Outcomes of central nervous system cryptococcosis vary with host immune function: Results from a multi-center, prospective study

Optical coherence tomography findings of macula and neural changes in cryptococcal meningitis

PURPOSE

To investigate the structures and neural changes in cryptococcal meningitis (CM) patients compared with healthy controls.

DESIGN

Retrospective, cross-sectional, cohort study.

METHODS

Seventy-six eyes of 39 CM patients were included in this observational clinical cohort study. Thirty eyes of 16 CM patients with papilledema were included in Group 1, and 46 eyes of 23 CM patients without papilledema were included in Group 2. Another 80 eyes of 40 healthy participants were included in Group 3 as controls. Optical coherence tomography (OCT) images were obtained from all the participants via a DRI OCT Triton 3D device with its prototype IMAGEnet 6 for OCT software.

RESULTS

Compared with those of the controls, the peripapillary retinal nerve fiber layer thickness (pRNFLT), peripapillary GCL++ thickness [pGCL++T, including the RNFL, ganglion cell layer (GCL), and inner plexiform layer (IPL)], peripapillary GCL+ thickness (pGCL+T, including the RNFL and IPL) and peripapillary choroidal thickness (pCT) were dramatically increased in CM patients with papilledema but decreased in those from CM patients with no papilledema. There was a similar trend in macular GCL++ thickness (mGCL++T) and macular GCL+ thickness (mGCL+T) in CM absent from optic swelling when compared with healthy controls.

CONCLUSION

Papilledema may or may not be present depending on the timing of the evaluation, and the ophthalmologic manifestations of CM with papilledema can be well observed. However, changes in the optic nerve head (ONH) and peripapillary structures in CM patients with no papilledema can be detected by optical coherence tomography. Parameters such as pRNFLT, pGCL++T, pGCL+T and pCT may provide useful evidence for the early detection of structures and neural impairments in patients with CM.

Cerebrospinal Fluid Lactate Levels as a Prognostic Indicator in Patients With Cryptococcal Meningitis Who Are HIV Negative: A Retrospective Cohort Study

Background

Cryptococcal meningitis (CM) is a severe central nervous system infection. In patients with HIV infections and coexisting CM, elevated baseline cerebrospinal fluid (CSF) lactate levels can predict increased mortality. However, the CSF lactate level's significance in patients with CM who are HIV negative remains unclear, necessitating further investigation to elucidate the potential distinctions and enhance patient management. This study investigated the significance of CSF lactate levels in patients with CM who were HIV negative.

Methods

This retrospective study utilized data from the clinical databases of patients who underwent lumbar punctures at a medical center in Kaohsiung City, southern Taiwan. Demographic data, CSF lactate levels, routine CSF analyses, and hematologic and neurologic findings were evaluated. The optimal CSF lactate threshold value was determined by the Youden index.

Results

This retrospective study included 70 patients with CM, among whom 44 (63%) and 26 (37%) tested negative and positive for HIV, respectively. The group without HIV exhibited higher CSF lactate levels, with an optimal CSF lactate cutoff point of 7.935 mmol/L for predicting 90-day mortality, resulting in significant predictive accuracies (area under the curve, 0.755; sensitivity, 57.1%; specificity, 100%); this value was an independent mortality predictor in patients who were HIV negative. In patients with CM who were HIV negative, CSF lactate levels ≥7.935 mmol/L correlated with higher mortality rates but without statistical significance. All patients with CM who were HIV negative and had CSF lactate levels ≥7.935 mmol/L died within 3 months of admission.

Conclusions

Patients with CM who were HIV negative had elevated CSF lactate levels that correlated with adverse outcomes, enabling early identification of high-risk individuals.

Human T-Lymphotropic Virus Type 1 and Cryptococcosis Infection, an Underdiagnosed Association: Case Series and Literature Review

Clinical and epidemiological features of 7 human immunodeficiency virus-negative Peruvian patients coinfected with human T-lymphotropic virus type 1 (HTLV-1) and cryptococcosis (2006-2017) were studied. Most cases had meningeal involvement, were male, and originated from Peru's jungle. Patients with cryptococcosis should be tested for HTLV-1 in endemic areas of this retrovirus.

Pulmonary cryptococcosis complicated with pulmonary aspergillosis: a series of studies and a literature review

BACKGROUND/OBJECTIVE

With the development of society, pulmonary fungal diseases, represented by pulmonary aspergillosis and pulmonary cryptococcosis, have become increasingly common. However, there is a lack of clear understanding regarding coinfection by these two types of fungi in immunocompetent individuals.

METHODS

A retrospective study from 2014 to 2022 and a systematic literature review of original articles published in English were performed. Patients with pulmonary cryptococcosis complicated with pulmonary aspergillosis including 5 in the retrospective study and 6 in the systematic literature review.

RESULT

The diagnosis of concurrent pulmonary cryptococcosis and pulmonary aspergillosis in patients was confirmed through repeated biopsies or surgical resection. Pulmonary cryptococcosis is often diagnosed initially (6/11, 55%), while the diagnosis of pulmonary aspergillosis is established when the lesions become fixed or enlarged during treatment. Transbronchial lung biopsy (3/11, 27%), thoracoscopic lung biopsy (2/11, 18%), and percutaneous aspiration biopsy of the lung (1/11, 9%) were the main methods to confirm concurrent infection. Most patients were treated with voriconazole, resulting in a cure for the coinfection (6/11, 55%).

CONCLUSION

Pulmonary cryptococcosis complicated with pulmonary Aspergillus is an easily neglected mixed fungal infection. During the treatment of lesion enlargement in clinical cryptococcus, we need to watch out for Aspergillus infection.

The prognostic factors for cryptococcal meningitis in non-human immunodeficiency virus patients: An observational study using nationwide database

BACKGROUND

Cryptococcal meningitis (CM) is an invasive fungal infection with a poor prognosis that often occurs in both healthy individuals and compromised hosts, such as patients infected with human immunodeficiency virus (HIV). Unlike CM in HIV patients, evidence regarding CM in non-HIV patients is limited to small retrospective studies.

