Increasing incidence of cryptococcosis in the United Kingdom

Pulmonary cryptococcosis characteristics in immunocompetent patients-A 20-year clinical retrospective analysis in China

Background

Pulmonary cryptococcosis (PC) is not considered an rare, opportunistic infection anymore. The immunocompetent population accounts for an increasing proportion of the morbidity.

Objective

This study investigated the clinical characteristics of PC patients spanning 20 years, in a referral centre of China.

Patients/Methods

We retrospectively investigated the clinical data of 99 patients with PC who were diagnosed at Peking Union Medical College Hospital (PUMCH) from January 1998 to December 2017.

Results

Pulmonary cryptococcosis incidence in PUMCH has seen sharp increase in two decades. There were 40.4% (40/99), 17.2% (17/99) and 42.4% (42/99) immunocompetent, mildly immunocompromised and severe immunocompromised patients, respectively. Significantly higher (P = .035) male predominance in immunocompetent and mildly immunocompromised groups (68.4%, 39/57) compared with severe immunocompromised group (45.2%, 19/42) was found. Overall, 27.5% (11/40) immunocompetent patients reported a significant difference (P = .02) in history of more than weekly drinking, higher than mildly or severe immunocompromised. No significant difference occurred in symptoms and radiographic characteristics among the groups. In pulmonary computerised tomography findings, the non‐air pathway feature was the dominant distribution characteristics in all patients with PC (P = .002). The gap in body dissemination frequency between immunocompetent combined with mildly immunocompromised (5.26%, 3/57) and severe immunocompromised (19.0%, 8/42) was marginally significant (P = .05).

Conclusions

Gender and alcohol drinking could be PC risk factors of concern in patients without severe immunodeficiency. No significant difference occurred in symptoms or radiographic characteristics between patients with different levels of immune status. The unique radiographic non‐air pathway distribution in the lung may be the feature of Cryptococcus invasion that may enhance accurate diagnosis.

Cryptococcosis today: It is not all about HIV infection

Purpose of the review

Cryptococcal disease is most often thought of in the context of HIV infection. Much of our knowledge of the disease originates from its management in the HIV-positive population over the last 30 years. While the majority of cases globally continue to occur in the setting of advanced HIV, Cryptococcus species is increasingly responsible for disease in HIV-negative populations including those considered normal hosts and these HIV-negative populations will be the focus of this review.

Recent findings

Currently available data indicated that significant differences exist in epidemiology, clinical presentation, management and outcomes of cryptococcal disease in HIV-negative populations when compared to those living with HIV.

Summary

Further research is required to improve our knowledge of cryptococcal disease in particular in HIV-negative cohorts so as to optimise management of the disease in the future.

Cryptococcal meningitis: epidemiology and therapeutic options

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

New Insights into HIV/AIDS-Associated Cryptococcosis

Cryptococcal meningitis is a life-threatening opportunistic fungal infection in both HIV-infected and HIV-uninfected patients. According to the most recent taxonomy, the responsible fungus is classified into a complex that contains two species (Cryptococcus neoformans and C. gattii), with eight major molecular types. HIV infection is recognized worldwide as the main underlying disease responsible for the development of cryptococcal meningitis (accounting for 80-90% of cases). In several areas of sub-Saharan Africa with the highest HIV prevalence despite the recent expansion of antiretroviral (ARV) therapy programme, cryptococcal meningitis is the leading cause of community-acquired meningitis with a high mortality burden. Although cryptococcal meningitis should be considered a neglected disease, a large body of knowledge has been developed by several studies performed in recent years. This paper will focus especially on new clinical aspects such as immune reconstitution inflammatory syndrome, advances on management, and strategies for the prevention of clinical disease.

The Mediterranean red alga Asparagopsis: a source of compounds against Leishmania

Crude extracts and column fractions from the red algae Asparagopsis taxiformis and A. armata from the Strait of Messina (Italy) were screened for the production of antimicrobial compounds. Extracts from both species revealed remarkable antiprotozoal activity against Leishmania, revealing such algae as a great source of natural antiprotozoal products.

