HIV-associated opportunistic CNS infections: pathophysiology, diagnosis and treatment

The Prospect of Nanoparticle Systems for Modulating Immune Cell Polarization During Central Nervous System Infection

The blood-brain barrier (BBB) selectively restricts the entry of molecules from peripheral circulation into the central nervous system (CNS) parenchyma. Despite this protective barrier, bacteria and other pathogens can still invade the CNS, often as a consequence of immune deficiencies or complications following neurosurgical procedures. These infections are difficult to treat since many bacteria, such as Staphylococcus aureus, encode a repertoire of virulence factors, can acquire antibiotic resistance, and form biofilm. Additionally, pathogens can leverage virulence factor production to polarize host immune cells towards an anti-inflammatory phenotype, leading to chronic infection. The difficulty of pathogen clearance is magnified by the fact that antibiotics and other treatments cannot easily penetrate the BBB, which requires extended regimens to achieve therapeutic concentrations. Nanoparticle systems are rapidly emerging as a promising platform to treat a range of CNS disorders. Nanoparticles have several advantages, as they can be engineered to cross the BBB with specific functionality to increase cellular and molecular targeting, have controlled release of therapeutic agents, and superior bioavailability and circulation compared to traditional therapies. Within the CNS environment, therapeutic actions are not limited to directly targeting the pathogen, but can also be tailored to modulate immune cell activation to promote infection resolution. This perspective highlights the factors leading to infection persistence in the CNS and discusses how novel nanoparticle therapies can be engineered to provide enhanced treatment, specifically through modulation of immune cell polarization.

Strategies for the diagnosis and management of meningitis in HIV-infected adults in resource limited settings

INTRODUCTION

The incidence of human immunodeficiency virus-1 (HIV-1) associated meningitis has been declining in the post-combination antiretroviral treatment (ART) era, although survival rates remain low for the common causes like tuberculosis and cryptococcal disease. Diagnosis and treatment of meningitis in HIV-1 is complicated by atypical clinical presentations, limited accuracy of diagnostic tests, access to diagnostic tests, and therapeutic agents in low- and middle-income countries (LMIC) and immune reconstitution inflammatory syndrome (IRIS).

AREAS COVERED

We provide an overview of the common etiologies of meningitis in HIV-1-infected adults, suggest a diagnostic approach based on readily available tests, and review specific chemotherapeutic agents, host-directed therapies, supportive care, timing of ART initiation, and considerations in the management of IRIS with a focus on resource-limited settings. They identify key knowledge gaps and suggest areas for future research.

EXPERT OPINION

Evidence-based management of HIV-1-associated meningitis is sparse for common etiologies. More readily available and sensitive diagnostic tests as well as standardized investigation strategies are required in LMIC. There is a lack of availability of recommended drugs in areas of high HIV-1 prevalence and a limited pipeline of novel chemotherapeutic agents. Host-directed therapies have been inadequately studied.

How SARS-CoV-2 and Other Viruses Build an Invasion Route to Hijack the Host Nucleocytoplasmic Trafficking System

The host nucleocytoplasmic trafficking system is often hijacked by viruses to accomplish their replication and to suppress the host immune response. Viruses encode many factors that interact with the host nuclear transport receptors (NTRs) and the nucleoporins of the nuclear pore complex (NPC) to access the host nucleus. In this review, we discuss the viral factors and the host factors involved in the nuclear import and export of viral components. As nucleocytoplasmic shuttling is vital for the replication of many viruses, we also review several drugs that target the host nuclear transport machinery and discuss their feasibility for use in antiviral treatment.

Molecular and microscopic prevalence of intestinal microsporidia among HIV+/AIDS patients in the Alborz province, Iran

BACKGROUND

Microsporidia are a large family of obligate intracellular protozoa; these medically important species are recognized as opportunistic agents in intestinal complications in HIV+/AIDS patients.

METHODS

The current cross-sectional study was designed and conducted from October 2018 to June 2019 to determine intestinal microsporidia in HIV+/AIDS patients by trichrome/Zeihl-Neelsen staining and SYBR Green-based real-time PCR.

RESULTS

Out of 80 HIV+/AIDS patients, 23.75% (n=19) and 12.5% (n=10) were identified by molecular and microscopic methods, respectively. The predominant species in patients was Encephalitozoon (94%), which was found by quantitative real-time PCR and its high resolution melting tool.

CONCLUSION

As far as we know, this is the first report from the Alborz region. The prevalence of intestinal microsporidiosis in this area in HIV+/AIDS patients was higher than both the global and national average. In addition to the need for further studies to prove protozoan pathogenicity in the aforementioned group, preventive measures should be considered.

Treatment of toxoplasmic encephalitis with the combination of clindamycin plus azithromycin in an HIV-infected patient: A case report

The existence of alternative oral therapies could help clinicians to treat toxoplasmic encephalitis (TE) in the HIV patients. The combination of azithromycin and clindamycin may serve as an effective treatment for TE in HIV-infected patients.

Clinical usefulness of metagenomic next-generation sequencing for the diagnosis of central nervous system infection in people living with HIV

OBJECTIVES

To evaluate the clinical utility of metagenomic next-generation sequencing (mNGS) for the diagnosis of central nervous system (CNS) infection in people living with human immunodeficiency virus (PLWH) in a real-world situation.

METHODS

Cerebrospinal fluid (CSF) was sent for mNGS for PLWH who tested negative on all conventional tests but were still suspected to have CNS infection. A retrospective analysis was undertaken of the results and the clinical effect of mNGS on this cohort. The final diagnosis was adjudicated by a panel discussion following hospital discharge when the results of all tests and patients' responses to the empiric therapy were available.

RESULTS

Eighty-eight eligible PLWH, including 51 (58%) patients suspected of encephalitis and 34 (46.7%) patients suspected of meningitis, were included in the analysis. Sixty-eight (77.3%) patients were diagnosed with CNS infection, of which 50 were based on the pathogens identified by mNGS. The most common disease missed by mNGS was clinically suspected tuberculous meningitis, followed by clinically suspected non-tuberculous mycobacterial meningitis. The results from mNGS led to modification of treatment in 21 (23.9%) patients, and increased confidence in continuation of original therapy in 30 (34.1%) patients. During hospitalization, two (2.3%) patients died and 66 (75%) patients improved.

CONCLUSIONS

mNGS of CSF is a useful tool for the diagnosis of CNS infection among PLWH. Further investigations are warranted to improve its sensitivity.

Current State and Promising Opportunities on Pharmaceutical Approaches in the Treatment of Polymicrobial Diseases

In recent years, the emergence of newly identified acute and chronic infectious disorders caused by diverse combinations of pathogens, termed polymicrobial diseases, has had catastrophic consequences for humans. Antimicrobial agents have been clinically proven to be effective in the pharmacological treatment of polymicrobial diseases. Unfortunately, an increasing trend in the emergence of multi-drug-resistant pathogens and limited options for delivery of antimicrobial drugs might seriously impact humans' efforts to combat polymicrobial diseases in the coming decades. New antimicrobial agents with novel mechanism(s) of action and new pharmaceutical formulations or delivery systems to target infected sites are urgently required. In this review, we discuss the prospective use of novel antimicrobial compounds isolated from natural products to treat polymicrobial infections, mainly via mechanisms related to inhibition of biofilm formation. Drug-delivery systems developed to deliver antimicrobial compounds to both intracellular and extracellular pathogens are discussed. We further discuss the effectiveness of several biofilm-targeted delivery strategies to eliminate polymicrobial biofilms. At the end, we review the applications and promising opportunities for various drug-delivery systems, when compared to conventional antimicrobial therapy, as a pharmacological means to treat polymicrobial diseases.