OBJECTIVE

To identify the pretreatment prognostic factors for CM in non-HIV patients.

METHODS

We conducted a large retrospective analysis of CM in non-HIV patients using data from a nationwide Japanese database. The study included hospitalized patients diagnosed with CM between 1 April 2010 and 31 March 2017. All-cause mortality was compared between patients with CM with and without HIV infection. Poor diagnostic factors were analysed in the non-HIV CM group.

RESULTS

Overall, 533 (64 HIV and 469 non-HIV) patients met the criteria. The mortality rate at 90 days was significantly lower in the HIV group (6.3% vs. 25.4% p = .0002). In a logistic regression analysis of the non-HIV group, age ≥ 65 y (odds ratio [OR] 2.37, 95% CI 1.17-4.78), impaired consciousness (Japan Coma Scale ≥1) (OR 2.25, 95% CI 1.29-3.93), haemodialysis (OR 3.53, 95% CI 1.12-11.20) and previous corticosteroid usage (OR 2.40, 95% CI 1.37-4.19) were associated with poor prognosis at 30 days after diagnosis.

CONCLUSION

More caution is suggested when treating non-HIV with CM in older patients with impaired consciousness, previous corticosteroid usage and haemodialysis.

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

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

Ocular Findings of Cryptococcal Meningitis in Previously Healthy Adults

BACKGROUND

Patients with cryptococcal meningitis (CM) often have ocular manifestations; although data are describing these findings in nonimmunosuppressed, previously healthy individuals are scarce.

METHODS

A retrospective chart review was performed for previously healthy patients with CM who underwent a complete ophthalmological examination within a 5-year period at the National Institutes of Health. Demographics, CSF parameters, findings on initial ophthalmological examination, and MRI abnormalities were analyzed.

RESULTS

Forty-four patients within a median of 12 weeks after CM diagnosis were included in our study; 27 patients (61%) reported abnormal vision on presentation. Seventy-one percent of patients were not shunted at the time of their initial eye examination. The most common ocular abnormalities were visual field defects in 21 (66%), decreased visual acuity in 14 (38%), and papilledema in 8 (26%) patients. Intraocular pressure was within normal range in all patients. Cranial nerve defects were identified in 5 patients and optic neuropathy in 2 patients. Patients who had hydrocephalus or did not receive a ventriculoperitoneal shunt were not noted to have worse ocular abnormalities.

CONCLUSIONS

The most common ocular findings in our cohort of nontransplant, non-HIV cryptococcal meningitis patients were visual field defects, decreased visual acuity, and papilledema. Our results emphasize the need for a comprehensive eye examination in patients with CM who may not always report a change in vision on presentation.

Neuroimaging of Cryptococcal Meningitis in Patients without Human Immunodeficiency Virus: Data from a Multi-Center Cohort Study

BACKGROUND

A clearer understanding is needed about the use of brain MRI in non-HIV patients with cryptococcal meningitis.

METHODS

Cerebral CT and MRI were studied in 62 patients in a multicenter study of cryptococcal meningitis in non-HIV patients. CT was performed in 51 and MRI in 44. MRI results are reported for the images read at NIH for 29 of the 44 patients. CT reports obtained from the original REDCap database were added to calculate the incidence of normal findings.

RESULTS

CTs were read as normal in 24 of 51 (47%), MRIs were normal in 10% (three of 29). The most characteristic lesions of cryptococcal meningitis on MRI were small basal ganglia lesions representing dilated perivascular spaces in 24% and basal ganglia lesions with restricted diffusion (infarcts) in 38%. In the 18 patients who received contrast, contrast-enhancing lesions, likely representing masses of cryptococci and inflammatory cells, were found in the basal ganglia in 22% and elsewhere in the brain in 22%. Meningeal enhancement was seen in 56%, ependymal enhancement in 24%, and choroid plexus enhancement in 11%. Hydrocephalus was found in five (18%), though increased intacranial pressure was not detected. Suboptimal imaging (n = 6), lack of contrast administration (n = 11) and lack of follow-up, however, markedly limited the accurate assessment of abnormalities in multiple cases.

CONCLUSION

MRI characteristics of non-HIV cryptococcal meningitis include hydrocephalus, meningeal and ependymal enhancement and basal ganglia lesions. Optimal imaging is, however, necessary to maximize the diagnostic and prognostic usefulness of MRI.

Cerebral cryptococcoma successfully treated by isavuconazole in an immunocompetent patient: A case report

Cryptococcosis has been recognized as an increasing cause of severe systemic mycosis in immunocompetent patients in the last few years. Cerebral cryptococcomas are a more uncommon manifestation of cryptococcal meningitis, which are not usually included in the differential of brain masses. We report a case of a young, immunocompetent woman that rapidly developed severe neurological deficits. She was ultimately diagnosed with cerebral cryptococcoma caused by both Cryptococcus neoformans and Cryptococcus gattii, and was treated with amphotericin B and isavuconazole. After several complications during hospitalization, including hydrocephalus and cerebellitis, she was discharged home on isavuconazole. On follow-up, she only complained of anosmia. We review the clinical and radiological findings of similar cases. It is the first time that this form of cryptococcal meningitis is favorably treated with isavuconazole and is caused by 2 species of Cryptococcus. We emphasize that cerebral cryptococcomas should be suspected in immunocompetent patients that present with brain masses.

Cryptococcal Meningitis in an Immunocompetent Man Exposed to a Pet Cockatoo: An Overlooked Zoonosis

Cryptococcus species are commonly isolated in the excreta of birds, but zoonotic transmission has yet to be proven. We report a case of an immunocompetent man with meningitis caused by Cryptococcus neoformans var. grubii with significant exposure to a pet cockatoo highly suspicious for zoonotic transmission. Treatment with intravenous liposomal amphotericin B and oral flucytosine was initiated upon diagnosis, but diagnostic delay because of low suspicion contributed to neurological sequelae. Recognition of pet birds as potential sources of Cryptococcus species' zoonotic transmission is essential for prompt diagnosis and treatment.

