'Time-to-amphotericin B' in cryptococcal meningitis in a European low-prevalence setting: analysis of diagnostic delays

High prevalence of central nervous system cryptococcosis using a fingerprick whole-blood lateral flow assay in individuals with neurological symptoms and advanced HIV disease in a Brazilian emergency department

Timely diagnosis is key in managing central nervous system (CNS) cryptococcosis in people living with HIV/AIDS (PLWHA). There are few data on implementing fingerprick whole-blood cryptococcal antigen (CrAg) lateral flow assay (LFA) as the first test for diagnosing CNS cryptococcosis. We evaluated the prevalence of CNS cryptococcosis and cryptococcal antigenemia using fingerprick whole-blood in a referral emergency department (ED) in São Paulo, Brazil. This was a prospective cohort study of consecutive adult PLWHA with advanced HIV disease and neurological symptoms. Fingerprick whole-blood CrAg LFA was performed at bedside. Seventy-four individuals were enrolled (median age = 40 years; males = 62%). Prevalence of CNS cryptococcosis was 17.6% (13/74); 95% confidence interval (CI), 9.4-30.0%, and prevalence of positive fingerprick whole-blood CrAg LFA was 25.7% (19/74); 95% CI, 15.5-40.1%. Among the six (8.1%) patients with positive fingerprick whole-blood CrAg LFA and negative CSF CrAg LFA, four (5.4%) had isolated asymptomatic cryptococcal antigenemia, one (1.3%) had symptomatic cryptococcal antigenemia, and one (1.3%) had cryptococcemia. Prevalence of CNS cryptococcosis and cryptococcal antigenemia using fingerprick whole-blood CrAg LFA was high. Point-of-care testing was important for diagnosing CNS cryptococcosis in an ED from a middle-income country.

"False negative" CSF cryptococcal antigen with clinical meningitis: Case reports and review of literature

There is an increasing recognition of patients presenting with cryptococcal meningitis despite having a negative CSF cryptococcal antigen (CrAg). In this report, we describe three cases of patients with advanced immunosuppression who presented to hospital with "false negative" CSF cryptococcal antigen, two of whom had a positive fungal culture. We describe the challenge of CSF-CrAg negative cryptococcal meningitis and explore ways to overcome this challenge using newer diagnostic techniques.

Pathogen and host genetics underpinning cryptococcal disease

Cryptococcosis is a severe fungal disease causing 220,000 cases of cryptococcal meningitis yearly. The etiological agents of cryptococcosis are taxonomically grouped into at least two species complexes belonging to the genus Cryptococcus. All of these yeasts are environmentally ubiquitous fungi (often found in soil, leaves and decaying wood, tree hollows, and associated with bird feces especially pigeon guano). Infection in a range of animals including humans begins following inhalation of spores or aerosolized yeasts. Recent advances provide fundamental insights into the factors from both the pathogen and its hosts which influence pathogenesis and disease. The complex interactions leading to disease in mammalian hosts have also updated from the availability of better genomic tools and datasets. In this review, we discuss recent genetic research on Cryptococcus, covering the epidemiology, ecology, and evolution of Cryptococcus pathogenic species. We also discuss the insights into the host immune response obtained from the latest genetic modified host models as well as insights from monogenic disorders in humans. Finally we highlight outstanding questions that can be answered in the near future using bioinformatics and genomic tools.

Cognitive biases and knowledge deficits leading to delayed recognition of cryptococcal meningitis

Cryptococcal meningitis is a potentially devastating infectious complication of immunosuppression best characterized in individuals with HIV. Early recognition of and appropriate antifungal therapy for cryptococcal meningitis has a profound effect on outcomes, but with more varied presentations in well-resourced countries recognition may be delayed. We present four cases of cryptococcal meningitis in immunosuppressed patients, each with significant delays in diagnosis. Pulling from recollections of providers and the documented chart assessments, we discuss and tabulate the cognitive biases and diagnostic errors that contributed to delay. We further explore the knowledge deficits regarding cryptococcal meningitis that appeared in these cases. Once meningitis was considered, each of these cases of cryptococcal meningitis was rapidly diagnosed. Diagnostic delay was driven by knowledge deficits, followed by common biases such as availability heuristics and premature closing. These delays could be countered by maintaining broad differential diagnoses, re-evaluating the patient presentation after recognition of immunosuppression, and early consultation of specialists. Delay in diagnosis of cryptococcal meningitis is associated with high morbidity and mortality. By exploring the various case presentations and errors made, we hope to provide a counter to some of the knowledge deficits associated with cryptococcal meningitis, and to provide actionable advice for early consultation to infectious disease specialists in order to improve outcomes.

Molecular evolution of HIV-1 integrase during the 20 years prior to the first approval of integrase inhibitors

BACKGROUND

Detailed knowledge of the evolutionary potential of polymorphic sites in a viral protein is important for understanding the development of drug resistance in the presence of an inhibitor. We therefore set out to analyse the molecular evolution of the HIV-1 subtype B integrase at the inter-patient level in Germany during a 20-year period prior to the first introduction of integrase strand inhibitors (INSTIs).

METHODS

We determined 337 HIV-1 integrase subtype B sequences (amino acids 1-278) from stored plasma samples of antiretroviral treatment-naïve individuals newly diagnosed with HIV-1 between 1986 and 2006. Shannon entropy was calculated to determine the variability at each amino acid position. Time trends in the frequency of amino acid variants were identified by linear regression. Direct coupling analysis was applied to detect covarying sites.

