Cryptococcal infections in solid organ transplant recipients over a 15-year period at a state transplant center

Specificities of Meningitis and Meningo-Encephalitis After Kidney Transplantation: A French Retrospective Cohort Study

Kidney transplant recipients develop atypical infections in their epidemiology, presentation and outcome. Among these, meningitis and meningoencephalitis require urgent and adapted anti-infectious therapy, but published data is scarce in KTRs. The aim of this study was to describe their epidemiology, presentation and outcome, in order to improve their diagnostic and management. We performed a retrospective, multicentric cohort study in 15 French hospitals that included all 199 cases of M/ME in KTRs between 2007 and 2018 (0.9 case per 1,000 KTRs annually). Epidemiology was different from that in the general population: 20% were due to Cryptococcus neoformans, 13.5% to varicella-zoster virus, 5.5% to Mycobacterium tuberculosis, and 4.5% to Enterobacteria (half of which produced extended spectrum beta-lactamases), and 5% were Post Transplant Lymphoproliferative Disorders. Microorganisms causing M/ME in the general population were infrequent (2%, for Streptococcus pneumoniae) or absent (Neisseria meningitidis). M/ME caused by Enterobacteria, Staphylococci or filamentous fungi were associated with high and early mortality (50%-70% at 1 year). Graft survival was not associated with the etiology of M/ME, nor was impacted by immunosuppression reduction. Based on these results, we suggest international studies to adapt guidelines in order to improve the diagnosis and the probabilistic treatment of M/ME in SOTRs.

Pulmonary Cryptococcosis

Pulmonary cryptococcosis describes an invasive lung mycosis caused by Cryptococcus neoformans or Cryptococcus gattii complex. It is often a high-consequence disease in both immunocompromised and immunocompetent populations, and may be misdiagnosed as pulmonary malignancy, leading to a delay in therapy. Epidemiology follows that of cryptococcal meningoencephalitis, with C. gattii infection more common in certain geographic regions. Diagnostic tools include histopathology, microscopy and culture, and the detection of cryptococcal polysaccharide antigen or Cryptococcus-derived nucleic acids. All patients with lung cryptococcosis should have a lumbar puncture and cerebral imaging to exclude central nervous system disease. Radiology is key, both as an adjunct to laboratory testing and as the initial means of detection in asymptomatic patients or those with non-specific symptoms. Pulmonary cryptococcomas (single or multiple) may also be associated with disseminated disease and/or cryptococcal meningitis, requiring prolonged treatment regimens. Optimal management for severe disease requires extended induction (amphotericin B and flucytosine) and consolidation therapy (fluconazole) with close clinical monitoring. Susceptibility testing is of value for epidemiology and in regions where relatively high minimum inhibitory concentrations to azoles (particularly fluconazole) have been noted. Novel diagnostic tools and therapeutic agents promise to improve the detection and treatment of cryptococcosis, particularly in low-income settings where the disease burden is high.

Parkinsonism and prolonged cognitive decline as a manifestation of cryptococcal meningitis in a renal transplant patient

We report a case of a 67-year-old male recipient of a second renal allograft, presenting with a 9-month history of progressive cognitive and physical decline with features of Parkinsonism. He was HIV-negative. Serum and cerebrospinal fluid (CSF) cryptococcal antigen was positive though CSF culture was sterile. He had progressive deterioration despite induction and consolidation antifungal treatment. Postmortem brain examination confirmed a large burden of yeast forms in the substantia nigra with widespread chronic meningitis. The significant delay in presentation and diagnosis owing to the atypical, subacute neurocognitive features serves as a timely reminder of the variety of neurological presentations that may be associated with cryptococcal infection in solid organ transplant recipients.

Emerging fungal pathogens in solid organ transplantation

PURPOSE OF REVIEW

This review examines recent cases and updated literature on emerging or newly resistant fungal infections in solid organ transplantation.