Disseminated Cryptococcal Disease in a Patient With Monoclonal Gammopathy of Undetermined Significance and Polycythemia Vera: A Case Report and Review of the Literature

Cryptococcosis is a life-threatening opportunistic infection caused by Cryptococcus gattii and Cryptococcus neoformans. It affects both immunocompetent and immunosuppressed hosts. Disseminated cryptococcal infection is rare in immunocompetent patients, but the cryptococcal disease's neurological sequelae may be more prominent in this group. We present a case of a 58-year-old male patient with medical comorbidities of monoclonal gammopathy of undetermined significance (MGUS) and polycythemia vera. The patient presented with gradual worsening of mental status over one week. He was found to have Cryptococcus neoformans meningoencephalitis and fungemia. The patient received two weeks of liposomal amphotericin B (LAmB) and flucytosine with excellent clinical response. He was discharged on high dose fluconazole, and he returned to the hospital in one week with new-onset hemiplegia and cryptococcomas on imaging. Prolonged intravenous (IV) treatment of six weeks duration resulted in significant clinical improvement and disease-free state at two years follow-up. This article aims to stress the importance of individualized prolonged IV treatment with liposomal amphotericin B and flucytosine despite good initial response in patients with polycythemia vera and MGUS. This is the first reported case of cryptococcal disease, to the best of our knowledge, in a patient with MGUS and the third case of cryptococcal infection in patients with polycythemia vera in a non-HIV non-transplant state. Prolonged individualized IV treatment should be considered in immunocompetent patients with the above conditions, as this condition, if not adequately treated and relapses, lead to high morbidity and mortality.

Increased cryptococcal meningitis mortality among HIV negative, non-transplant patients: a single US center cohort study

Cryptococcal meningitis (CM) is an opportunistic fungal infection associated with human immunodeficiency virus (HIV) and other forms of immunosuppression. We lack a clear understanding of CM associated mortality among HIV-negative, non-transplant patients in the United States (US). This article compares clinical features and outcomes across HIV status in patients with laboratory-confirmed CM.

Methods

A retrospective cohort study was performed that included adult patients with laboratory-confirmed CM treated at an academic tertiary hospital between January 2000 and September 2018. Those with a history of organ transplant or non-meningeal infections were excluded. Data were gathered on demographics, HIV status, clinical presentation, cerebrospinal fluid (CSF) profiles, neurological outcomes, hospital course, and mortality.

Results

A total of 70 patients with cryptococcal disease were identified. Our final sample included 36 CM patients, mean age was 48.8 ± 13.2 years; of this group, 66.7% (n = 24) had HIV. Median [interquartile range (IQR)] absolute CD4 count for the HIV group was 35 cells/μl (10-80 cells/μl). Non-HIV/non-transplant patients were significantly older (p < 0.001) and had higher rates of altered mental status (AMS) on presentation (58.3% versus 25%, p = 0.05). Non-HIV patients/non-transplant patients had significantly higher CSF white blood cell (WBC) count (p = 0.02), lower CSF glucose (p = 0.005), and higher CSF protein (p < 0.001) compared with HIV patients. There was no significant variation in temperature, blood pressure, WBC count, serum sodium, CSF opening pressure, length of stay, intensive care unit admission, or neurological outcomes. Overall, 90-day all-cause mortality was 19.4%: mortality rates were significantly higher in non-HIV/non-transplant patients at both 90 days (41.7% versus 8.3%, p = 0.017) and 1 year (41.7% versus 12.5%, p = 0.047).

Conclusion

Compared with HIV-infected individuals, non-HIV/non-transplant CM patients have a higher CSF WBC count at the time of diagnosis, higher rates of AMS on presentation, and higher rates of 90-day and 1-year all-cause mortality. Further prospective research is needed to identify the hallmarks of CM in non-HIV/non-transplant patients to facilitate early identification and intervention.

The Added Value of Longitudinal Imaging for Preclinical In Vivo Efficacy Testing of Therapeutic Compounds against Cerebral Cryptococcosis

Brain infections with Cryptococcus neoformans are associated with significant morbidity and mortality. Cryptococcosis typically presents as meningoencephalitis or fungal mass lesions called cryptococcomas. Despite frequent in vitro discoveries of promising novel antifungals, the clinical need for drugs that can more efficiently treat these brain infections remains. A crucial step in drug development is the evaluation of in vivo drug efficacy in animal models. This mainly relies on survival studies or postmortem analyses in large groups of animals, but these techniques only provide information on specific organs of interest at predefined time points. In this proof-of-concept study, we validated the use of noninvasive preclinical imaging to obtain longitudinal information on the therapeutic efficacy of amphotericin B or fluconazole monotherapy in meningoencephalitis and cryptococcoma mouse models. Bioluminescence imaging enabled the rapid in vitro and in vivo evaluation of drug efficacy, while complementary high-resolution anatomical information obtained by magnetic resonance imaging of the brain allowed a precise assessment of the extent of infection and lesion growth rates. We demonstrated a good correlation between both imaging readouts and the fungal burden in various organs. Moreover, we identified potential pitfalls associated with the interpretation of therapeutic efficacy based solely on postmortem studies, demonstrating the added value of this noninvasive dual imaging approach compared to standard mortality curves or fungal load endpoints. This novel preclinical imaging platform provides insights in the dynamic aspects of the therapeutic response and facilitates a more efficient and accurate translation of promising antifungal compounds from bench to bedside.

AIDS-associated Talaromyces marneffei central nervous system infection in patients of southwestern China

Background

The clinical and laboratory characteristics of AIDS-associated Talaromyces marneffei infection, a rare but a fatal mycosis disease of the central nervous system, remain unclear.

Case presentation

Herein, we conducted a retrospective study of ten AIDS patients with cerebrospinal fluid culture-confirmed central nervous system infection caused by Talaromyces marneffei. All 10 patients were promptly treated with antifungal treatment for a prolonged duration and early antiviral therapy (ART). Among them, seven patients were farmers. Nine patients were discharged after full recovery, while one patient died during hospitalization, resulting in a mortality rate of 10%. All patients initially presented symptoms and signs of an increase in intracranial pressure, mainly manifesting as headache, dizziness, vomiting, fever, decreased muscle strength, diplopia or even altered consciousness with seizures in severe patients. Nine patients (90%) showed lateral ventricle dilatation or intracranial infectious lesions on brain CT. Cerebrospinal fluid findings included elevated intracranial pressure, increased leukocyte count, low glucose, low chloride and high cerebrospinal fluid protein. The median CD4⁺ T count of patients was 104 cells/μL (IQR, 36–224 cells/μL) at the onset of the disease. The CD4⁺ T cell counts of three patients who eventually died were significantly lower (W = 6.00, p = 0.020) than those of the patients who survived.