Disseminated cutaneous cryptococcosis in a patient with AIDS

The authors study a patient carrying AIDS, with exuberant dermatological manifestations of cryptococcosis. They stress the therapeutic effectiveness of short-term amphotericin B. The authors reviewed cases of cutaneous infection with Cryptococcus reported in the national and international literature, verifying that the frequency has increased with the AIDS epidemic. Also, they discuss about the differential diagnosis with some cases of dermatosis, particularly with the disseminated giant molluscum contagiosum. In relation to the therapy, they affirm that the choice of drug depends on the organ involved, as well as the immune state of the patient.

Inhibition of beta-1,3-glucan synthase and cell growth of Cryptococcus species by recombinant single-chain anti-idiotypic antibodies

Recombinant single-chain fragment variable (scFv) anti-idiotypic antibodies were produced to represent the internal image of a HM-1 killer toxin, which is characterized by a wide spectrum of anti-fungal activity through inhibiting beta-1,3-glucan synthase (GS). We examined if scFv antibodies are active against Cryptococcus species, a human pathogen of increasing medical importance. The anti-cryptococcal activity of scFv antibodies and HM-1 were assessed by MIC analysis for C. neoformans IFM 40215 and C. albidus NBRC 0612 cells. The scFv antibodies had strong anti-cryptococcal activity in vitro with IC50 at 1.07 x 10(-7) to 2.60 x 10(-7) M for C. neoformans and C. albidus. Furthermore, the scFv antibodies potentially inhibited GS of C. neoformans with IC50 at 1.27 x 10(-7) to 2.27 x 10(-7) M. Both the anti-fungal and anti-GS activities of the scFv antibodies were markedly neutralized by the monoclonal antibody that neutralizes HM-1 killer toxin.

Epidemiology of HIV-associated cryptococcosis in France (1985-2001): comparison of the pre- and post-HAART eras

OBJECTIVE

To analyse the epidemiological evolution of cryptococcosis in France after the introduction of highly active antiretroviral therapy (HAART).

DESIGN

Retrospective study of cryptococcosis cases recorded at the National Reference Center for Mycoses in France since 1985.

METHODS

Using the national surveillance data, we reviewed 1644 cases of HIV-associated cryptococcosis diagnosed in France (population, 59 million) between 1985 and 2001 and compared them to 335 cases recorded in HIV-negative patients.

RESULTS

The total number of cryptococcosis cases evolved in parallel to that recorded for HIV-infected patients. Changes occurring after HAART introduction were analysed. A negative binomial regression model established a 46% decrease of the incidence of cryptococcosis during the post-HAART era (1997-2001, n = 292) compared to the pre-HAART era (1985-1996, n = 1352). According to multivariate analysis, African origin, older age, heterosexual HIV contamination, no previous AIDS-defining illness, and no previous HIV infection diagnosis were variables independently associated with an increased risk of cryptococcosis during the post-HAART era. During the same period, the characteristics of the HIV-negative population did not change.

CONCLUSIONS

Our analysis of the national surveillance identified demographic factors associated with an increased risk of cryptococcosis in the post-HAART era suggesting that failure to consult and considering oneself not at risk were determinant in the current epidemiology of HIV-related cryptococcosis in France.

Microscopy and latex antigen negative cryptococcal meningitis

A HIV-positive patient presented with cryptococcal meningitis that was not detected by cerebrospinal fluid (CSF) latex antigen and direct microscopy. The diagnosis was confirmed by culture of the CSF and subsequent urine culture, both of which yielded an apparently acapsular strain of Cryptococcus neoformans. After 19 months the patient relapsed and capsulated yeasts were observed on this occasion on direct microscopy of the CSF. The latex antigen test was strongly positive. Culture again yielded an apparently acapsular isolate. Retrospective culture of all isolates obtained from this patient in sterile CSF resulted in the formation of capsules. This was confirmed by the requirement of normal non heat inactivated serum for neutrophil-cryptococcus attachment to occur in vitro. Although antigen and direct microscopy are frequently relied upon to diagnose cryptococcal meningitis, a negative result does not exclude the condition.