Application of Pathogen Discovery/Metagenomic Sequencing in CNS HIV

PURPOSE OF REVIEW

Neurological conditions associated with HIV/AIDS including central nervous system (CNS), opportunistic infections (OI), chronic conditions including HIV-associated neurocognitive disorder, and cerebrospinal fluid (CSF) viral escape remain major contributors to morbidity and mortality worldwide. CNS infections in HIV-infected patients are often challenging to diagnose by traditional microbiological testing, impacting treatment and outcome.

RECENT FINDINGS

Recent advances in diagnostic techniques, including metagenomic next-generation sequencing (mNGS), are changing the landscape of microbiological testing, mainly in resource-rich settings. Pathogen discovery techniques offer a hypothesis-free approach to diagnostic testing, yielding comprehensive analysis of microbial genetic material. Given the extent of genetic material produced, deep sequencing tools not only hold promise in the diagnosis of CNS infections but also in defining key pathogenic steps which have previously been unanswered. Significant challenges remain to implementing pathogen discovery techniques in routine clinical practice including cost, expertise and infrastructure needed including laboratory and bioinformatics support, and sample contamination risk. The use in resource-limited regions where the burden of CNS complications due to HIV/AIDS is highest remains poorly defined. Though, major opportunities utilizing pathogen discovery techniques exist to enhance surveillance and diagnosis and improve our understanding of mechanisms of neuroinvasion in CNS conditions associated with HIV.

A comparative study of multimodal magnetic resonance in the differential diagnosis of acquired immune deficiency syndrome related primary central nervous system lymphoma and infection

Background

Patients with acquired immune deficiency syndrome (AIDS) often suffer from opportunistic infections and related primary central nervous system lymphoma (AR-PCNSL). Both diseases showed multiple ring enhancement lesions in conventional magnetic resonance (MR). It is very difficult to make the differential diagnosis. We aimed to investigate whether multimodal MR (diffusion weighted imaging (DWI)/ apparent diffusion coefficient (ADC), 3D pseudo-continuous arterial spin labeling (3D-pCASL) and susceptibility-weighted imaging (SWI)) combined with conventional MR can differentiate AR-PCNSL from infections.

Methods

This was a prospective study. We recruited 19 AIDS patients who were divided into AR-PCNSL group (9 cases) and infection group (10 cases) by pathological results. We analyzed whether there was statistical (Fisher’s method) difference in multimodal MR between the two groups. We analyzed whether multimodal MR combined with conventional MR could improve the diagnosis of AR-PCNSL.

Results

The lesions were more likely involved the paraventricular (0.020) and corpus callosum (0.033) in AR-PCNSL group in conventional MR. In multimodal MR, AR-PCNSL group showed low ADC value, with p values of 0.001. Infection group more inclined to high ADC value, with p was 0.003. In multimodal MR, AR-PCNSL group had more low signal intensity (grade 2–3) in the degree of intratumoral susceptibility signal intensity in SWI (SWI-ITSS), with p values of 0.001. The sensitivity, specificity of conventional MR in the diagnosis of AR-PCNSL was 88.9 and 70.0%. The conventional MR sequence combined with DWI/ADC sequence in the diagnosis of AR-PCNSL had a sensitivity of 100.0%, and a specificity of 60.0%. The sensitivity and specificity of the conventional MR sequence combined with the SWI-ITSS sequence in the diagnosis of AR-PCNSL were 100 and 70.0%. The conventional MR combined with ADC or SWI-ITSS improved the diagnosis of AR-PCNSL.

Conclusion

Multimodal MR could distinguish AR-PCNSL from infectious lesions. The multimodal MR (DWI/ADC or SWI-ITSS) combined with conventional MR could improve the diagnosis of AR-PCNSL. The ADC value should be attached importance in clinical work. When distinguishing AR-PCNSL from toxoplasmosis or tuberculoma, SWI should be used to obtain a correct diagnosis.

Immune Privilege: The Microbiome and Uveitis

Immune privilege (IP), a term introduced to explain the unpredicted acceptance of allogeneic grafts by the eye and the brain, is considered a unique property of these tissues. However, immune responses are modified by the tissue in which they occur, most of which possess IP to some degree. The eye therefore displays a spectrum of IP because it comprises several tissues. IP as originally conceived can only apply to the retina as it contains few tissue-resident bone-marrow derived myeloid cells and is immunologically shielded by a sophisticated barrier – an inner vascular and an outer epithelial barrier at the retinal pigment epithelium. The vascular barrier comprises the vascular endothelium and the glia limitans. Immune cells do not cross the blood-retinal barrier (BRB) despite two-way transport of interstitial fluid, governed by tissue oncotic pressure. The BRB, and the blood-brain barrier (BBB) mature in the neonatal period under signals from the expanding microbiome and by 18 months are fully established. However, the adult eye is susceptible to intraocular inflammation (uveitis; frequency ~200/100,000 population). Uveitis involving the retinal parenchyma (posterior uveitis, PU) breaches IP, while IP is essentially irrelevant in inflammation involving the ocular chambers, uveal tract and ocular coats (anterior/intermediate uveitis/sclerouveitis, AU). Infections cause ~50% cases of AU and PU but infection may also underlie the pathogenesis of immune-mediated “non-infectious” uveitis. Dysbiosis accompanies the commonest form, HLA-B27–associated AU, while latent infections underlie BRB breakdown in PU. This review considers the pathogenesis of uveitis in the context of IP, infection, environment, and the microbiome.

The clinical characteristics and outcome of cryptococcal meningitis with AIDS in a tertiary hospital in China: an observational cohort study

BACKGROUND

Despite the profound impact of antiretroviral therapy in the control of AIDS mortality, central nervous system opportunistic infections remains a significant burden in AIDS patients. This retrospective study aims to elucidate the clinical characteristics, outcome and risk factors of cryptococcal meningitis (CM) poor prognosis in AIDS patients from a tertiary hospital in China.

METHODS

Clinical data from 128 patients admitted in Beijing Ditan Hospital, Capital Medical University from November 2008 to November 2017 was collected. The cohort was stratified based on treatment outcome (effective 79%, and ineffective 21%), and Multivariate Logistic regression analysis used to identify risk factors of poor disease prognosis.

RESULTS

Age, incidence of cerebral infarction, the proportion of consciousness disorder, and fasting plasma glucose was higher in the ineffective treatment group than the effective treatment group. The duration of treatment in the induction period of the ineffective group was significantly shorter than that of the effective group. Multivariate Logistic regression analysis indicated that the occurrence of cerebral hernia and consciousness disorder were risk factors for the prognosis of AIDS patients with CM infection, while the duration of treatment in the induction period was a indicative of a better prognosis in AIDS with CM infection complications. Finally, shunt decompression therapy correlated with a better disease outcome.

CONCLUSIONS

This retrospective study exposes the main risk factors associated with worse disease prognosis in AIDS patients with CM infection complications.