Conclusions

The common clinical symptoms of T. marneffei central nervous system infection are associated with high intracranial pressure and intracranial infectious lesions. Earlier recognition and diagnosis and a prolonged course of amphotericin B treatment followed by itraconazole combined with early ART might reduce the mortality rate.

Drug Repurposing of Haloperidol: Discovery of New Benzocyclane Derivatives as Potent Antifungal Agents against Cryptococcosis and Candidiasis

Despite the high morbidity and mortality of invasive fungal infections (IFIs), effective and safe antifungal agents are rather limited. Starting from antifungal lead compound haloperidol that was identified by drug repurposing, a series of novel benzocyclane derivatives were designed, synthesized, and assayed. Several compounds showed improved antifungal potency and broader antifungal spectra. Particularly, compound B10 showed good inhibitory activities against a variety of fungal pathogens and was proven to be an inhibitor of several virulence factors important for drug resistance. In the in vivo cryptococcosis and candidiasis models, compound B10 could effectively reduce the brain fungal burden of Cryptococcus neoformans and synergize with fluconazole to treat resistant Candida albicans infections. Preliminary antifungal mechanism studies revealed that compound B10 regained cell membrane damage and down-regulated the overexpression of ERG11 and MDR1 genes when used in combination with fluconazole. Taken together, haloperidol derivative B10 represents a promising lead compound for the development of a new generation of antifungal agents.

Ventriculoperitoneal shunt insertion in human immunodeficiency virus infected adults: a systematic review and meta-analysis

BACKGROUND

Hydrocephalus is a common, life threatening complication of human immunodeficiency virus (HIV)-related central nervous system opportunistic infection which can be treated by insertion of a ventriculoperitoneal shunt (VPS). In HIV-infected patients there is concern that VPS might be associated with unacceptably high mortality. To identify prognostic indicators, we aimed to compare survival and clinical outcome following VPS placement between all studied causes of hydrocephalus in HIV infected patients.

METHODS

The following electronic databases were searched: The Cochrane Central Register of Controlled Trials, MEDLINE (PubMed), EMBASE, CINAHL Plus, LILACS, Research Registry, the metaRegister of Controlled Trials, ClinicalTrials.gov, African Journals Online, and the OpenGrey database. We included observational studies of HIV-infected patients treated with VPS which reported of survival or clinical outcome. Data was extracted using standardised proformas. Risk of bias was assessed using validated domain-based tools.

RESULTS

Seven Hunderd twenty-three unique study records were screened. Nine observational studies were included. Three included a total of 75 patients with tuberculous meningitis (TBM) and six included a total of 49 patients with cryptococcal meningitis (CM). All of the CM and two of the TBM studies were of weak quality. One of the TBM studies was of moderate quality. One-month mortality ranged from 62.5-100% for CM and 33.3-61.9% for TBM. These pooled data were of low to very-low quality and was inadequate to support meta-analysis between aetiologies. Pooling of results from two studies with a total of 77 participants indicated that HIV-infected patients with TBM had higher risk of one-month mortality compared with HIV non-infected controls (odds ratio 3.03; 95% confidence-interval 1.13-8.12; p = 0.03).

CONCLUSIONS

The evidence base is currently inadequate to inform prognostication in VPS insertion in HIV-infected patients. A population-based prospective cohort study is required to address this, in the first instance.

Clinical Aspects of Immune Damage in Cryptococcosis

Purpose of review

To perform an extensive review of recent literature and provide an update on the current epidemiology, clinical features and management of cryptococcal disease with a focus on the differences between patients depending on their immune status.

Recent findings

Emerging literature has highlighted the inflammatory pathophysiology and varied manifestations of cryptococcal infections in patients who are apparently healthy but paradoxically have a more critical clinical course compared to their immunosuppressed counterparts.

Summary

Non-HIV cryptococcal meningitis has greater mortality compared to that seen in HIV patients. Basic science experiments closely analyzing the underlying pathophysiological response to this infection have demonstrated the predominant role of T cell-mediated inflammatory injury in causing worse clinical outcomes. Further studies are needed to define the need for immunosuppressive agents in the treatment of this illness.

Infection in Kidney Transplant Recipients

In organ transplant recipients, impaired inflammatory responses suppress the clinical and radiologic findings of infection. The possible etiologies of infection are diverse, ranging from common bacterial and viral pathogens that affect the entire community to opportunistic pathogens that cause invasive disease only in immunocompromised hosts. Antimicrobial therapies required to treat established infection are often complex, with accompanying risks for drug toxicities and drug interactions with the immunosuppressive agents used to maintain graft function. Rapid and specific diagnosis is essential for successful therapy. The risk of serious infections in the organ transplant patient is largely determined by the interaction between two factors: the patient’s epidemiologic exposures and the patient’s net state of immunosuppression. The epidemiology of infection includes environmental exposures and nosocomial infections, organisms derived from donor tissues, and latent infections from the recipient activated with immunosuppression. The net state of immune suppression is a conceptual framework that measures those factors contributing to risk for infection: the dose, duration, and temporal sequence of immunosuppressive drugs; the presence of foreign bodies or injuries to mucocutaneous barriers; neutropenia; metabolic abnormalities including diabetes; devitalized tissues, hematomas, or effusions postsurgery; and infection with immunomodulating viruses. Multiple factors are present in each host. A timeline exists to aid in the development of a differential diagnosis for infection. The timeline for each patient is altered by changes in prophylaxis and immunosuppressive drugs. For common infections, new microbiologic assays, often nucleic acid based, are useful in the diagnosis and management of opportunistic infections.

