Central nervous system infection due to Cryptococcus gattii sensu lato in India: Analysis of clinical features, molecular profile and antifungal susceptibility

Virulence profiling of Cryptococcus gattii isolates in China: insights from a multi-center study

IMPORTANCE

Our study indicates that the molecular typing of Cryptococcus gattii is unrelated to virulence. The integration of animal experiments and clinical prognosis demonstrated that pathogenicity did not exhibit a direct correlation with in vitro virulence phenotypes or molecular genotypes, emphasizing the intricate nature of virulence. In conclusion, our research holds the potential to provide valuable insights into understanding the microbiological attributes of C. gattii in China.

Reversible deafness and blindness in Cryptococcus gattii meningitis with a ventriculoperitoneal shunt: A case report and literature review

Cryptococcus gattii (C. gattii) has been considered a leading cause of meningitis in immunocompetent hosts in tropical and subtropical regions. Visual loss is common but hearing impairment is relatively infrequent in C. gattii meningitis. Notably, there have been limited studies on the etiology, and especially therapy of auditory and ocular complications associated with C. gattii meningitis. Here we report a case of reversible deafness and blindness treated with a ventriculoperitoneal shunt (VPS) surgery in C. gattii meningitis. This case indicated that elevated intracranial pressure (ICP) may play a role in the concurrent hearing and vision impairments associated with C. gattii meningitis and the early VPS surgery after the initiation of the antifungal therapy may effectively improve both hearing and vision in this condition.

Trends of CNS Cryptococcosis during Pre- and Post-HIV era: A 38 years' retrospective cohort analysis from south India

OBJECTIVE

Central nervous system cryptococcosis (CNSc) is an AIDS defining opportunistic infection. This retrospective study aimed to analyze the changing epidemiology of CNSc cases from the period of pre- to post-emergence of HIV epidemic in south India.

METHODS

Confirmed cases of CNSc from 1978 to 2015 were analyzed for demographic and clinical details with special reference to the cases diagnosed in south India during the period 1952-1977. Geographical distribution, affected age groups, clinical aspects, and comorbidities in relation to immune status were analysed RESULTS: The highest number of CNSc cases (n = 125) were recorded in 2006, with 89.6% HIV positivity. The highest HIV-positivity (93.6%) was documented in the years 2002 and 2009. CNSc cases have majorly changed after the introduction and spread of HIV in terms of predisposing factors, comorbidities, severity, affected age groups and treatment. Notably, an overall rise was observed in non-HIV associated CNSc cases from 1997 (8.1%) to 2015 (16.9%).

CONCLUSION

The peak of CNSc had already reached in south India during 2005-2006. However, the number of new infections has slowly decreased in last ten years. Progressive awareness and, early diagnosis of HIV and cryptococcosis, adequate availability of HAART and potential antifungal therapy has played crucial roles in changing epidemiology of the CNSc and its associated mortality.

Advanced approach for antifungal susceptibility and characterization of resistance properties in clinical and environmental isolates of Cryptococcus species complex

BACKGROUND

Meningitis due to Cryptococcus neoformans/gattii is a fatal infection affecting immunocompromised population worldwide. Amphotericin B (AmB), fluconazole (FLC) and 5-flucytosine are the drugs of choice to treat the infection. We studied antifungal susceptibility pattern of clinical and environmental cryptococcal species using newer approach and analyze their resistant characteristics.

METHODS

Eighty clinical (54 C. neoformans and 26 C. gattii) and 18 environmental (14 C. neoformans and 4 C. gattii) isolates were subjected to antifungal susceptibility testing by automated (VITEK2C) method. Minimum inhibitory concentrations (MIC) were analyzed statistically. Genomic DNA of FLC resistant isolates was extracted and amplified to detect presence of CnAFR1 gene.

RESULTS

C. neoformans showed 1.85% and 21.4% AmB resistance, and 1.85% and 28.5% FLC- resistance, whereas C. gattii showed 25% and 50% FLC-resistance among clinical and environmental isolates respectively. MIC values were significantly (p < 0.05) different for the isolates from 2 sources. CnAFR1 gene sequence analysis revealed phylogenetic relationship among the resistant isolates.