The Prevalence of Frascati-Criteria-Based HIV-Associated Neurocognitive Disorder (HAND) in HIV-Infected Adults: A Systematic Review and Meta-Analysis

Background: The HIV associated mortality is decreasing in most countries due to the widespread use of antiretroviral therapy. However, HIV-associated neurocognitive disorder (HAND) remains a problematic issue that lowers the quality of life and increases the public health burden among people living with HIV. The prevalence of HAND varies across studies and selected samples. Therefore, we aimed to quantitatively summarize the pooled prevalence of Frascati-criteria-based HAND and to explore the potential demographic, clinical, and immunological factors. Methods: A comprehensive literature search in PubMed/Medline, Web of Science, Embase, and PsycINFO was performed. A random-effects meta-analysis was conducted using the event rate (ER) for the estimation of the incidence of HAND. Subgroup meta-analyses were used to evaluate between-group differences in categorical variables. Meta-regression with the unrestricted maximum likelihood (ML) method was used to evaluate associations of continuous variables. Results: Eighteen studies whose sample sizes ranged from 206 to 1555 were included in the final analyses. The estimated prevalence of HAND, ANI, MND and HAD were 44.9% (95% CI 37.4-52.7%), 26.2% (95% CI 20.7-32.7%), 8.5% (95% CI 5.6-12.7%), 2.1% (95% CI 1.2-3.7%), respectively. Factors associated with HAND were percent female, current CD4 count, education level and country development level (all ps < 0.05). Conclusion: Longitudinal cohort and multimodal neuroimaging studies are needed to verify the clinical prognosis and the underlying neurocognitive mechanism of HAND. In addition, it is urgently necessary to establish a standardized HAND diagnostic process.

Foodborne transmission of Toxoplasma gondii infection in the last decade. An overview

Toxoplasmosis is a zoonotic disease of global distribution and importance. It is caused by the protozoan parasite Toxoplasma gondii, the only species in the Toxoplasma genus. This parasite can infect most warm-blooded animals, including humans and livestock. Main routes of transmission are by ingestion of tissue cysts in raw or undercooked meat of infected animals, ingestion of raw vegetables or water contaminated with T. gondii oocysts from cat feces, and transplacental. Around one-third of human beings are chronically infected with T. gondii. Most infections appear to be asymptomatic in immunocompetent persons, but toxoplasmosis can be fatal to the fetus and immunocompromised adults. Water and foodborne outbreaks have been caused by this parasite worldwide, but few are well documented. Importantly, T. gondii is a parasite of high importance in animal health, causing reproductive failure, particularly in small ruminants, and clinical toxoplasmosis in many species. This overview discusses the knowledge of T. gondii infections in the last decade focusing on the foodborne transmission of this parasite.

Th1-Dependent Cryptococcus-Associated Immune Reconstitution Inflammatory Syndrome Model With Brain Damage

Cryptococcus-associated immune reconstitution inflammatory syndrome (C-IRIS) is identified upon immune reconstitution in immunocompromised patients, who have previously contracted an infection of Cryptococcus neoformans (Cn). C-IRIS can be lethal but how the immune system triggers life-threatening outcomes in patients is still poorly understood. Here, we establish a mouse model for C-IRIS with Cn serotype A strain H99, which is highly virulent and the most intensively studied. C-IRIS in mice is induced by the adoptive transfer of CD4+ T cells in immunocompromised Rag1-deficient mice infected with a low inoculum of Cn. The mice with C-IRIS exhibit symptoms which mimic clinical presentations of C-IRIS. This C-IRIS model is Th1-dependent and shows host mortality. This model is characterized with minimal lung injury, but infiltration of Th1 cells in the brain. C-IRIS mice also exhibited brain swelling with resemblance to edema and upregulation of aquaporin-4, a critical protein that regulates water flux in the brain in a Th1-dependent fashion. Our C-IRIS model may be used to advance our understanding of the paradoxical inflammatory phenomenon of C-IRIS in the context of neuroinflammation.

Progressive multifocal leukoencephalopathy in an HIV patient was diagnosed by 3 times lumbar punctures and 2 times brain biopsies

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease of the central nervous system caused by JC virus (JCV) and is difficult to diagnose. We report on a male HIV-positive patient with PML finally diagnosed by 3 times lumbar punctures and 2 times brain biopsies. Negative results of JCV-PCR in cerebrospinal fluid (CSF) do not rule out the diagnosis of PML when clinical manifestations and neuroimaging features suspected PML. It is necessary to obtain new CSF and make repeat tests and even perform brain biopsy.

18F-FDG PET/CT in Tuberculosis: Can Interim PET/CT Predict the Clinical Outcome of the Patients?

PURPOSE OF THE REPORT

Tuberculosis (TB) is a major health problem. Activated macrophages in TB lesions show high metabolic activity and can be assessed using F-FDG PET/CT. This retroprospective study was done to evaluate the utility of F-FDG PET/CT in initial assessment and therapeutic response in patients with TB.

MATERIALS AND METHODS

Eighty-seven patients (male-to-female ratio, 46:41) diagnosed with pulmonary TB and extrapulmonary TB underwent whole-body F-FDG PET/CT for initial assessment and a follow-up scan 3 to 4 months after initiation of antitubercular therapy (ATT). Visual and semiquantitative (SUVmax) analyses were used for scan assessment. Treatment responses on interim scans were categorized as complete metabolic response (CMR), favorable response to therapy (FRT), stable disease (SD), and disease progression (DP). CMR, FRT, and SD cases were considered as responders and DP cases as nonresponders. Treatment response was correlated with clinical outcome (mortality) and ATT duration.

RESULTS

Baseline F-FDG PET/CT scans were positive in all the patients and detected additional disease sites than suspected clinically in 72% patients. On interim PET/CT, 13 patients showed CMR, 43 showed FRT, 8 showed SD, and 23 showed DP. A longer duration of ATT was seen in nonresponders (P ≤ 0.001) than responders. During follow-up, 9/87 patients died, out of which 8 patients were of DP group and 1 patient belonged to SD. Nonresponders showed 35% mortality compared with 1.6% in the responder group (P ≤ 0.001).

CONCLUSIONS

F-FDG PET/CT is a valuable imaging modality for disease mapping and assessing therapeutic response. Treatment response in the interim PET/CT done at 3 to 4 months predicted the duration of ATT and clinical outcome of the patients.

Approach to an Intracranial Mass in Patients With HIV

PURPOSE OF REVIEW

Space-occupying lesions represent a diagnostic challenge among people with the human immunodeficiency virus, acquired immunodeficiency syndrome (HIV/AIDS). To determine the best diagnostic approach to the wide array of possible etiologies and provide a thorough interpretation of neuroimaging in order to narrow a hierarchical differential diagnosis among these patients. Given that there is no pathognomonic neuroimaging pattern in this clinical setting, we searched results from brain biopsies to best determine the etiology of commonly found lesions.

RECENT FINDINGS

Multimodal brain MRI and MRI spectroscopy (MRS) often provide the most valuable information in the study of focal masses among people with HIV/AIDS. Brain biopsy appears safe and provides high diagnostic yields in these patients. Among patients with HIV/AIDS who present with space-occupying intracranial lesions, brain MRI and MRS are useful tests. However, in cases of diagnostic uncertainty, brain biopsy is a safe procedure and should be performed. The role of metabolic studies like ²⁰¹Th-SPECT or PET is useful in the detection of primary central nervous system lymphoma.