High dose fluconazole in salvage therapy for HIV-uninfected cryptococcal meningitis

Background

The 2010 Infectious Diseases Society of America (IDSA) guidelines for management of cryptococcal diseases recommend high dose fluconazole (≥ 800 mg/day), either alone or with other antifungal drugs, as alternative anticryptococcal choices. But evidence for its use in the treatment of HIV-uninfected cryptococcal meningitis (CM) remains sparse.

Methods

A retrospective analysis of HIV-uninfected CM patients who received fluconazole 800 mg/day for salvage therapy from January 2011 to December 2016 at Huashan Hospital, Shanghai, China was performed. Efficacy and safety were assessed, and mortality and prognostic factors evaluated.

Results

A total of 44 patients were studied including 19 refractory to amphotericin B induction therapy, 8 refractory to fluconazole consolidation therapy (400 mg/d), and 17 intolerant of antifungal drugs. For salvage, 11 patients received triple therapy of high dose fluconazole, amphotericin B and flucytosine, 20 received dual therapy of high dose fluconazole and flucytosine, 13 received monotherapy of high dose fluconazole. Median duration of high dose fluconazole in salvage regimens was 136.5 days (range, 1–667 days). Clinical response rates were 72.1% (31/43) and 83.7% (36/43) when assessed at 2 weeks and the end of salvage therapy, respectively. Adverse events possibly related to high dose fluconazole occurred in 54.5% (24/44) of the patients, and all were mild or moderate. From the initiation of salvage therapy, 1-year all-cause mortality was 13.6% (6 of 44 patients) among the study population with no significant difference in refractory or intolerant patients.

Conclusions

Adherence to guideline recommendations of high dose fluconazole, alone or in combination with other antifungals, was safe and often effective for salvage therapy of HIV-uninfected CM patients.

Neuroinfections caused by fungi

BACKGROUND

Fungal infections of the central nervous system (FIs-CNS) have become significantly more common over the past 2 decades. Invasion of the CNS largely depends on the immune status of the host and the virulence of the fungal strain. Infections with fungi cause a significant morbidity in immunocompromised hosts, and the involvement of the CNS may lead to fatal consequences.

METHODS

One hundred and thirty-five articles on fungal neuroinfection in PubMed, Google Scholar, and Cochrane databases were selected for review using the following search words: "fungi and CNS mycoses", CNS fungal infections", "fungal brain infections", " fungal cerebritis", fungal meningitis", "diagnostics of fungal infections", and "treatment of CNS fungal infections". All were published in English with the majority in the period 2000-2018. This review focuses on the current knowledge of the epidemiology, clinical presentations, diagnosis, and treatment of selected FIs-CNS.

RESULTS

The FIs-CNS can have various clinical presentations, mainly meningitis, encephalitis, hydrocephalus, cerebral abscesses, and stroke syndromes. The etiologic factors of neuroinfections are yeasts (Cryptococcus neoformans, Candida spp., Trichosporon spp.), moniliaceous moulds (Aspergillus spp., Fusarium spp.), Mucoromycetes (Mucor spp., Rhizopus spp.), dimorphic fungi (Blastomyces dermatitidis, Coccidioides spp., Histoplasma capsulatum), and dematiaceous fungi (Cladophialophora bantiana, Exophiala dermatitidis). Their common route of transmission is inhalation or inoculation from trauma or surgery, with subsequent hematogenous or contiguous spread. As the manifestations of FIs-CNS are often non-specific, their diagnosis is very difficult. A fast identification of the etiological factor of neuroinfection and the application of appropriate therapy are crucial in preventing an often fatal outcome. The choice of effective drug depends on its extent of CNS penetration and spectrum of activity. Pharmaceutical formulations of amphotericin B (AmB) (among others, deoxycholate-AmBd and liposomal L-AmB) have relatively limited distribution in the cerebrospinal fluid (CSF); however, their detectable therapeutic concentrations in the CNS makes them recommended drugs for the treatment of cryptococcal meningoencephalitis (AmBd with flucytosine) and CNS candidiasis (L-AmB) and mucormycosis (L-AmB). Voriconazole, a moderately lipophilic molecule with good CNS penetration, is recommended in the first-line therapy of CNS aspergillosis. Other triazoles, such as posaconazole and itraconazole, with negligible concentrations in the CSF are not considered effective drugs for therapy of CNS fungal neuroinfections. In contrast, clinical data have shown that a novel triazole, isavuconazole, achieved considerable efficacy for the treatment of some fungal neuroinfections. Echinocandins with relatively low or undetectable concentrations in the CSF do not play meaningful role in the treatment of FIs-CNS.

CONCLUSION

Although the number of fungal species causing CNS mycosis is increasing, only some possess well-defined treatment standards (e.g., cryptococcal meningitis and CNS aspergillosis). The early diagnosis of fungal infection, accompanied by identification of the etiological factor, is needed to allow the selection of effective therapy in patients with FIs-CNS and limit their high mortality.

Quantifying donor-to-donor variation in macrophage responses to the human fungal pathogen Cryptococcus neoformans

Cryptococcosis remains the leading cause of fungal meningitis worldwide, caused primarily by the pathogen Cryptococcus neoformans. Symptomatic cryptococcal infections typically affect immunocompromised patients. However, environmental exposure to cryptococcal spores is ubiquitous and most healthy individuals are thought to harbor infections from early childhood onwards that are either resolved, or become latent. Since macrophages are a key host cell for cryptococcal infection, we sought to quantify the extent of individual variation in this early phagocyte response within a small cohort of healthy volunteers with no reported immunocompromising conditions. We show that rates of both intracellular fungal proliferation and non-lytic expulsion (vomocytosis) are remarkably variable between individuals. However, we demonstrate that neither gender, in vitro host inflammatory cytokine profiles, nor polymorphisms in several key immune genes are responsible for this variation. Thus the data we present serve to quantify the natural variation in macrophage responses to this important human pathogen and will hopefully provide a useful "benchmark" for the research community.