RECENT FINDINGS

Candida auris, a newly described candida capable of drug resistance and persistence in the environment, is a growing concern with both published cases on donor-derived transmission and a hospital outbreak involving liver transplant recipients. Infections with non-albicans candida species are also increasing in incidence in SOT recipients, leading to increasing antifungal resistance and higher mortality. Aspergillus usti has emerged in immunocompromised patients on antifungal prophylaxis. Cryptococcus species continue to be responsible for a number of infections in SOT recipients. Dimorphic fungi, endemic to geographic areas and responsible for sporadic infections in SOT recipients are noted to have an expanding geographic area. Emergomyces are newly classified groups of five species of dimorphic fungi noted to disseminated disease in immunocompromised patients including SOT recipients.

SUMMARY

Emerging fungal species and the development of resistance in well entrenched fungal pathogens impacts SOT recipients and those caring for them. Knowledge of these trends aids in the successful identification and optimal treatment of these challenging conditions.

Update on Pulmonary Cryptococcosis

Pulmonary cryptococcosis is a common but underdiagnosed opportunistic fungal infection in both immunocompromised and immunocompetent patients. The causal agents include at least eight evolutionary distinct haploid lineages as well as their hybrids of the human pathogenic Cryptococcus complex. In this update, we review recent advances in epidemiology, mode of transmission, risk factors, diagnostic methods, and therapy of pulmonary cryptococcosis. Our review suggests significant challenges and opportunities for research, from bedside to benchside and back to bedside.

Fungal pneumonia in kidney transplant recipients

Fungal pneumonia is a dreaded complication encountered after kidney transplantation, complicated by increased mortality and often associated with graft failure. Diagnosis can be challenging because the clinical presentation is non-specific and diagnostic tools have limited sensitivity and specificity in kidney transplant recipients and must be interpreted in the context of the clinical setting. Management is difficult due to the increased risk of dissemination and severity, multiple comorbidities, drug interactions and reduced immunosuppression which should be applied as an important adjunct to therapy. This review will focus on the main causes of fungal pneumonia in kidney transplant recipients including Pneumocystis, Aspergillus, Cryptococcus, mucormycetes and Histoplasma. Epidemiology, clinical presentation, laboratory and radiographic features, specific characteristics will be discussed with an update on diagnostic procedures and treatment.

HIV Infection Does Not Increase 10-Week Mortality of Chinese Cryptococcal Meningitis Patients

The role of HIV infection in precipitating different clinical features in cryptococcal meningitis (CM) patients remains controversial. One hundred twelve CM patients living with HIV/AIDS (CM+HIV+ patients) and 112 CM patients living without HIV/AIDS (CM+HIV- patients) were enrolled after propensity score matching. Demographic characteristics, symptoms, routine blood tests, and biochemical and cerebrospinal fluid (CSF) profiles were compared between the two groups. Kaplan-Meier analysis and Cox proportional hazards model was used to assess 10-week mortality. CM+HIV+ patients frequently occurred in young (mean age 40.3 ± 10.5) and male (89.3%) populations who also experienced leukopenia, neutropenia, lymphocytopenia, thrombocytopenia, and hypoalbuminemia, less headaches (66.9%), and higher cryptococcemia (23.2%) (all p < .050); they also had higher glucose (2.6 ± 1.1 mmol/L), increased smear positivity (78.8%), and decreased white blood cells [8.0 (2.0-28.0) × 10⁶/L] in initial CSF assay (all p < .050). The 10-week cumulative survival rate was 84.6% for CM+HIV+ patients and 88.5% for CM+HIV- patients (p = .345). Age <35.0 years (hazard ratio (HR) 3.0 (1.0-8.9), p = .046), intracranial pressure (ICP) >250.0 mmH₂O (HR: 4.8 (1.1-21.6), p = .041), and treatment lacking amphotericin B [HR: 6.5 (1.9-21.4), p = .003] were independent risk factors for 10-week mortality in CM+HIV+ patients. There are significant clinical differences in CM patients living with or without HIV/AIDS. However, the 10-week survival rate was similar between the two groups. Younger population, high ICP, and treatment lacking amphotericin B were independent risk factors for 10-week mortality of Chinese CM+HIV+ patients.

