus (HIV)-associated cryptococcal meningitis (CM) is characterized by high fungal burden and limited leukocyte trafficking to cerebrospinal fluid (CSF). The immunopathogenesis of CM immune reconstitution inflammatory syndrome (IRIS) after initiation of antiretroviral therapy at the site of infection is poorly understood.

Methods. We characterized the lineage and activation status of mononuclear cells in blood and CSF of HIV-infected patients with noncryptococcal meningitis (NCM) (n = 10), those with CM at day 0 (n = 40) or day 14 (n = 21) of antifungal therapy, and those with CM-IRIS (n = 10).

Results. At diagnosis, highly activated CD8⁺ T cells predominated in CSF in both CM and NCM. CM-IRIS was associated with an increasing frequency of CSF CD4⁺ T cells (increased from 2.2% to 23%; P = .06), a shift in monocyte phenotype from classic to an intermediate/proinflammatory, and increased programmed death ligand 1 expression on natural killer cells (increased from 11.9% to 61.6%, P = .03). CSF cellular responses were distinct from responses in peripheral blood.

Conclusions. After CM, T cells in CSF tend to evolve with the development of IRIS, with increasing proportions of activated CD4⁺ T cells, migration of intermediate monocytes to the CSF, and declining fungal burden. These changes provide insight into IRIS pathogenesis and could be exploited to more effectively treat CM and prevent CM-IRIS.

Determination of the minimum inhibitory concentration of Cryptococcus neoformans and Cryptococcus gattii against fluconazole by flow cytometry

Recent studies have used flow cytometry (FCM) as an important alternative method to determine the antifungal susceptibility of yeasts compared to the broth microdilution Clinical and Laboratory Standards Institute (CLSI) reference procedure. We present a comparative study of the broth microdilution method and flow cytometry to assess the in vitro antifungal susceptibility of Cryptococcus neoformans (n = 16) and C. gattii (n = 24) to fluconazole. The minimum inhibitory concentration (MIC) assays by flow cytometry were defined as the lowest drug concentration that showed ∼50% of the count of acridine orange negative cells compared to that of the growth control. Categorical classification showed all C. neoformans isolates were susceptible to fluconazole. Three isolates of C. gattii were susceptible dose-dependent and the remaining 21 isolates were classified as susceptible. MICs comparison of both methodologies demonstrated 100% categorical agreement of the results obtained for C. neoformans and C. gattii. The MICs obtained with the CLSI-approved method and flow cytometry were compared by the Spearman correlation test and a significant Pv = 0.001. The flow cytometric method has the advantage of analyzing a large and constant number of cells in less time, i.e., 9 h incubation for fluconazole using acridine orange versus 72 h for broth microdilution method. In conclusion, the two methods were comparable and flow cytometry method can expedite and improve the results of in vitro susceptibility tests of C. neoformans and C. gattii against fluconazole and also allows comparative studies in vitro/in vivo more rapidly, which along with clinical data, could assist in selecting the most appropriate treatment choice.