Clinical features of pulmonary cryptococcosis among patients with different levels of peripheral blood CD4+ T lymphocyte counts

Background

The clinical manifestation of pulmonary cryptococcosis varies notably between immunocompromised and immunocompetent patients. To better understand pulmonary cryptococcosis, we compared the clinical features of pulmonary cryptococcosis patients with or without decreased peripheral blood CD4⁺ T cell counts.

Methods

We retrospectively reviewed the medical records of 80 patients with cryptococcosis who had been treated in Jingling Hospital from January 2011 to January 2016. According to the normal range of peripheral blood CD4 + T-lymphocyte counts in our population, we chose CD4 = 378/μL as a cut-off value.

Results

The proportion of fever in the patients with decreased CD4+ T cells was higher than that of the patients with a normal amount of CD4+ T cells (86.7% vs 28.6%, P < 0.001). The incidence of clinical symptoms, such as cough (60.6% vs 64.7%, P = 0.729), chest pain (9.1% vs 26.5%, P = 0.064), and dyspnea (27.3% vs 23.5%, P = 0.725) showed no difference between patients with low CD4⁺ T cell counts and those with normal CD4+ T cell counts. The number of asymptomatic patients in the CD4⁺ T cell normal group was higher than that in the decreased CD4⁺ T cell group (17.1% vs 0%, P = 0.005). Nodules, masses, and halo signs were more common in the CD4⁺ T cell normal patients than in the low-CD4+ T cell patients (79.4% vs 54.5%, P = 0.03). The opposite trend was observed for cavitations (14.7% vs 51.5%, P = 0.001). The other CT findings, including pulmonary consolidation (P = 0.205), and pleural effusion (P = 0.641), did not differ significantly between the two groups.

Conclusions

CD4⁺ T lymphocytes have a significant impact on the clinical and radiological characteristics of pulmonary cryptococcosis. The patients with normal CD4⁺ T cell counts were found to have less fever and more nodule-like radiographic findings.

Trial registration

2011NJKY-023-01. Registered on January 10, 2011.

Immune-Mediated Damage Completes the Parabola: Cryptococcus neoformans Pathogenesis Can Reflect the Outcome of a Weak or Strong Immune Response

Cryptococcosis occurs most frequently in immunocompromised individuals. This has led to the prevailing view that this disease is the result of weak immune responses that cannot control the fungus. However, increasingly, clinical and experimental studies have revealed that the host immune response can contribute to cryptococcal pathogenesis, including the recent study of L. M. Neal et al. (mBio 8:e01415-17, 2017, https://doi.org/10.1128/mBio.01415-17) that reports that CD4⁺ T cells mediate tissue damage in experimental murine cryptococcosis. This finding has fundamental implications for our understanding of the pathogenesis of cryptococcal disease; it helps explain why immunotherapy has been largely unsuccessful in treatment and provides insight into the paradoxical observation that HIV-associated cryptococcosis may have a better prognosis than cryptococcosis in those with no known immune impairment. The demonstration that host-mediated damage can drive cryptococcal disease provides proof of concept that the parabola put forth in the damage-response framework has the flexibility to depict complex and changing outcomes of host-microbe interaction.

Different characteristics of cryptococcal meningitis between HIV-infected and HIV-uninfected patients in the Southwest of China

Cryptococcus is the major pathogen that causes fungal meningitis. In the People's Republic of China, especially in the Southwest area, cryptococcal meningitis (CM) in HIV-uninfected patients is more common than in HIV-infected patients. We compared clinical features and laboratory data pertaining to CM in patients with different immunological statuses. Demographic data, clinical manifestations, and laboratory data from inpatients in West China Hospital Sichuan University were collected from June 2009 to June 2014. Patients were grouped according to HIV status. Continuous variables were evaluated by Student t-test or Wilcoxon rank sum tests. Categorical variables were analyzed by χ2 test. Among 85 patients with CM were identified, 53 (62.4%) were HIV-uninfected patients. CM occurred more frequently in males in the HIV-infected group. Compared with HIV-infected patients, HIV-uninfected patients had more leukocytes in their blood and more leukocytes and protein in cerebrospinal fluid. More HIV-uninfected patients had increased cerebrospinal fluid (CSF)/serum albumin ratios, while intrathecal immunoglobulin G (IgG) synthesis was significantly increased. The rate of in-hospital mortality of HIV-infected CM patients was higher. Clinical signs are similar between HIV-uninfected and HIV-infected CM patients. Fewer leukocytes and protein was detected in the CSF and lower local synthesis of IgG in the central nervous system in HIV-infected patients, which reflects their diminished immune response. These characteristics should be noted in order to avoid misdiagnosis. Meningeal enhancement and intrathecal IgG synthesis in the HIV-uninfected group was significantly higher, that may be performance of aggressive inflammatory response and might contribute to a better outcome.

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.

The CD4+ T-lymphocyte count is an important predictor for the prognosis of cryptococcosis

There is great heterogeneity of immunity among patients with cryptococcosis, and severe immunodeficiency can lead to negative clinical outcomes. Underlying disease is a poor surrogate for immune status and inferior in predicting an individual’s prognosis. This study was intended to determine whether T-lymphocyte subgroups would be more suitable indicators regarding the severity of infection and clinical outcomes of such patients. We retrieved clinical data on 101 patients with cryptococcosis and compared the validity of multiple parameters (underlying disease and T-lymphocyte subgroups) in predicting the severity of infection and clinical outcome in these patients. For patients with CD4⁺ T-lymphocyte counts lower than 400/μL, the odds ratio of disseminated cryptococcosis was 23.3 (P = 0.005). There was a moderate negative correlation between CD4⁺ T-cell count and Apache II score (−0.609, P < 0.001). Mortality among patients with low levels of CD4⁺ T lymphocytes was significantly higher than among those with normal levels (23.8% vs 5.3%, P = 0.016). However, the difference was not significant if the patients were grouped by underlying disease (P = 0.067). The CD4⁺ T-lymphocyte count in peripheral blood is a simple and more accurate biomarker for predicting severity of infection and clinical outcome in patients with cryptococcosis.