CONCLUSIONS

This pioneering study provides an insight into the sensitivity patterns of clinical and environmental cryptococcal isolates from south India. The recent emergence of AmB-resistance may transpire as a challenge for the clinicians. As the clinical and environmental isolates are phylogenetically evolved from CnAFR1 gene of Filobasidiella neoformans, the resistance is most probably an inherent attribute. This study emphasizes the need for speciation and antifungal susceptibility testing of cryptococcal isolates from clinical sources to institute appropriate antifungal therapy and to reduce the mortality and morbidity.

Clinical insights and epidemiology of central nervous system infection due to Cryptococcus neoformans/gattii species complexes: A prospective study from South India

In the last two decades, central nervous system (CNS) cryptococcosis (CNSc) has emerged as a major opportunistic infection in the immunocompromised population of India. We have analyzed the clinical features of CNSc and epidemiology of Cryptococcus neoformans and Cryptococcus gattii. A total of 160 clinical isolates of C. neoformans/gattii recovered from CNSc patients were analyzed. The origin, clinical parameters, and imaging features of the patients were recorded, and clinical parameters were analyzed based on their human immunodeficiency virus (HIV) status and infecting species, namely, C. neoformans or C. gattii. Serotypes and mating types of the isolates were determined. Molecular typing was performed by polymerase chain reaction (PCR) fingerprinting using M13 microsatellite primer (GTG)5, and multilocus sequence typing (MLST). Majority of the patients were from Bangalore Urban, Karnataka. Among 160 cases 128 (80%) were HIV seropositive, and 32 (20%) were HIV negative. Middle-aged males (36-55 years) were highly affected. There were statistically significant differences in the clinical manifestations, imaging and CSF parameters of HIV coinfected and noninfected cases, whereas limited differences were observed in these parameters in the cases infected with C. neoformans and C. gattii. We identified 80% C. neoformans VNI, 8.75% VNII and 22.5% C. gattii (VGI), 8.75% C. tetragattii (VGIV) among clinical strains. This comprehensive study will contribute toward a better prognosis of CNS cryptococcosis patients during the hospital stay, treatment strategies for HIV coinfected and noninfected cases and will provide the molecular epidemiology of these two pathogenic fungal species in south India, which was unclear in this part of the country.

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.

Direct Antiviral Mechanisms of Interferon-Gamma

Interferon-gamma (IFNG) is a pleiotropic cytokine that modulates both innate and adaptive immune networks; it is the most potent activator of macrophages and a signature cytokine of activated T lymphocytes. Though IFNG is now appreciated to have a multitude of roles in immune modulation and broad-spectrum pathogen defense, it was originally discovered, and named, as a secretory factor that interferes with viral replication. In contrast to the prototypical type I interferons produced by any cells upon viral infection, only specific subsets of immune cells can produce IFNG upon infection or stimulation with antigen or mitogen. Still, virtually all cells can respond to both types of interferons. This makes IFNG a versatile anti-microbial cytokine and also gives it a unique position in the antiviral defense system. The goal of this review is to highlight the direct antiviral mechanisms of IFNG, thereby clarifying its antiviral function in the effective control of viral infections.

Ecoepidemiology of Cryptococcus gattii in Developing Countries

Cryptococcosis is a systemic infection caused by species of the encapsulated yeast Cryptococcus. The disease may occur in immunocompromised and immunocompetent hosts and is acquired by the inhalation of infectious propagules present in the environment. Cryptococcus is distributed in a plethora of ecological niches, such as soil, pigeon droppings, and tree hollows, and each year new reservoirs are discovered, which helps researchers to better understand the epidemiology of the disease. In this review, we describe the ecoepidemiology of the C. gattii species complex focusing on clinical cases and ecological reservoirs in developing countries from different continents. We also discuss some important aspects related to the antifungal susceptibility of different species within the C. gattii species complex and bring new insights on the revised Cryptococcus taxonomy.