Landmark clinical observations and immunopathogenesis pathways linked to HIV and Cryptococcus fatal central nervous system co-infection

Cryptococcal meningitis remains one of the leading causes of death among HIV-infected adults in the fourth decade of HIV era in sub-Saharan Africa, contributing to 10%-20% of global HIV-related deaths. Despite widespread use and early induction of ART among HIV-infected adults, incidence of cryptococcosis remains significant in those with advanced HIV disease. Cryptococcus species that causes fatal infection follows systemic spread from initial environmental acquired infection in lungs to antigenaemia and fungaemia in circulation prior to establishment of often fatal disease, cryptococcal meningitis in the CNS. Cryptococcus person-to-person transmission is uncommon, and deaths related to blood infection without CNS involvement are rare. Keen to the persistent high mortality associated with HIV-cryptococcal meningitis, seizures are common among a third of the patients, altered mental status is frequent, anaemia is prevalent with ensuing brain hypoxia and at autopsy, brain fibrosis and infarction are evident. In addition, fungal burden is 3-to-4-fold higher in those with seizures. And high immune activation together with exacerbated inflammation and elevated PD-1/PD-L immune checkpoint expression is immunomodulated phenotypes elevated in CSF relative to blood. Lastly, though multiple Cryptococcus species cause disease in this setting, observations are mostly generalised to cryptococcal infection/meningitis or regional dominant species (C neoformans or gattii complex) that may limit our understanding of interspecies differences in infection, progression, treatment or recovery outcome. Together, these factors and underlying mechanisms are hypotheses generating for research to find targets to prevent infection or adequate therapy to prevent persistent high mortality with current optimal therapy.

Skin cryptococcosis in an immunocompromised renal-transplant recipient

Immunosuppression after solid-organ transplantation can lead to opportunistic infections as cryptococcosis. A 69-year-old female, cadaveric renal-transplant recipient, manifested with ulcerative lesions on the 7th month of immunosuppression. Histological examination confirmed the diagnosis of cryptococcosis. Treatment with systemic and topical antifungal therapy for 7 months concluded in significant cutaneous improvement. This case presentation encourages high clinical suspicion of opportunistic pathogens such as Cryptococcus spp. and highlights the necessity of appropriate management.

Unique clinical features of cryptococcal meningitis among Chinese patients without predisposing diseases against patients with predisposing diseases

The clinical features of cryptococcal meningitis (CM) in patients without predisposing diseases (PD) remain unclear. In sum, 162 of the 167 patients without PD and 162 of the 309 patients with PD were enrolled after propensity score matching. Demographic characteristics, symptoms, blood, and cerebrospinal fluid (CSF) characteristics were compared between the two groups. Kaplan-Meier curves and a Cox proportional hazards model were used to assess the factors associated with 10-week mortality. In total, approximately 35.1% of CM patients were without PD. CM patients without PD had blood profiles of higher white blood cells (WBC) [8.9(6.7-11.0) × 109/l], hemoglobin (128.4 ± 20.9 g/l), platelets [(226.2 ± 64.1) × 109/l], and serum albumin (41.2 ± 5.8 g/l) (all P ≤ .001) and CSF profiles of lower glucose (2.0 ± 1.2 mmol/l), pleocytosis [65.0 (18.0-160.0) × 106/l] and higher total protein [0.9 (0.7-1.4)g/l] (all P < .05). CM patients without PD had lower Cryptococcus culture positivity in CSF (62.5% vs. 74.1%, P = .039) but higher 2-week of CSF culture sterilization rates (69.4% vs. 51.3%, P = .031). The overall 10-week survival rate was 84.7% in patients without PD and 81.1% in patients with PD (Log-rank P = .439). CSF glucose <1.5 mmol/l, CSF fungal burden >20 cells/high power field and treatment lacking amphotericin B had a 3-4 times higher risk of death in patients without PD, whereas serum albumin <35 g/l, CSF glucose < 1.5 mmol/l, and CSF WBC <55 × 106 cell/l were risk factors for patients with PD. CM patients without PD had unique blood and CSF profiles, especially, had lower Cryptococcus culture positivity in CSF, and higher 2-week CSF culture sterilization. Low CSF glucose levels, higher fungal burden, and treatment without amphotericin B were risk factors for 10-week mortality.