In vitro interaction of antifungal and antibacterial drugs against Cryptococcus neoformans var. grubii before and after capsular induction

This study evaluated the synergistic interactions between amphotericin B (AMB) and azithromycin (AZM), daptomycin (DAP), linezolid (LNZ), minocycline (MINO), fluconazole (FLZ), flucytosine (5FC), linezolid (LZD), or tigecycline (TIG) against clinical isolates of Cryptococcus neoformans var. grubii before and after capsule induction. High synergism (>75%) was observed for the combinations, AMB+5FC, AMB+TIG, AMB+AZM, AMB+LZD and AMB+MINO but only in the strains after capsule induction. The results show that the presence of the capsule may lower the minimum inhibitory concentrations (MICs) of antifungal agents, but antimicrobial activity can be improved by combining antifungal and antibacterial agents.

Predictors of immune reconstitution syndrome in organ transplant recipients with cryptococcosis: implications for the management of immunosuppression

BACKGROUND

Risk factors including how changes in immunosuppression influence the occurrence of immune reconstitution syndrome (IRS) in solid organ transplant (SOT) recipients with cryptococcosis have not been fully defined.

METHODS

SOT recipients with cryptococcosis were identified and followed for 12 months. IRS was defined based on previously proposed criteria.

RESULTS

Of 89 SOT recipients, 13 (14%) developed IRS. Central nervous system (CNS) disease (adjusted odds ratio [AOR], 6.23; P = .03) and discontinuation of calcineurin inhibitor (AOR, 5.11; P = .02) were independently associated with IRS. Only 2.6% (1/13) of the patients without these risk factors developed IRS compared with 18.8% (6/32) with 1 risk factor, and 50% (6/12) with both risk factors (χ(2) for trend, P = .0001). Among patients with CNS disease, those with neuroimaging abnormalities (P = .03) were more likely to develop IRS, irrespective of serum or CSF cryptococcal antigen titers and fungemia. Graft rejection after cryptococcosis was observed in 15.4% (2/13) of the patients with IRS compared with 2.6% (2/76) of those without IRS (P = .07).

CONCLUSIONS

We determined variables that pose a risk for IRS and have shown that discontinuation of calcineurin inhibitors was independently associated with 5-fold increased risk of IRS in transplant recipients with cryptococcosis.

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.

Predictors of mortality and differences in clinical features among patients with Cryptococcosis according to immune status

Introduction

Cryptococcosis is an invasive fungal infection causing substantial morbidity and mortality. Prognostic factors are largely derived from trials conducted prior to the modern era of antifungal and potent combination antiretroviral therapies, immunosuppression, and transplantation. Data describing the clinical features and predictors of mortality in a modern cohort are needed.

Methods

We conducted a retrospective cohort study of patients at our institution diagnosed with cryptococcosis from 1996 through 2010. Data included demographics, clinical features, diagnostics, treatment, and outcomes.

Results

We identified 302 individuals: 108 (36%) human immunodeficiency virus (HIV)-positive, 84 (28%) organ transplant recipients (OTRs), and 110 (36%) non-HIV, non-transplant (NHNT) patients including 39 with no identifiable immunodeficiency. Mean age was 49 years, 203 (67%) were male and 170 (56%) were white. All-cause mortality at 90 days was 21%. In multivariable logistic regression analyses, cryptococcemia (OR 5.09, 95% CI 2.54–10.22) and baseline opening pressure >25 cmH₂O (OR 2.93, 95% CI 1.25–6.88) were associated with increased odds of mortality; HIV-positive patients (OR 0.46, 95% CI 0.19–1.16) and OTRs (OR 0.46, 95% CI 0.21–1.05) had lower odds of death compared to NHNT patients.

Conclusions

Predictors of mortality from cryptococcosis in the modern period include cryptococcemia, high intracranial pressure, and NHNT status while drug(s) used for induction and historical prognostic factors including organ failure syndromes and hematologic malignancy were not associated with mortality.

Approaches to antifungal therapies and their effectiveness among patients with cryptococcosis

The goal of this study was to determine the degree to which the persistence of cryptococcosis, overall 1-year mortality, and 1-year mortality due to cryptococcosis were influenced by initial antifungal treatment regimen in a cohort of adults with cryptococcosis treated at a tertiary care medical center. Risk factors, underlying conditions, treatment, and mortality information were obtained for 204 adults with cryptococcosis from Duke University Medical Center (DUMC) from 1996 to 2009. Adjusted risk ratios (RR) for persistence and hazard ratios (HR) for mortality were estimated for each exposure. The all-cause mortality rate among patients with nonsevere disease (20%) was similar to that in the group with disease (26%). However, the rate of cryptococcosis-attributable mortality with nonsevere disease (5%) was much lower than with severe disease (20%). Flucytosine exposure was associated with a lower overall mortality rate (HR, 0.4; 95% confidence interval [CI], 0.2 to 0.9) and attributable mortality rate (HR, 0.5; 95% CI, 0.2 to 1.2). Receiving a nonrecommended antifungal regimen was associated with a higher relative risk of persistent infection at 4 weeks (RR, 1.9; 95% CI, 0.9 to 4.3), and the rate of attributable mortality among those not receiving the recommended dose of initial therapy was higher than that of those receiving recommended dosing (HR, 2.3; 95% CI, 1.0 to 5.0). Thus, the 2010 Infectious Diseases Society of America (IDSA) guidelines are supported by this retrospective review as a best-practice protocol for cryptococcal management. Future investigations should consider highlighting the distinction between all-cause mortality and attributable mortality so as not to overestimate the true effect of cryptococcosis on patient death.

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.

Comparison and temporal trends of three groups with cryptococcosis: HIV-infected, solid organ transplant, and HIV-negative/non-transplant

BACKGROUND

The Infectious Disease Society of America (IDSA) 2010 Clinical Practice Guidelines for the management of cryptococcosis outlined three key populations at risk of disease: (1) HIV-infected, (2) transplant recipient, and (3) HIV-negative/non-transplant. However, direct comparisons of management, severity and outcomes of these groups have not been conducted.