RESULTS

Twenty-two time trends in the frequency of amino acid variants demonstrated either single amino acid exchanges or variation in the degree of polymorphy. Covariation was observed for 17 amino acid variants with a temporal trend. Some minor INSTI resistance mutations (T124A, V151I, K156 N, T206S, S230 N) and some INSTI-selected mutations (M50I, L101I, T122I, T124 N, T125A, M154I, G193E, V201I) were identified at overall frequencies >5%. Among these, the frequencies of L101I, T122I, and V201I increased over time, whereas the frequency of M154I decreased. Moreover, L101I, T122I, T124A, T125A, M154I, and V201I covaried with non-resistance-associated variants.

CONCLUSIONS

Time-trending, covarying polymorphisms indicate that long-term evolutionary changes of the HIV-1 integrase involve defined clusters of possibly structurally or functionally associated sites independent of selective pressure through INSTIs at the inter-patient level. Linkage between polymorphic resistance- and non-resistance-associated sites can impact the selection of INSTI resistance mutations in complex ways. Identification of these sites can help in improving genotypic resistance assays, resistance prediction algorithms, and the development of new integrase inhibitors.

Incidence, clinical presentation, and outcome of HIV-1-associated cryptococcal meningitis during the highly active antiretroviral therapy era: a nationwide cohort study

BACKGROUND

Human immunodeficiency virus (HIV) infection with advanced immunosuppression predisposes to cryptococcal meningitis (CM). We describe the incidence, clinical presentation, and outcome of CM in HIV-infected individuals during the highly active antiretroviral therapy (HAART) era.

METHODS

A nationwide, population-based cohort of HIV-infected individuals was used to estimate incidence and mortality of CM including risk factors. A description of neurological symptoms of CM at presentation and follow-up in the study period 1995-2014 was included in this study.

RESULTS

Among 6,351 HIV-infected individuals, 40 were diagnosed with CM. The incidence rates were 3.7, 1.8, and 0.3 per 1000 person-years at risk in 1995-1996, 1997-1999, and 2000-2014, respectively. Initiation of HAART was associated with decreased risk of acquiring CM [incidence rate ratio (IRR), 0.1 (95% CI, 0.05-0.22)]. African origin was associated with increased risk of CM [IRR, 2.05 (95% CI, 1.00-4.20)]. The main signs and symptoms at presentation were headache, cognitive deficits, fever, neck stiffness, nausea, and vomiting. All individuals diagnosed with CM had a CD4⁺ cell count <200 cells/µl [median 26; interquartile range (IQR), 10-50)]. Overall, mortality following CM was high and mortality in the first 4 months has not changed substantially over time. However, individuals who survived generally had a favorable prognosis, with 86% (18/21) returning to the pre-CM level of activity.

CONCLUSION

The incidence of HIV-associated CM has decreased substantially after the introduction of HAART. To further decrease CM incidence and associated mortality, early HIV diagnosis and HAART initiation seems crucial.

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.

Neuroimaging of HIV-associated cryptococcal meningitis: comparison of magnetic resonance imaging findings in patients with and without immune reconstitution

To determine the frequency, imaging characteristics, neuroanatomical distribution and dynamics of magnetic resonance imaging findings in HIV-associated cryptococcal meningitis in immunocompromised patients we compared patients without antiretroviral therapy with patients undergoing immune reconstitution. Neuroimaging and clinical data of 21 consecutive patients presenting to a German HIV centre in a 10-year period between 2005 and 2014 were reviewed. We identified eight patients with magnetic resonance imaging findings related to cryptococcal disease: five patients without antiretroviral therapy and three patients receiving effective antiretroviral therapy resulting in immune reconstitution. The pattern of magnetic resonance imaging manifestations was different in the two groups. In patients not on antiretroviral therapy, pseudocysts (n = 3) and lacunar ischaemic lesions (n = 2) were detected. Contrast-enhancing focal leptomeningeal and/or parenchymal lesions were found in all patients under immune reconstitution (n = 3). Magnetic resonance imaging lesions suggestive of leptomeningitis or meningoencephalitis were detected in all patients with a recurrence of cryptococcal meningitis under immune reconstitution, which differs from the classical magnetic resonance imaging findings in patients without antiretroviral therapy. In antiretroviral therapy-treated patients with past medical history of cryptococcal meningitis, detection of contrast-enhancing focal meningeal and/or parenchymal lesions should prompt further investigations for a recurrence of cryptococcal meningitis under immune reconstitution.

Cryptococcosis in HIV-infected hospitalized patients in Germany: Evidence for routine antigen testing

OBJECTIVES

To investigate the diagnostic value of routine cryptococcal antigen (CRAG) testing in HIV-infected patients in a low prevalence setting.

METHODS

Retrospective single centre cohort study of a 10-year period (2005-2014).

RESULTS

5461 patients tested for CRAG were included. Cryptococcal antigenaemia was found in 1.6% and 1.1% of patients with CD4 counts of ≤100/μl and 101-200/μl, respectively. The positive predictive values for identifying clinically relevant cryptococcal disease was 96% and 100%, respectively. Half of the patients had a non-specific presentation and median time-to-diagnosis was high (5 days, range 1-44 days). The median time-to-diagnosis in direct admissions to our centre with routine CRAG testing was significantly shorter: 1 day (range: 1-17) vs. 7 days (range: 2-44), p = 0.003. Prevalence of cryptococcal antigenaemia was 2.8% in patients with pneumocystis pneumonia and median time-to-diagnosis of cryptococcosis was significantly longer in this subgroup (15 days; range: 1-44 vs. 3 days; range: 1-17; p = 0.008). CRAG titres ≥1:512 were associated with disseminated disease (OR 21.3, p = 0.0008, 95% CI 1.64-277), however, 10% of patients with disseminated cryptococcosis had CRAG titres <1:16.

CONCLUSION

Our data support routine CRAG testing in hospitalized HIV-infected patients with CD4 counts ≤200/μl, and/or pneumocystis pneumonia.