Cryptococcosis in Patients following Kidney Transplantation: A 9-Year Retrospective Clinical Analysis at a Chinese Tertiary Hospital

Background

Cryptococcosis following kidney transplantation (KT) is rare but is associated with considerably increased risk of mortality. At present, data on the association between cryptococcosis and KT in mainland China remain relatively limited.

Objectives

This study aims to review our experience related to the management of cryptococcosis following KT at a Chinese tertiary hospital.

Methods

All patients with cryptococcosis following KT admitted to our hospital from January 2010 to December 2018 were reviewed.

Results

A total of 37 patients with cryptococcosis were enrolled (males: 62.2%). The mean age of the patients was 49.5 ± 9.38 (20-64) years. The average time to infection following KT was 7.0 ± 5.50 years (5 months to 21 years), and 30 patients (81.1%) had cryptococcosis onset >2 years following transplantation. The most common site of infection was the central nervous system, followed by the pulmonary system and skin. Most patients received fluconazole or voriconazole with or without flucytosine as their initial treatment regimen at our hospital. The 2-week mortality rate was 8.1% (3/37), and five patients (13.5%) died within 6 months of being diagnosed with cryptococcosis. Remarkably, all patients who received high-dose fluconazole (800 mg daily) or voriconazole ± flucytosine survived.

Conclusions

Cryptococcosis in kidney transplant recipients is typically a late-occurring infection, with most patients having cryptococcosis onset >2 years following KT at our hospital. The central nervous system, pulmonary system, and skin are the main sites of infection. Voriconazole or high-dose fluconazole can be used as an alternative therapy for post-KT cryptococcosis.

Shift in Epidemiology of Cryptococcal Infections in Ottawa with High Mortality in Non-HIV Immunocompromised Patients

Cryptococcus neoformans is a fungus that can cause life-threatening infections. While human immunodeficiency virus (HIV)-positive status historically had the highest risk for cryptococcal infection and was associated with high mortality rates, there have been changes in HIV treatment and the epidemiology of other acquired immunodeficiencies, such as hematological malignancies. We conducted a retrospective case series analysis of patients who had cryptococcal infections documented at the Ottawa Hospital from 2005 to 2017. The Ottawa Hospital is a tertiary care hospital and provides complex care such as chemotherapy and transplantations. There were 28 confirmed cryptococcal infections. The most common underlying condition associated with cryptococcal infection was hematological malignancy (n = 8, 29%), followed by HIV (n = 5, 18%) and solid organ transplantation (n = 4, 14%). Furthermore, while there was a decrease in the number of cryptococcal infections in HIV patients after 2010 (four to one case), the number of cases in non-HIV immunocompromised patients increased from four in the years 2005-2010 to fourteen in 2011-2017. There were nine cryptococcal-attributable deaths. The case fatality rate was highest among patients with underlying hematological malignancies (63%), followed by solid organ transplant (50%) and HIV patients (20%). In conclusion, this study showed that there may be an epidemiological shift of cryptococcal infection in Ottawa. Additionally, infections may be associated with a worse prognosis in patients with a hematological malignancy and solid organ transplant than in patients with HIV infection in the modern era. Better prevention and/or treatment is warranted for high-risk populations.

Genotypic diversity and clinical outcome of cryptococcosis in renal transplant recipients in Brazil

Genotypic diversity and fluconazole susceptibility of 82 Cryptococcus neoformans and Cryptococcus gattii isolates from 60 renal transplant recipients in Brazil were characterized. Clinical characteristics of the patients and prognostic factors were analysed. Seventy-two (87.8%) isolates were C. neoformans and 10 (12.2%) were C. gattii. VNI was the most common molecular type (40 cases; 66.7%), followed by VNII (9 cases; 15%), VGII (6 cases; 10%), VNB (4 cases; 6.7%) and VNI/II (1 case; 1.7%). The isolates showed a high genetic diversity in the haplotype network and six new sequence types were described, most of them for VNB. There was a bias towards skin involvement in the non-VNI population (P = .012). VGII isolates exhibited higher fluconazole minimum inhibitory concentrations compared to C. neoformans isolates (P = 0.008). The 30-day mortality rate was 38.3%, and it was significantly associated with fungemia and absence of headache. Patients infected with VGII had a high mortality rate at 90 days (66.7%). A variety of molecular types produce disease in renal transplant recipients in Brazil and highlighted by VGII and VNB. We report the clinical appearance and impact of the molecular type, fluconazole susceptibility of the isolates, and clinical characteristics on patient outcome in this population.