Cryptococcosis in Denmark: an analysis of 28 cases in 1988-1993

A total number of 31 events of systemic cryptococcal infection in 28 patients was identified in a nation-wide survey over 6 years from 1988 to the end of 1993. All medical records were reviewed, 24 of the patients were HIV-infected. Meningitis was diagnosed in 25 patients, and fungemia in 8 patients. The most frequent symptom was headache followed by fever. The median duration in days of fever, headache, and other neurological signs/symptoms before diagnosis was 12, 8 and 2 days, respectively, and, after diagnosis and start of treatments 7, 11 and 12 days, respectively. There was a significant correlation between the duration of headache and the duration of neurological signs/symptoms but not between headache and fever. More than 50% of the patients died within 5 months after the diagnosis. In 39% of the cases, the patients were orally treated with various antifungal drugs before the diagnosis. The rate of cryptococcosis (cumulative) in Danish AIDS patients was estimated to be 1.7%. The HIV-positive patients were, at the time of the cryptococcal diseases, profoundly immunocompromised, with a median CD4+ cell count of 18 (range: 0-78)/microliters. From 24 patients at least 1 isolate of Cryptococcus neoformans was typed, all being var. neoformans, identical with serotype A/D.

Cryptococcal infection in cats: factors influencing treatment outcome, and results of sequential serum antigen titers in 35 cats

The relationship between treatment outcome and location of cryptococcal infection, gender, magnitude of pretreatment cryptococcal antigen titers, results of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) serology, and serial changes in antigen titers during and after treatment were evaluated in a prospective and nonrandomized study of 35 cats with cryptococcosis. A commercial cryptococcal latex agglutination kit (CALAS; Meridian Diagnostic Inc, Cincinnati, OH) was used to detect cryptococcal antigen in sera. All cats were treated with itraconazole (Sporanox; Janssen Pharmaceutica Inc, Titusville, NJ). Pretreatment mean log titers for serum cryptococcal antigen were not influenced by location of the infection. Treatment outcome was not influenced by gender, location of the infection, or magnitude of pretreatment serum antigen titer. Treatment outcome was influenced by FeLV and FIV status; cats seropositive for FeLV or FIV had a higher likelihood of treatment failure (P = .008). The cryptococcal antigen titers of cats successfully treated decreased with significant linearity over time during treatment (r = -.64, P < .000001), whereas the corresponding titers for cats not treated successfully did not decrease with significant linearity (r = -.03, P > .9). For cats in which treatment was successful, antigen titers decreased significantly from pretreatment values by 1.3 orders of magnitude at 2 months after initiation of treatment. By 10 months after initiating treatment, log titers decreased by at least 2 orders of magnitude in all cats successfully treated, and 9 of 16 cats had undetectable titers. In contrast, in 5 of 6 cats in which treatment failed, antigen titers were unchanged or increased in magnitude even after at least 6 months of treatment.

Tumor necrosis factor-inducing activities of Cryptococcus neoformans components

Cryptococcus neoformans-induced tumor necrosis factor alpha (TNF-alpha) production may lead to increased human immunodeficiency virus replication in patients with AIDS. In order to identify cryptococcal components that are predominantly responsible for stimulating TNF production, various concentrations of glucuronoxylomannan (GXM), galactoxylomannan (GalXM), mannoproteins (MP), and alpha(1-3) [corrected] glucan were added to whole-blood cultures. All of the cryptococcal components tested, as well as whole heat-killed cryptococci, were capable of inducing TNF-alpha release in a dose-dependent manner. MP were significantly more potent than any of the other cryptococcal components tested or heat-killed cryptococci in stimulating TNF-alpha production (P < 0.05). GXM, in contrast, was significantly less potent in this activity than either GalXM or MP (P < 0.05). As little as 0.5 microg of MP per ml was sufficient to produce moderate but significant elevations of TNF-alpha release. Maximal MP-induced TNF-alpha levels were similar to those induced by Salmonella enteritidis lipopolysaccharide, our positive control. Further experiments using isolated leukocytes suggested that monocytes were the cell population mainly responsible for TNF-alpha production, although the participation of other cell types could not be excluded. The presence of complement-sufficient plasma was a necessary requirement for TNF-alpha induction by GXM, GalXM, and low doses of MP. High MP concentrations (100 microg/ml) were also capable of stimulating TNF-alpha production in the absence of plasma. These data indicate that soluble products released by C. neoformans are capable of inducing TNF-alpha secretion in human leukocytes. This may be clinically relevant, since high concentrations of such products are frequently found in the body fluids of AIDS patients infected with C. neoformans.