Neuroimaging Insights Into Early Stages of HIV-Progressive Multifocal Leukoencephalopathy: A Case Report

This report aims to enhance the understanding of early longitudinal neuroimaging features of progressive multifocal leukoencephalopathy (PML) in human immunodeficiency virus (HIV). Neuroimaging has become crucial in the diagnosis and early recognition of PML. Recognition of magnetic resonance imaging (MRI) features in the early stages of PML is paramount to avoid misdiagnosis and facilitate the delivery of treatments aimed at reducing disease progression. A 49-year-old white man with HIV presented with 4-month progressive left-sided weakness. Neurological examination revealed mild cognitive impairment, left-sided hemiparesis, and somatosense impairment to all modalities. Brain MRI revealed a punctate pattern with innumerable T2-FLAIR (fluid attenuated inversion recovery) hyperintensities in the cortex, brainstem, cerebellum, subcortical, and periventricular areas. Susceptibility-weighted imaging (SWI) revealed hypointensities involving subcortical U-fibers and cortical architecture. A comprehensive diagnostic evaluation was inconclusive. John Cunningham virus (JCV) PCR in cerebrospinal fluid (CSF) was indeterminate. He was started on antiretroviral therapy. Repeat brain MRI performed 1.5 months later, in the setting of further neurological decline, demonstrated progression of the T2-hyperintensities into a large confluent white matter lesion in the right frontoparietal lobe. Despite an indeterminate JCV PCR, the appearance and characteristic progression of the lesions in successive imaging in the setting of severe immunosuppression, with extensive negative infectious workup, was indicative of PML. This clinical experience illustrates unique neuroimaging features of HIV-PML in early stages and its progression over time. It especially highlights the relevance of the SWI sequence in the diagnosis and features observed with disease evolution. Short-term imaging follow-up may assist with the recognition of MRI features consistent with the biology of the infection.

A study for precision diagnosing and treatment strategies in difficult-to-treat AIDS cases and HIV-infected patients with highly fatal or highly disabling opportunistic infections: Study protocol for antiretroviral therapy timing in AIDS patients with toxoplasma encephalitis

BACKGROUND

Toxoplasma encephalitis (TE) is one of the main opportunistic infections in acquired immunodeficiency syndrome (AIDS) patients, and represents a social burden due to its high prevalence and morbidity. Concomitant antiretroviral therapy (ART), together with effective anti- toxoplasma combination therapy, is an effective strategy to treat AIDS-associated TE (AIDS/TE) patients. However, the timing for the initiation of ART after diagnosis of TE remains controversial. We therefore designed the present study to determine the optimal timing for ART initiation in AIDS/TE patients.

METHODS/DESIGN

This trial is a 17-center, randomized, prospective clinical study with 2 parallel arms. A total of 200 participants will be randomized at a 1:1 ratio into the 2 arms: the early ART initiation (≤14 days after TE diagnosis) arm and the deferred ART (>14 days after TE diagnosis) arm. The primary outcome will be the difference of mortality between the 2 arms at 48 weeks. The secondary outcomes will be the differences between the 2 arms in the changes of CD4+ counts from baseline to week 48, the rate of virologic suppression (HIV ribonucleic acid <50 copies/mL) from baseline to week 48, the incidence of TE-associated immune reconstitution inflammatory syndrome during the study period, and the incidence of adverse effects during the study period.

DISCUSSION

This present trial aims to evaluate the optimal timing for ART initiation in AIDS/TE patients, and will provide strong evidence for AIDS/TE treatment should it be successful.

TRIAL REGISTRATION

This trial was registered as one of the 12 trials under the name of a general project at the chictr.gov (http://www.chictr.org.cn/showproj.aspx?proj=35362) on February 1, 2019, and the registration number of the general project is ChiCTR1900021195.

Optimizing Pyrazolopyrimidine Inhibitors of Calcium Dependent Protein Kinase 1 for Treatment of Acute and Chronic Toxoplasmosis

Calcium dependent protein kinase 1 (CDPK1) is an essential Ser/Thr kinase that controls invasion and egress by the protozoan parasite Toxoplasma gondii. The Gly gatekeeper of CDPK1 makes it exquisitely sensitive to inhibition by small molecule 1H-pyrazolo[3,4-d]pyrimidine-4-amine (PP) compounds that are bulky ATP mimetics. Here we rationally designed, synthesized, and tested a series of novel PP analogs that were evaluated for inhibition of CDPK1 enzyme activity in vitro and parasite growth in cell culture. Optimal substitution on the PP scaffold included 2-pyridyl ethers directed into the hydrophobic pocket and small carbocyclic rings accessing the ribose-binding pocket. Further optimization of the series led to identification of the lead compound 3a that displayed excellent potency, selectivity, safety profile, and efficacy in vivo. The results of these studies provide a foundation for further work to optimize CDPK1 inhibitors for the treatment of acute and chronic toxoplasmosis.

HIV Testing in Adults Presenting With Central Nervous System Infections

Background

Universal HIV testing in adults presenting to a health care setting was recommended by the Centers for Disease Control and Prevention (CDC) in 2006, but compliance in central nervous system (CNS) infections is unknown.

Methods

A multicenter study of adults presenting with CNS infections to 18 hospitals in Houston and New Orleans between 2000 and 2015 was done to characterize HIV testing and explore factors associated with a positive HIV test.

Results

A total of 1478 patients with a diagnosis of meningitis or encephalitis were identified; 180 were excluded because of known HIV diagnosis (n = 100) or were <17 years old (n = 80). Out of 1292 patients, 642 (49.7%) had HIV testing, and testing did not differ significantly before or after the CDC recommendations in 2006 (53% vs 48%; P = .068). An HIV test was more commonly done in patients who were non-Caucasian, had fever >38°C, or had seizures on presentation, and of those tested, non-Caucasian patients and those with photophobia were more likely to have a positive HIV test (P < .05). HIV testing also varied by type of CNS infection: community-acquired bacterial meningitis (98/130, 75.4%), encephalitis (174/255, 68.2%), aseptic meningitis (285/619, 46.0%), and health care–associated meningitis (85/288, 29.5%; P < .001).

Conclusions

Even though HIV testing should be done in all adults presenting with a CNS infection, testing remains ~50% and did not improve after the recommendation for universal testing by the CDC in 2006.

Toxoplasma gondii Seropositivity and Associated Risk Factors in Cats (Felis catus) in Three Provinces in Northeastern China from 2013 to 2019

Toxoplasma gondii is an important protozoan parasite that can infect a range of animals. Cats are the most important definitive hosts for T. gondii. Therefore, an assessment of the level of T. gondii infection in cats is of public health importance. As limited information about seroprevalence of T. gondii infection in cats in northeastern China was available, 854 serum samples, including 235 cats in Jilin province, 267 cats in Liaoning province, and 352 cats in Heilongjiang province, were examined by an indirect hemagglutination assay (IHA) test, between September 2013 and July 2019. The overall seroprevalence of T. gondii was 19.09% (163/854) at the cutoff 1:64, with 19.60% (69/352), 18.29% (43/235), and 19.10% (51/267) in Heilongjiang, Jilin and Liaoning, respectively. Logistic regression analysis showed that mode of life was highly related to T. gondii infection in cats at the investigation areas. These results could provide foundation data for prevention and control of T. gondii prevalence in these regions. Moreover, the results also suggested that the effective control strategies should continue to be performed.

Disease of the Year 2019: Ocular Toxoplasmosis in HIV-infected Patients

Ocular toxoplasmosis (OT) may be an initial manifestation of acquired immunodeficiency syndrome (AIDS) in human immunodeficiency virus (HIV)-infected patients. OT has different clinical manifestations and can mimic other intraocular infections. Clinical findings may show single or multifocal retinochoroidal lesions or panuveitis. Atypical presentations are associated with extensive uni- or bilateral areas of retinal necrosis. OT lesions not associated with preexisting retinochoroidal scars are usually due to acquired rather than congenital infection. When CD4+ T cell counts are <100 c/uL, vitritis is frequently mild. Isolated anterior uveitis has been reported in single cases. Positive immunoglobulin M (IgM) antibodies are rare but their presence can support the diagnosis. As atypical presentations of OT are common, anterior chamber puncture for multiplex polymerase chain reaction amplification of infectious DNA should be considered, as early diagnosis and treatment can prevent massive tissue destruction and preserve vision. This review provides an overview of OT in HIV-infected patients.