Pneumonia in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These guidelines from the AST Infectious Diseases Community of Practice review the diagnosis and management of pneumonia in the post-transplant period. Clinical presentations and differential diagnosis for pneumonia in the solid organ transplant recipient are reviewed. A two-tier approach is proposed based on the net state of immunosuppression and the severity of presentation. With a lower risk of opportunistic, hospital-acquired, or exposure-specific pathogens and a non-severe presentation, empirical therapy may be initiated under close clinical observation. In all other patients, or those not responding to the initial therapy, a more aggressive diagnostic approach including sampling of tissue for microbiological and pathological testing is warranted. Given the broad range of potential pathogens, a microbiological diagnosis is often key for optimal care. Given the limited literature comparatively evaluating diagnostic approaches to pneumonia in the solid organ transplant recipient, much of the proposed diagnostic algorithm reflects clinical experience rather than evidence-based data. It should serve as a template which may be modified according to local needs. The same holds true for the suggested empiric therapies, which need to be adapted to the local resistance patterns. Further study is needed to comparatively evaluate diagnostic and empiric treatment strategies in SOT recipients.

Cryptococcosis in solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of cryptococcosis in the pre- and post-transplant period. The current update now includes a discussion of cryptococcosis, which is the third most common invasive fungal infection in SOT recipients. Infection often occurs a year after transplantation; however, early infections occur and donor-derived infections have been described within 3 months after transplant. There are two main species that cause infection, Cryptococcus neoformans and C gattii. Clinical onset may be insidious, but headaches, fevers, and mental status changes should warrant diagnostic testing. The lateral flow cryptococcal antigen assay is now the preferred test from serum and cerebrospinal fluid due to its rapidity, accuracy, and cost. A lumbar puncture with measurement of opening pressure is recommended for patients with suspected or proven cryptococcosis. Lipid amphotericin B plus 5-flucytosine is used as initial treatment of meningitis, disseminated infection, and moderate-to-severe pulmonary infection, followed by fluconazole as consolidation therapy. Fluconazole is effective for mild-to-moderate pulmonary infection. Immunosuppression reduction as part of management may lead to immune reconstitution syndrome that may resemble active disease.

Comparison and Correlation of Magnetic Resonance Imaging and Clinical Severity in Nonhuman Immunodeficiency Virus Patients with Cryptococcal Infection of Central Nervous System

Background:

The incidence of cryptococcal meningitis among immunocompetent patients increases, especially in China and imaging plays an important role. The current study was to find the correlation between magnetic resonance imaging (MRI) manifestation and clinical severity in nonhuman immunodeficiency virus patients with cryptococcal infection of central nervous system (CNS).

Methods:

A total of 65 patients with CNS cryptococcal infection from August 2014 to October 2016 were retrospectively included in this study. All the patients had MRI data and clinical data. The patients were divided into two groups according to whether the patients were confirmed with identifiable underlying disease. Comparison and correlation of MRI and clinical data in both groups were investigated using independent sample t-test, Chi-square test, Mann-Whitney test and Spearman rank correlation analysis.