A vitamin-free minimal synthetic medium for Cryptococcus neoformans

The use of a simple synthetic medium is essential for study on the growth and physiology of Cryptococcus neoformans. In the present study, a minimal synthetic liquid medium (MSM) was tested for the growth of 23 C. neoformans strains. This medium contained a low concentration of glucose, ammonium sulphate and inorganic salts with a pH value of 4.5, but no amino acids or vitamins. The strains were starved for 4 days to eliminate nutrients which might have been carried over from their pre-culture medium. Then, they were inoculated in the MSM as an initial OD of 0.020 at 550 nm and incubated at 37 degrees C for 20 days. Cell growth was generally monitored daily by measuring the absorbance at 550 nm. The medium supported the growth of the strains tested and gave an average final OD of 0.500. The results obtained indicate that C. neoformans may be autotrophic with respect to vitamins and in particular to thiamine. The MSM medium is easy to prepare and store. It is highly reproducible and useful for studies on the growth and physiology of C. neoformans.

Cryptococcosis associated with HIV negative Indian patients and HIV positive Indian blood donors

Cryptococcosis, particularly cryptococcal meningitis (CM), has become an increasing problem globally in the AIDS era. In the present investigation we have made an effort for the first time to study Indian cases (100) both HIV-positive (23 cases, male, mostly Indian professional blood donors, PBDs') confirmed by an ELISA test and Western Blot but asymptomatic for CM and HIV-negative (77:49 male and 28 female) asymptomatic or symptomatic. These subjects were patients from the Lucknow hospitals admitted during the period between February, 1991 to February, 1994, for suspected cryptococcosis or CM. Of those cases, 10% were positive for cryptococcosis or CM. Meningoencephalitis was the dominant clinical manifestation in four (HIV-negative) cases of CM. CT scanning of the head of those cases revealed a noncommunicating hydrocephalus due to aqueductal stenosis (in 2 cases) and a communicating hydrocephalus with granuloma (by MRI) in another case. The latex agglutination test (LAT) of the sera was positive for Cryptococcus antigen in 6 (26%) of the (HIV-positive) patients and 4 (5%), of the HIV-negative cases. In the cases of CM, there was a lower antigen titre in CSF than in the pronase-treated sera. The LAT was found to be useful in diagnosis of cryptococcosis, especially in asymptomatic cases. The CSF of CM-positive cases revealed low levels of glucose, reduced cell count and high proteins. Among the HIV-negative cases, the onset of meningitis in 4 cases was preceded by the presence of encapsulated budding yeast cells in CSF India ink smear, or cryptococci in a direct urine smear in one case. The CSF culture of 3 cases was positive for mucoid Cryptococcus neoformans, showing brown colour effect (BCE) on Staib agar (syn. Guizotia abyssinica creatinine agar, bird seed agar). The isolated yeast strains were identified as C. neoformans var. neoformans by physiological tests. The pathogenicity test of strains revealed virulence to BALB/c mice evidenced by a high mortality of mice and significantly (p < 0.05) high CN burden (> 4-5 mean log(10) cfu), in the brain followed by other visceral organs (lung, liver, spleen, kidney and heart). The in-vitro susceptibility (MIC mu gmL(-1)) of strains.

Binding of host collectins to the pathogenic yeast Cryptococcus neoformans: human surfactant protein D acts as an agglutinin for acapsular yeast cells

Cryptococcus neoformans is an opportunistic pathogen in AIDS patients causing disseminated disease and lethal meningitis after inhalation of acapsular or sparsely encapsulated yeast cells. In this study we have investigated whether a recently described family of primitive opsonins, termed collectins, contribute to innate resistance against C. neoformans. The pulmonary surfactant proteins SP-A and SP-D as well as the serum collectins mannose-binding protein and CL-43 bound in a calcium-dependent manner to acapsular C. neoformans in vitro. Binding was concentration dependent and abolished by competition with defined mono- and oligosaccharides. In contrast, no binding of the collectins was observed with the encapsulated form of the yeast. Furthermore, binding of purified collectin SP-D, but not SP-A, mannose-binding protein, or CL-43, led to a concentration-dependent agglutination of acapsular C. neoformans. These data indicate that collectins recognize carbohydrate structures in the cell wall of an initial infectious form of C. neoformans and may play a role in early antifungal defenses in the lung.