Molecular and Histologic Diagnosis of Central Nervous System Infections

Infections of the central nervous system cause significant morbidity and mortality in immunocompetent and immunocompromised individuals. A wide variety of microorganisms can cause infections, including bacteria, mycobacteria, fungi, viruses, and parasites. Although less invasive testing is preferred, surgical biopsy may be necessary to collect diagnostic tissue. Histologic findings, including special stains and immunohistochemistry, can provide a morphologic diagnosis in many cases, which can be further classified by molecular testing. Correlation of molecular, culture, and other laboratory results with histologic findings is essential for an accurate diagnosis, and to minimize false positives from microbial contamination.

Purine and pyrimidine transporters of pathogenic protozoa - conduits for therapeutic agents

Purines and pyrimidines are essential nutrients for any cell. Most organisms are able to synthesize their own purines and pyrimidines, but this ability was lost in protozoans that adapted to parasitism, leading to a great diversification in transporter activities in these organisms, especially for the acquisition of amino acids and nucleosides from their hosts throughout their life cycles. Many of these transporters have been shown to have sufficiently different substrate affinities from mammalian transporters, making them good carriers for therapeutic agents. In this review, we summarize the knowledge obtained on purine and pyrimidine activities identified in protozoan parasites to date and discuss their importance for the survival of these parasites and as drug carriers, as well as the perspectives of developments in the field.

Fulminant central nervous system varicella-zoster virus infection unexpectedly diagnosed by metagenomic next-generation sequencing in an HIV-infected patient: a case report

BACKGROUND

Varicella-zoster virus (VZV) infection can be diagnosed clinically once classical rash occurs but the diagnosis is challenging when typical rash is absent. We reported a case of fulminant central nervous system (CNS) VZV infection in a human immunodeficiency virus (HIV)-infected patient without typical VZV-related rash. CNS VZV infection was unexpected identified by metagenomic next-generation sequencing (mNGS).

CASE PRESENTATION

A 28-year-old HIV-infected patient presented with neurological symptoms for 3 days. The patient, who was not suspected of VZV infection at admission, quickly progressed to deep coma during the first 24 h of hospitalization. An unbiased mNGS was performed on DNA extract from 300 μL cerebrospinal fluid (CSF) with the BGISEQ-50 platform. The sequencing detection identified 97,248 (out of 38,561,967) sequence reads uniquely aligned to the VZV genome, and these reads covered a high percentage (99.91%) of the VZV. Presence of VZV DNA in CSF was further verified by VZV-specific polymerase chain reaction and Sanger sequencing. Altogether, those results confirmed CNS VZV infection.

CONCLUSIONS

This study suggests that mNGS may be a useful diagnostic tool for CNS VZV infection. As mNGS could identify all pathogens directly from CSF sample in a single run, it has the promise of strengthening our ability to diagnose CNS infections in HIV-infected patients.

Neuro-Ophthalmic Manifestations of HIV Infection

Purpose: To review the broad spectrum of clinical neuro-ophthalmic presentations associated with human immunodeficiency virus (HIV) infection. Methods: Critical review of the literature regarding neuro-ophthalmic consequences of HIV infection and its sequelae. Results: Neuro-ophthalmological diseases are common in both asymptomatic HIV-positive patients and those who profound immunosuppression with acquired immune deficiency syndrome (AIDS). Neuro-ophthalmic manifestations of HIV infection can involve the afferent or efferent visual pathway. Common clinical presentations include headache, papilledema, chorioretinitis, optic nerve involvement, meningitis, and cranial nerve palsies. Other neuro-ophthalmic manifestations include involvement of the visual pathway in the brain producing visual field defects such as occur in progressive multifocal encephalopathy. Pupil abnormalities have also been reported. Discussion: Neuro-ophthalmic consequences of HIV are important to recognize as it is critical to identify underlying neoplastic or infectious diseases which could be amenable to treatment.

Comparison of the RE-529 sequence and B1 gene for Toxoplasma gondii detection in blood samples of the at-risk seropositive cases using uracil DNA glycosylase supplemented loop-mediated isothermal amplification (UDG-LAMP) assay

Diagnosis of toxoplasmosis is an important issue, especially in at-risk patients. The molecular methods showed a promising future for such diagnosis; however, the method itself and the target sequence to be detected is an important part of accurate detection of the infection. The aim of the present study was to evaluate the RE-529 sequence and B1 gene for Toxoplasma gondii detection in blood samples of the at-risk seropositive cases using uracil DNA glycosylase supplemented loop-mediated isothermal amplification (UDG-LAMP) assay. In this study, 110 T. gondii seropositive at-risk individuals (pregnant women and immunocompromised patients) and 110 seronegative controls were enrolled. The two most studied sequences (RE-529 and B1) were used and compared for accurate and reliable detection of T. gondii in blood samples using UDG-LAMP assay and compared with real-time PCR method. The detection limit, accuracy, and reliability of UDG-LAMP for the parasite's DNA were also studied. Among 110 studied cases, 39 (35.45%) and 36 (32.7%) were positive for T. gondii DNA with the RE-LAMP and B1-LAMP, respectively. The seronegative cases remained negative for T. gondii DNA with the studied genes, however, there were few false negatives compared with real-time PCR method. The detection limit of the UDG-LAMP for both DNA targets was 0.16 tachyzoite's DNA per reaction tube. Based on the results of this study, the RE-529 sequence has a better detection rate compared to the B1 gene for toxoplasmosis among at-risk people. UDG-LAMP is a highly sensitive, accurate, and reliable method with no false-positive results for the diagnosis of T. gondii infection in blood specimens, however few cases may be missed.

Progressive Multifocal Leukoencephalopathy Diagnosed by Metagenomic Next-Generation Sequencing of Cerebrospinal Fluid in an HIV Patient

Metagenomic next-generation sequencing (mNGS) is a novel approach to identify pathogens undetected by conventional methods. Herein, we report a case in which mNGS was used to identify JC virus from the cerebrospinal fluid sample of an HIV positive patient with progressive multifocal leukoencephalopathy (PML).

Isolation, identification, and phylogenetic analysis of potentially pathogenic free-living amoebae isolated from nasal and oral mucosa of HIV/AIDS patients in Iran

The burden of HIV/AIDS in Iran is not as high as in the other countries with high prevalence; however, the number of cases of HIV/AIDs is increasing in this region. According to a recent report, Iran had 5000 (1400-13,000) new cases of HIV infection with 4000 (2500-6200) AIDS-related deaths. Individuals affected by HIV/AIDS are highly susceptible for developing opportunistic infections, e.g. the cerebral complications related to pathogenic free-living amoebae and colonization of free-living amoebae (FLA) can be a serious hazard for patients living with HIV/AIDS. In the present study, a total of 70 oral and nasal mucosal samples were obtained from HIV/AIDS patients referred to the reference hospitals in Iran and tested for the presence of potentially pathogenic FLA using culture and PCR/sequencing-based methods. To discern the taxonomic status of Acanthamoeba genotypes a maximum likelihood phylogenetic tree was constructed and tolerance assays were performed for the positive Acanthamoeba strains. Among the patients with HIV/AIDS referred to the reference hospitals from 2017 to 2019, 7.1% were found positive for pathogenic free-living amoebae. Three strains (HA3, HA4, and HA5) belonged to the T4 genotype, one strain (HA1) was related to the T5 genotype assigned as A. lenticulata, and another strain (HA2) had high homology to Vermamoeba vermiformis. The tolerance assay used for Acanthamoeba strains (HA1, HA3, and HA4) classified these amoebae as highly pathogenic strains. For the most part, the encephalitis cases occurring in HIV/AIDS patients in Iran remain undiagnosed due to lack of awareness of the practitioners on the available diagnostic tools for this lethal infection; therefore, the true incidence of GAE in this region is unknown. A possible colonization with FLA should be considered in the differential diagnosis of suspected cases of CNS infections among HIV/AIDS patients. This study is the first worldwide comprehensive study attempting to isolate and identify the FLA colonization in HIV/AIDS patients. This study highlights the fact that clinicians should be aware of the differential diagnosis of cerebral disease related to FLA in patients with HIV/AIDS.