METHODOLOGY/PRINCIPAL FINDINGS

Annual changes in frequency of cryptococcosis diagnoses, cryptococcosis-attributable mortality and mortality were captured. Differences examined between severe and non-severe disease within the context of the three groups included: demographics, symptoms, microbiology, clinical management and treatment. An average of nearly 15 patients per year presented at Duke University Medical Center (DUMC) with cryptococcosis. Out of 207 study patients, 86 (42%) were HIV-positive, 42 (20%) were transplant recipients, and 79 (38%) were HIV-negative/non-transplant. HIV-infected individuals had profound CD4 lymphocytopenia and a majority had elevated intracranial pressure. Transplant recipients commonly (38%) had renal dysfunction. Nearly one-quarter (24%) had their immunosuppressive regimens stopped or changed. The HIV-negative/non-transplant population reported longer duration of symptoms than HIV-positive or transplant recipients and 28% (22/79) had liver insufficiency or underlying hematological malignancies. HIV-positive and HIV-negative/non-transplant patients accounted for 89% of severe disease cryptococcosis-attributable deaths and 86% of all-cause mortality.

CONCLUSIONS/SIGNIFICANCE

In this single-center study, the frequency of cryptococcosis did not change in the last two decades, although the underlying case mix shifted (fewer HIV-positive cases, stable transplant cases, more cases with neither). Cryptococcosis had a relatively uniform and informed treatment strategy, but disease-attributable mortality was still common.

Different presentations and outcomes between HIV-infected and HIV-uninfected patients with Cryptococcal meningitis

BACKGROUND AND PURPOSE

Cryptococcus species are the most common causative agents of fungal meningitis. Different populations may show different clinical manifestations and outcomes. In this retrospective study, we investigated these differences in patients with and without HIV infection.

METHODS

From 1995 to 2009, we collected data from HIV-infected or HIV-uninfected patients aged 18 years or over who had cryptococcal meningitis (CM) in a medical center in Taiwan. We reviewed and analyzed their demographic data, clinical manifestations, therapeutic strategies and outcomes.

RESULTS

Among the 72 patients with CM, 19 HIV-infected patients were predominantly younger males, and all of them had AIDS status when CM was diagnosed. In contrast, the 53 HIV-uninfected patients were mostly older males with underlying diseases. The time from initial symptoms to diagnosis was shorter in HIV-infected patients (median 10 vs. 18 days, p = 0.048). The HIV-infected patients presented with less pleocytosis (p = 0.003) and lower protein levels in the cerebrospinal fluid (CSF), but a higher proportion had positive results for cryptococci in the CSF (90% vs. 60%, p = 0.02) and blood (53% vs. 21%, p = 0.009) cultures. Surgical drains and repeated lumbar punctures for the management of increased intracranial pressure were performed in 47% of the HIV-infected patients and 38% of the HIV-uninfected patients. A lower mortality rate was observed in the HIV-infected patients (p = 0.038). On multivariate analysis, initial CD4 count ≤20/mm(3) was an indicator of death or relapse in HIV-infected patients. In the HIV-uninfected group, the initial high cryptococcal antigen titer in the CSF (≥1:512) and hydrocephalus were related to unsatisfactory outcomes.

CONCLUSION

In addition to well-known differences, we found a lower mortality in HIV-infected patients than in HIV-uninfected patients. Cryptococci and inflammation in the central nervous system may play important roles in the pathogenesis of CM. Low intensity of inflammation and effective surgical CSF drains for increased intracranial pressure and cryptococci removal may contribute to lower mortality in HIV-infected patients.

The impact of the host on fungal infections

Outcomes of fungal infections in immunocompromised individuals depend on a complex interplay between host and pathogen factors, as well as treatment modalities. Problems occur when host responses to an infection are either too weak to effectively help eradicate the pathogen, or when they become too strong and are associated with host damage rather than protection. Immune reconstitution syndrome (IRS) can be generally defined as a restoration of host immunity in a previously immunosuppressed patient that becomes dysregulated and overly robust, resulting in host damage and sometimes death. IRS associated with opportunistic mycoses presents as new or worsening clinical symptoms or radiographic signs consistent with an inflammatory process that occur during receipt of an appropriate antifungal, and that cannot be explained by a newly acquired infection. Because there are currently no established tests or biomarkers for IRS, it can be difficult to distinguish from progression of the original infection, although culture and biomarkers for the fungal pathogen or infection are typically negative during diagnostic workup. IRS was originally characterized in human immunodeficiency virus-infected patients receiving antiretroviral therapy, but has subsequently been described in solid-organ transplant recipients, neutropenic patients, women in the postpartum period, and recipients of tumor necrosis factor-α inhibitor therapy. In each of these cases, recovery of the host's immunity during treatment of an initial infection results in a powerful proinflammatory environment that overshoots and leads to host damage. Optimal management of IRS has not been established at present, but often involves treatment with a corticosteroid or other anti-inflammatory compounds. This article uses a number of patient cases to explore the intricacies of diagnosing and managing a patient with IRS, as well as the other extreme, namely patients who are so immunocompromised without immune recovery that they essentially become breeding grounds for a wide range of opportunistic pathogens, often simultaneously.

Influence of capsule size on the in vitro activity of antifungal agents against clinical Cryptococcus neoformans var. grubii strains

Cryptococcosis causes disseminated disease in AIDS patients. In contrast to what occurs in laboratory conditions, a large capsule is produced by Cryptococcus neoformans in vivo during infection. The aim of this study was to compare the in vitro activity of different antifungal agents against 34 clinical isolates of C. neoformans var. grubii without or with capsule induction (CLSI, CLSI-C, respectively), following the CLSI M27A3 document. Capsule induction was obtained by addition of NaHCO(3) and incubation with CO(2). The geometric means of the MICs, in µg ml(-1), for CLSI and CLSI-C cultures, respectively, were 1.9 and 9.8 for fluconazole; 0.04 and 0.08 for itraconazole; 0.04 and 0.05 for voriconazole; 0.16 and 0.38 for amphotericin B; and 1.6 and 5.6 for 5-flucytosine. Thus fluconazole showed the highest MICs after capsule induction. Determination of antifungal activity after capsule induction may be clinically relevant and could be used to evaluate the correlation between in vitro results and clinical outcome.