Results:

In all 65 patients, 41 cases (41/65, 63.1%; Group 1) had normal immunity and 24 cases (24/65, 36.9%; Group 2) had at least one identifiable underlying disease. Fever, higher percentage of neutrophil (NEUT) in white blood cell (WBC), and increased cell number of cerebral spawell correlated with the number of cells andil fluid (CSF) were much common in patients with underlying disease (Group 1 vs. Group 2: Fever: 21/41 vs. 21/24, χ² = 8.715, P = 0.003; NEUT in WBC: 73.15% vs. 79.60%, Z = −2.370, P = 0.018; cell number of CSF: 19 vs. 200, Z = −4.298, P < 0.001; respectively). Compared to the patients with normal immunity, the lesions are more common in the basal ganglia among patients with identifiable underlying disease (Group 1 vs. Group 2: 20/41 vs. 20/24, χ² = 7.636, P = 0.006). The number of the involved brain areas in patients with identifiable underlying disease were well correlated with the number of cells and pressure of CSF (r = −0.472, P = 0.031; r = 0.779, P = 0.039; respectively).

Conclusions:

With the increased number of the involved brain areas in patients with identifiable underlying disease, the body has lower immunity against the organism which might result in higher intracranial pressure and more severe clinical status.

Cryptococcal infection in lung transplant recipients: A 5-year retrospective review at an Australian transplant center

Cryptococcosis is a common invasive fungal infection (IFI) in solid organ transplant (SOT) recipients. Little is known about cryptococcosis in lung transplant (LTx) recipients despite having one of the highest risks of infection. The aim of this study was to describe demographic and clinical features of cryptococcal infection in LTx recipients. We performed a retrospective, observational study of cryptococcal infection in LTx recipients at The Alfred Hospital in Melbourne, Australia, from 2012 to 2017. A total of 11 cases were identified. Seven patients (64%) were male and the median age was 54.7 years (range 34-69 years). Diagnosis occurred at a median of 233 days (range 1-3650 days) post-transplant. Nine patients (82%) had isolated pulmonary infection of whom 7 (78%) were asymptomatic. All were treated with oral antifungal therapy and 1 required surgical resection of infected lung. Two patients (18%) had disseminated infection; 1 with pulmonary and central nervous system (CNS) infection and 1 with isolated CNS infection. Both patients presented with headache and brain imaging demonstrated cerebral edema, myelinosis, and leptomeningeal enhancement. One of these patients died. This study highlights the fact that cryptococcal infection should remain a consideration in asymptomatic LTx recipients, especially in the presence of non-specific nodules on chest imaging, and that the presence of headache in these patients requires urgent investigation for CNS infection.

Multifocal Soft Tissue Cryptococcosis in a Renal Transplant Recipient: The Importance of Suspecting Atypical Pathogens in the Immunocompromised Host

Cryptococcal infection has been documented in 2.8% of solid-organ transplant recipients, with the median time to disease onset being 21 months. Renal transplantrecipients accountforthe majority of cases. Most patients present with central nervous system or disseminated disease, with only a minority having cutaneous manifestations. We present the case of a 47-year-old female renal transplant recipient who presented with refractory acute cellulitis 7 months after transplant. She had received thymoglobulin induction and was on a maintenance immunosuppressive regimen oftacrolimus, mycophenolic acid, and prednisone (5 mg/d). She did not respond to broad-spectrum antibacterial therapy for presumed bacterial cellulitis. Skin and soft tissue biopsies subsequently showed the presence of yeast; Cryptococcus neoformans was recovered in culture. Blood cultures, chest radiography, and cerebrospinal fluid sampling were negative, which resulted in a diagnosis of multifocal soft tissue cryptococcosis, a form of disseminated disease. Serum cryptococcal antigen testing was strongly positive (≥ 1:2560). The patient's immunosuppression was reduced, and she received treatment with liposomal-amphotericin B and flucytosine for 2 weeks, which resulted in symptomatic improvement. This was followed by 1 year of consolidation and subsequent maintenance therapy with fluconazole. This case should increase awareness of the broader differential diagnosis of soft tissue infection in immunocompromised patients. Her case mimicked bacterial cellulitis, which delayed administration of effective therapy. Although our patient was initially diagnosed via biopsy, early clinical suspicion and serum cryptococcal antigen testing can lead to the correct diagnosis more rapidly. As transplant patients return to their community providers, heightened vigilance for unusual infections and presentations is warranted.The possibility of a cryptococcal cause for acute soft tissue infection should be considered, even in the absence of pulmonary or central nervous system involvement.