Serological and molecular rapid diagnostic tests for Toxoplasma infection in humans and animals

Infection by Toxoplasma gondii is prevalent worldwide. The parasite can infect a broad spectrum of vertebrate hosts, but infection of fetuses and immunocompromised patients is of particular concern. Easy-to-perform, robust, and highly sensitive and specific methods to detect Toxoplasma infection are important for the treatment and management of patients. Rapid diagnostic methods that do not sacrifice the accuracy of the assay and give reproducible results in a short time are highly desirable. In this context, rapid diagnostic tests (RDTs), especially with point-of-care (POC) features, are promising diagnostic methods in clinical microbiology laboratories, especially in areas with minimal laboratory facilities. More advanced methods using microfluidics and sensor technology will be the future trend. In this review, we discuss serological and molecular-based rapid diagnostic tests for detecting Toxoplasma infection in humans as well as animals.

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.

Mortality by cryptococcosis in Brazil from 2000 to 2012: A descriptive epidemiological study

BACKGROUND

Cryptococcosis is a neglected and predominantly opportunistic mycosis that, in Brazil, poses an important public health problem, due to its late diagnosis and high lethality.

METHODS

The present study analysed cryptococcosis mortality in Brazil from January 2000 to December 2012, based on secondary data (Mortality Information System/SIM-DATASUS and IBGE).

RESULTS

Out of 5,755 recorded deaths in which cryptococcosis was mentioned as one of the morbid states that contributed to death, two distinct groups emerged: 1,121 (19.5%) registered cryptococcosis as the basic cause of death, and 4,634 (80.5%) registered cryptococcosis associated with risk factors, mainly AIDS (75%), followed by other host risks (5.5%). The mortality rate by cryptococcosis as the basic cause was 6.19/million inhabitants, whereas the mortality rate by cryptococcosis as an associated cause was 25.19/million inhabitants. Meningitis was the predominant clinical form (80%), males were the more affected (69%), and 39.5 years old was the mean age. The highest mortality rate due to cryptococcosis as basic cause occurred in the state of Mato Grosso (10.96/million inhabitants). Mortality rates due to cryptococcosis as associated cause were highest in the states of Santa Catarina (70.41/million inhabitants) and Rio Grande do Sul (64.40/million inhabitants), both in the South Region. Southeast, Northeast and South showed significant time trends in mortality rates.

CONCLUSIONS

This study is relevant because it shows the magnitude of cryptococcosis mortality linked to AIDS and removes the invisibility of a particular non-AIDS-related disease, accounting for almost 20% of all cryptococcosis deaths. It can also contribute to control and surveillance programs, beyond highlighting the urgent prioritization of early diagnosis and proper treatment to reduce the unacceptable mortality rate of this neglected mycosis in Brazil.

Merkel Cell Carcinoma in the HIV-1/AIDS Patient

Merkel cell carcinoma (MCC) is a highly aggressive, primary neuroendocrine cancer of the skin. The majority of MCC cases are associated with the recently discovered Merkel cell polyomavirus (MCPyV), while the remaining are caused by ultraviolet (UV) light-induced mutations from excessive sunlight exposure. The risk of developing MCC is much higher in the white population relative to all other races. Approximately 10% of all patients with MCC have some form of immunosuppression including HIV-1/AIDS, chronic inflammatory conditions, solid organ transplantation, or hematological malignancies. The age of onset of MCC is lower and the mortality is higher in immunosuppressed individuals than in immune-competent patients. It is plausible that HIV-1/AIDS predisposes to virus-positive MCC, but it should be noted that HIV-1/AIDS increases the risk for developing of UV-induced skin cancers such as cutaneous squamous cell carcinoma and basal cell carcinoma and therefore may also increase the risk for virus-negative MCC. Surgical management is considered standard of care for localized Merkel cell carcinoma with current recommendations advising a wide local excision of the lesion. Most international guidelines support the use of local adjuvant radiotherapy coupled with tumor staging to improve the frequency of cure. For advanced, metastatic, and recurrent MCC, checkpoint blockade inhibitors targeting PD-1 and PD-L1 have shown remarkable activity including durable long-term. MCC in patients living with HIV-1/AIDS are treated with similar modalities as HIV-1 uninfected individuals with MCC.

Pathogen Analysis of Central Nervous System Infections in a Chinese Teaching Hospital from 2012-2018: A Laboratory-based Retrospective Study

Central nervous system (CNS) infections are associated with high mortality rates. The clinical presentation of many CNS infections by different pathogens is difficult to distinguish, but the definite diagnosis of the etiology is critical for effective therapy and prognosis. The aim of this study was to explore the etiology of CNS infections with definite diagnoses based on data from a clinical microbiology laboratory in Tongji Hospital, a teaching hospital in China, obtained over a six-year period. We conducted a retrospective study on all cerebrospinal fluid (CSF) specimens submitted to our clinical microbiology laboratory from September, 2012 to December, 2018. The etiology of CNS infections caused by Cryptococcus neoformans, Mycobacterium tuberculosis and common bacteria was analyzed. Antimicrobial susceptibility testing was conducted on all isolates. The results showed that 1972 cases of CNS infections were identified from 18 300 CSF specimens. Common bacterial meningitis (BM), cryptococcal meningitis (CM) and tuberculous meningitis (TM) accounted for 86.3% (677/785), 9.4% (74/785) and 4.3% (34/785) respectively of cases over the six-year period. BM was the most common among the different age groups, followed by CM. Of the TM cases, 44.1% (15/34) were distributed within the age group of 15-34 years, whereas for CM cases, 52.7% (39/74) occurred within the 35-54-year age group, and the age distribution of BM cases was fairly even. Among the bacterial pathogens isolated, Staphylococcus epidermidis was the most common, accounting for 12.5% (98/785), followed by Acinetobacter baumannii (ABA) and Staphylococcus aureus (SAU), accounting for 11.8% (93/785) and 7.6% (60/785) respectively. The resistance rates to antibiotics were >75%, with the exception of the resistance rate of ABA to tegafycline, which was <3%. More than 60% of SAU strains displayed resistance to penicillin, oxacillin, ampicillin/sulbactam, cefazolin, cefuroxime, gentamycin, tobramycin, erythromycin and levofloxacin, whereas more than 90% of SAU strains showed susceptibility to trimethoprim/sulfamethoxazole, tegafycline, vancomycin, teicoplanin and linezolid. For C. neoformans, the susceptibility rates to amphotericin B, 5-fluorocytosine, fluconazol and voriconazole were >95%. Analysis of samples from patients with CNS infection in a clinical microbiology laboratory at a teaching hospital in China over a six-year period indicated that the most common etiological agents were the bacteria ABA and SAU. The antibiotic resistance levels of ABA were found to be high and of concern, whereas isolates of C. neoformans were found to be sensitive to antifungal antibiotics.

Factors Associated with Immune Discordant Responses in Treated HIV-infected Omani Patients

Background:

Despite sustained viral control by antiretroviral therapy (ART), some HIV-infected patients do not recover normal CD4+ T cell counts. This Discordant Immune Response (DIR) increases the risk of opportunistic infections.

Objective:

To evaluate the factors associated with DIR in HIV-infected Omani patients attending public sector clinics.

Methods:

All HIV-infected patients receiving ART with regular follow-up visits were eligible for this study. The DIR group comprised patients on ART for at least two years with plasma HIV viral load < 50 copies/mL and helper CD4+ T cell counts below 350 cells/μl. The Concordant Immune Responses (CIR) group was similar to DIR but with CD4+ T cell counts above 350 cells/μl. Univariate and multivariate analyses using logistic regression models were used to assess the impact of demographic characteristics, clinical, immunological and virological parameters, type of ART regimens, tuberculosis and other opportunistic co-infections on DIR.

Results:

Among 153 enrolled participants, 28 and 76 patients were identified as having DIR and CIR, respectively. The multivariate analysis revealed that the only factors independently associated with DIR after adjustment were age (odds ratio [OR] 1.13; 95% confidence interval [CI] 1.04-1.23), baseline CD4+ T cell count (OR: 0.98; CI: 0.97-0.99) and baseline CD56+ cell count (OR: 0.97; CI: 0.96-0.99).

Conclusion:

Collectively, these findings suggest that a significant proportion of HIV-infected Omani patients develop DIR totaling 27%, and efforts should be made to improve early identification of these patients who tend to experience poor clinical outcomes.

The global and regional prevalence, burden, and risk factors for methicillin-resistant Staphylococcus aureus colonization in HIV-infected people: A systematic review and meta-analysis

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is among the most important opportunistic pathogens in HIV+ patients, resulting in considerable morbidity and mortality.

METHODS

The MEDLINE, Scopus, Web of Science, and EMBASE databases were comprehensively searched for studies that investigated the prevalence of MRSA colonization in HIV+ patients. We used a random effects model to calculate pooled prevalence estimates with 95% confidence intervals (CI) and analyzed data based on World Health Organization regions.

RESULTS

Among 9,772 records identified, 69 were included in the meta-analysis, comprising 30,050 HIV+ patients from 21 countries. We estimated the pooled worldwide prevalence of MRSA in people living with HIV to be 7% (95% CI 5%-9%, 1,623/30,050), with the highest prevalence in Southeast Asia (16%, 95% CI 9%-24%) and the region of the Americas (10%; 95% CI 7%-13%) and lowest prevalence in the European region (1%; 95% CI 0%-1%). Globally, we estimated approximately 2,659,000 (95% CI 1,835,000-3,303,000) HIV+ patients with colonized MRSA. Potential risk factors for MRSA colonization in HIV+ patients included previous MRSA infection (OR, 7.5; 95% CI, 3.91-14.37), hospitalization in the past year (OR, 1.87; 95% CI 1.11-3.16), and use of antibiotics (OR, 2.52; 95% CI 1.39-4.58).

CONCLUSIONS

Our findings emphasize the importance of routine screening for MRSA among all HIV+ patients throughout the world, especially in regions that have a high burden of disease.

Utility of Whole-Genome Next-Generation Sequencing of Plasma in Identifying Opportunistic Infections in HIV/AIDS

Background:

AIDS-associated Opportunistic Infections (OIs) have significant morbidity and mortality and can be diagnostically challenging, requiring invasive procedures as well as a combination of culture and targeted molecular approaches.

Objective:

We aimed to demonstrate the clinical utility of Next-generation Sequencing (NGS) in pathogen identification; NGS is a maturing technology enabling the detection of miniscule amounts of cell-free microbial DNA from the bloodstream.

Methods:

We utilized a novel Next-generation Sequencing (NGS) test on plasma samples to diagnose a series of HIV-associated OIs that were diagnostically confirmed through conventional microbial testing.

Results:

In all cases, NGS test results were available sooner than conventional testing. This is the first case series demonstrating the utility of whole-genome NGS testing to identify OIs from plasma in HIV/AIDS patients.

Conclusion:

NGS approaches present a clinically-actionable, comprehensive means of diagnosing OIs and other systemic infections while avoiding the labor, expense, and delays of multiple tests and invasive procedures.

Resistance and Tolerance to Cryptococcal Infection: An Intricate Balance That Controls the Development of Disease

Cryptococcus neoformans is a ubiquitous environmental yeast and a leading cause of invasive fungal infection in humans. The most recent estimate of global disease burden includes over 200,000 cases of cryptococcal meningitis each year. Cryptococcus neoformans expresses several virulence factors that may have originally evolved to protect against environmental threats, and human infection may be an unintended consequence of these acquired defenses. Traditionally, C. neoformans has been viewed as a purely opportunistic pathogen that targets severely immune compromised hosts; however, during the past decade the spectrum of susceptible individuals has grown considerably. In addition, the closely related strain Cryptococcus gattii has recently emerged in North America and preferentially targets individuals with intact immunity. In parallel to the changing epidemiology of cryptococcosis, an increasing role for host immunity in the pathogenesis of severe disease has been elucidated. Initially, the HIV/AIDS epidemic revealed the capacity of C. neoformans to cause host damage in the absence of adaptive immunity. Subsequently, the development and clinical implementation of highly active antiretroviral treatment (HAART) led to recognition of an immune reconstitution inflammatory syndrome (IRIS) in a subset of HIV+ individuals, demonstrating the pathological role of host immunity in disease. A post-infectious inflammatory syndrome (PIIRS) characterized by abnormal T cell-macrophage activation has also been documented in HIV-negative individuals following antifungal therapy. These novel clinical conditions illustrate the highly complex host-pathogen relationship that underlies severe cryptococcal disease and the intricate balance between tolerance and resistance that is necessary for effective resolution. In this article, we will review current knowledge of the interactions between cryptococci and mammalian hosts that result in a tolerant phenotype. Future investigations in this area have potential for translation into improved therapies for affected individuals.

Lacunar Stroke in Cryptococcal Meningitis: Clinical and Radiographic Features

OBJECTIVE

Cryptococcal meningitis carries a high mortality, and survivors are left with considerable neurologic sequelae and marked disability. We lack a clear understanding of the pathogenesis of neurologic sequelae and description of stroke features in this population. We aim to describe clinical and radiographic features and predictors of stroke in a cohort of patients with cryptococcal meningitis.

METHODS

We collected key information on patients diagnosed with cryptococcal meningitis at the University of Colorado Hospital between 2000 and 2018 (n = 42). Of those, 32 had neuroimaging studies available. Bivariate and risk ratio estimates regression models were performed to identify predictors of stroke.

RESULTS

We found a 26% ischemic stroke complication rate in individuals with cryptococcal meningitis. Most strokes were acute (75%), lacunar (100%), multiple (88%), bilateral (63%), and involving the basal ganglia (75%). Presence of malignancy (38% versus 8%, P = .085) was higher in stroke in individuals with cryptococcal meningitis, although not statistically significant. Every unit decrease in hemoglobin and serum sodium were predictors for 1.35 and 1.14 times increase in the risk of ischemic stroke, respectively. The presence of hyponatremia carried a RR of 5.7 (95% confidence interval, 1.7-34, P = .005). Cryptococcal meningitis lead to death in 19% of patients and a considerable rate of neurologic sequela among survivors.

CONCLUSIONS

Cryptococcal meningitis carries a high risk of lacunar stroke, particularly in the basal ganglia. Cryptococcal meningitis-associated stroke is common and frequently associated with neurologic disability among survivors. We need to understand the possible role of malignancy, anemia, and hyponatremia in the onset of ischemic stroke.

HIV-Related Cerebral Toxoplasmosis Revisited: Current Concepts and Controversies of an Old Disease

Cerebral toxoplasmosis is the most common cause of expansive brain lesions in people living with HIV/AIDS (PLWHA) and continues to cause high morbidity and mortality. The most frequent characteristics are focal subacute neurological deficits and ring-enhancing brain lesions in the basal ganglia, but the spectrum of clinical and neuroradiological manifestations is broad. Early initiation of antitoxoplasma therapy is an important feature of the diagnostic approach of expansive brain lesions in PLWHA. Pyrimethamine-based regimens and trimethoprim-sulfamethoxazole (TMP-SMX) seem to present similar efficacy, but TMP-SMX shows potential practical advantages. The immune reconstitution inflammatory syndrome is uncommon in cerebral toxoplasmosis, and we now have more effective, safe, and friendly combined antiretroviral therapy (cART) options. As a consequence of these 2 variables, the initiation of cART can be performed within 2 weeks after initiation of antitoxoplasma therapy. Herein, we will review historical and current concepts of epidemiology, diagnosis, and treatment of HIV-related cerebral toxoplasmosis.

Early emergence of opportunistic infections after starting direct-acting antiviral drugs in HIV/HCV-coinfected patients

Varicella-zoster virus and hepatitis B virus reactivations have been reported after starting interferon-free direct-acting antiviral agent (DAA) combinations. HIV/HCV-coinfected patients could be a high-risk group for the reactivation of latent infections. Because of these, we report the occurrence of severe infections after starting DAA regimens in HIV/HCV-coinfected patients. Individuals included in the HEPAVIR-DAA (NCT02057003) cohort were selected if they had received all-oral DAA combinations. A retrospective review of clinical events registered between the start of DAAs and 12 months after SVR12 was carried out. Overall, 38 (4.5%) of 848 patients presented infections. The incidence (95% confidence interval) of infections was 4.6 (3.3-6.3) cases per 100 person-years. The median (Q1-Q3) time to the infection since baseline was 23 (7.3-33) weeks. Five (13%) of the patients with infections died; four of them had cirrhosis. The frequency of previous AIDS was 21 (54%) for patients with infections and 324 (40%) for those without infections (P = 0.084). The median (Q1-Q3) nadir CD4 cell count of individuals with and without infections was 75 (53-178) and 144 (67-255) cells/μL, respectively (P = 0.047). Immunodepression-associated infections were observed in 9 (1.1%) patients. All of them had suppressed HIV replication with antiretroviral therapy. In conclusion, severe infections are relatively common among HIV/HCV-coinfected patients receiving all-oral DAA combinations. Some unusual reactivations of latent infections in patients with suppressed HIV replication seem to be temporally linked with DAA use.

Metagenomic next-generation sequencing as a diagnostic tool for toxoplasmic encephalitis

BACKGROUND

More than 100 different pathogens can cause encephalitis. Testing of all the neurological pathogens by conventional methods can be difficult. Metagenomic next-generation sequencing (NGS) could identify the infectious agents in a target-independent manner. The role of this novel method in clinical diagnostic microbiology still needs to be evaluated. In present study, we used metagenomic NGS to search for an infectious etiology in a human immunodeficiency virus (HIV)-infected patient with lethally diffuse brain lesions. Sequences mapping to Toxoplasma gondii were unexpectedly detected.

CASE PRESENTATION

A 31-year-old HIV-infected patient presented to hospital in a critical ill condition with a Glasgow coma scale score of 3. Brain magnetic resonance imaging showed diffuse brain abnormalities with contrast enhancement. Metagenomic NGS was performed on DNA extract from 300 μL patient's cerebrospinal fluid (CSF) with the BGISEQ-50 platform. The sequencing detection identified 65,357 sequence reads uniquely aligned to the Toxoplasma gondii genome. Presence of Toxoplasma gondii genome in CSF was further verified by Toxoplasma gondii-specific polymerase chain reaction and Sanger sequencing. Altogether, those results confirmed the diagnosis of toxoplasmic encephalitis.

CONCLUSIONS

This study suggests that metagenomic NGS may be a useful diagnostic tool for toxoplasmic encephalitis. As metagenomic NGS is able to identify all pathogens in a single run, it may be a promising strategy to explore the clinical causative pathogens in central nervous system infections with atypical features.

Dual infection of the central nervous system caused by Cryptococcus and Toxoplasma in a patient with AIDS: a case report and literature review

Dual infection of the central nervous system secondary to Cryptococcus and Toxoplasma is very uncommon, even in the setting of acquired immunodeficiency syndrome (AIDS). We report the case of a 52-year-old patient who was admitted with multiple cranial nerve deficits. Magnetic resonance imaging showed supratentorial and infratentorial enhancing lesions. He was newly diagnosed with HIV infection with a CD4 count of 59 cells/uL and HIV viral load of 299,619 copies/mL. Diagnosis of Cryptococcus meningitis was made by Cryptococcal antigen in cerebrospinal fluid (CSF). The high clinical suspicion for Toxoplasmosis prompted an early empiric treatment for this condition. The diagnosis of Toxoplasmosis was later confirmed by PCR in CSF. Despite an adequate treatment for these two pathologies, his condition deteriorated and eventually expired. We reviewed the English language literature for cases of Cryptococcus and Toxoplasma co-infection of the central nervous system in patients with AIDS. To our knowledge, our patient is the third case of simultaneous infection described in the literature. Clinicians must be aware that focal brain lesions in patients with cryptococcal meningitis should prompt a full evaluation to search for concomitant pathologies of which Toxoplasmosis is the most important. Our case illustrates the utility of PCR in CSF for an early diagnosis of toxoplasmosis, reserving brain biopsy for cases of anti-toxoplasma therapy failure.

Shedding light on IRIS: from Pathophysiology to Treatment of Cryptococcal Meningitis and Immune Reconstitution Inflammatory Syndrome in HIV-Infected Individuals

OBJECTIVES

The aim of this work was to review current treatment options and propose alternatives for immune reconstitution inflammatory syndrome (IRIS) in HIV-infected individuals with cryptococcal meningitis (CM) (termed 'HIV-CM IRIS'). As a consequence of the immunocompromised state of these individuals, the initial immune response to CM is predominantly type 2 T helper (Th2) /Th17 rather than Th1, leading to inefficient fungal clearance at the time of antiretroviral initiation, and a subsequent overexaggeration of the Th1 response and life-threatening IRIS development.

METHODS

An article-based and clinical trial-based search was conducted to investigate HIV-CM IRIS pathophysiology and current treatment practices.

RESULTS

Guidelines for CM treatment, based on the Cryptococcal Optimal Antiretroviral Timing (COAT) trial, recommend delayed antiretroviral therapy (ART) following antifungal treatment. The approach aims to decrease fungal burden and allow immune balance restoration prior to ART initiation. If the initial immune balance is not restored, the fungal burden is not sufficiently reduced and there is a risk of developing IRIS post-ART, highlighted by a Th1 immune overcompensation, leading to increased mortality. The mainstay treatment for Th1-biased IRIS is corticosteroids; however, this treatment has been shown to correlate with increased mortality and significant associated adverse events. We emphasize targeting a more specific Th1 mechanism via the tumour necrosis factor (TNF)-α cytokine antagonist thalidomide, as it is the only TNF-α antagonist currently approved for use in infectious disease settings and has been shown to decrease Th1 overreaction, restoring immune balance in HIV-CM IRIS.

CONCLUSIONS

Although the side effects and limitations of thalidomide must be considered, it is currently being successfully used in infectious disease settings and warrants mainstream application as a therapeutic option for treatment of IRIS in HIV-infected patients with CM.