Exploring a Rare Pulmonary Coinfection: Cryptococcal Pneumonia and Exophiala dermatitidis in an Immunocompetent Host.

Pulmonary cryptococcosis is becoming increasingly common in immunocompetent hosts, manifesting with variable clinical presentations ranging from asymptomatic colonization to severe pneumonia. Radiological findings are non-specific, such as nodular infiltrates, mass-like lesions, and mediastinal lymphadenopathy. We present a case of a 61-year-old woman with Cryptococcus neoformans pneumonia coinfected with Exophiala dermatitidis, an unusual occurrence in an immunocompetent host and the first of its kind. This coinfection posed significant diagnostic challenges due to the rare occurrence of each individual organism in immunocompetent patients as well as the difficulty of their laboratory diagnosis. Treatment regimens, particularly in coinfections, warrant careful consideration to mitigate mortality risk. This case underscores the importance of comprehensive diagnostic strategies and optimized treatment regimens for rare fungal coinfections in immunocompetent hosts.

Isobavachalcone: a redox antifungal agent impairs the mitochondria protein of Cryptococcus neoformans.

Isobavachalcone (IBC) is a natural small-molecule with various biological activities; however, its inhibitory effects on Cryptococcus neoformans remain unclear. In our study, IBC showed a good antifungal effect. Through in vitro experiments, its minimum inhibitory concentration (MIC) was 0.5-1 µg/mL. It exhibited the same antifungal effect as Amphotericin B in brain and lung infections in in vivo experiments. IBC also showed a synergistic antifungal effect with emodin with lower toxicity, and C. neoformans did not develop drug resistance to IBC. In the mechanistic study, significantly damaged mitochondria of C. neoformans, a significant reduction in mitochondrial membrane potential and adenosine triphosphate (ATP) production, and an increase in hydrogen peroxide [H2O2] caused by IBC were observed using transmission electron microscopy. Through drug affinity-responsive target stability combined with phenotype detection, riboflavin synthases of aconitase and succinate dehydrogenase were screened. Molecular docking, quantitative polymerase chain reaction experiments, target inhibitor and agonist intervention, molecular interaction measurements, and MIC detection of the constructed expression strains revealed that IBC targeted the activity of these two enzymes, interfered by the tricarboxylic acid cycle, inhibited the production of ATP, blocked electron transport, reduced mitochondrial membrane potential, and induced antioxidation imbalance and reactive oxygen species accumulation, thus producing an antifungal effect. Therefore, IBC is a promising lead drug and redox antifungal agent for C. neoformans.

Inbred Mouse Models in Cryptococcus neoformans Research.

Animal models are frequently used as surrogates to understand human disease. In the fungal pathogen Cryptococcus species complex, several variations of a mouse model of disease were developed that recapitulate different aspects of human disease. These mouse models have been implemented using various inbred and outbred mouse backgrounds, many of which have genetic differences that can influence host response and disease outcome. In this review, we will discuss the most commonly used inbred mouse backgrounds in C. neoformans infection models.

Pulmonary Cryptococcosis: A Diagnostic and Management Challenge Case Report.

Cryptococcosis is a fungal infection that may arise in immunocompromised or immunocompetent individuals. This case report seeks to demonstrate the difficulty in diagnosing and treating cryptococcosis based on clinical presentation and radiographic features as together, they mimic other pathological conditions. A 56-year-old female with cirrhosis presented with persistent abdominal pain, dyspnea, vomiting, and diarrhea and was diagnosed with pulmonary cryptococcosis after an initial diagnosis of bacterial pneumonia. With no improvement following antibiotic therapy for suspected bacterial pneumonia, additional imaging was performed with a confirmatory lung biopsy for pulmonary cryptococcosis. The patient initiated antifungal therapy with the anticipation of completing approximately 12 months with follow-up imaging to evaluate improvement. After the patient experienced adverse effects of antifungal therapy and did not achieve significant improvement or recovery in her condition, it was apparent that cryptococcal pneumonia presents both diagnostic and management challenges that must be further explored.

Inhibition of RhoA prevents Cryptococcus neoformans capsule glucuronoxylomannan-stimulated brain endothelial barrier disruption.

Cryptococcus neoformans (Cn) is an opportunistic fungus that causes severe central nervous system (CNS) disease in immunocompromised individuals. Brain parenchyma invasion requires fungal traversal of the blood-brain barrier. In this study, we describe that Cn alters the brain endothelium by activating small GTPase RhoA, causing reorganization of the actin cytoskeleton and tight junction modulation to regulate endothelial barrier permeability. We confirm that the main fungal capsule polysaccharide glucuronoxylomannan is responsible for these alterations. We reveal a therapeutic benefit of RhoA inhibition by CCG-1423 in vivo. RhoA inhibition prolonged survival and reduced fungal burden in a murine model of disseminated cryptococcosis, supporting the therapeutic potential targeting RhoA in the context of cryptococcal infection. We examine the complex virulence of Cn in establishing CNS disease, describing cellular components of the brain endothelium that may serve as molecular targets for future antifungal therapies to alleviate the burden of life-threatening cryptococcal CNS infection.

Temporal trends in antifungal susceptibility of Cryptococcus neoformans isolates from a reference laboratory in the United States, 2011-2021.

BACKGROUND: There are no established clinical breakpoints for antifungal agents against Cryptococcus species; however, epidemiological cut-off values can help distinguish wild-type (WT) isolates without any acquired resistance from non-WT strains, which may harbour resistance mechanisms. PATIENTS/METHODS: We describe the trends of antifungal MICs and percentages of WT C. neoformans species complex (CNSC) isolates processed in our reference laboratory from November 2011 to June 2021. There were only nine isolates in 2011, thus, we included them in the year 2012 for data analysis. Clinical data is also described when available. RESULTS: We identified 632 CNSC, the majority collected from blood (n = 301), cerebrospinal fluid (n = 230), and respiratory (n = 71) sources. The overall percentage of WT isolates for amphotericin B (AMB), 5-flucytosine, and fluconazole was 77%, 98%, and 91%, respectively. We noticed a statistically significant change in the percentage of AMB WT isolates over the years, with 98% of isolates being WT in 2012 compared to 79% in 2021 (p < .01). A similar change was not observed for other antifungal agents. Clinical data was available for 36 patients, primarily non-HIV immunocompromised patients with disseminated cryptococcosis. There were no statistically significant differences in the clinical characteristics and outcomes between patients with WT (58.3%) versus non-WT (41.7%) isolates, but we noticed higher mortality in patients infected with an AMB non-WT CNSC isolate. CONCLUSIONS: We observed an increase in the percentage of AMB non-WT CNSC isolates in the past decade. The clinical implications of this finding warrant further evaluation in larger studies.

A Case of Pulmonary Cryptococcosis Caused by Capsule-Deficient Cryptococcus neoformans.

Cryptococcosis, a fungal infection primarily caused by Cryptococcus neoformans (CN), is a significant concern for immunocompromised individuals. This paper presents a case of a 51-year-old immunocompromised male who initially presented with symptoms suggestive of community-acquired pneumonia but was later diagnosed with pulmonary cryptococcosis caused by capsule-deficient CN. The patient's exposure to construction dust, coupled with his immunocompromised state due to immunosuppressive treatment for psoriatic arthritis, likely contributed to his susceptibility. The unique presentation of the disease, due to the absence of the characteristic thick capsule, presented a diagnostic challenge. A brief review is provided looking at the mechanism, pathogenesis, and implications of capsule deficiency in CN. The case provides an example of one of the many presentations of cryptococcosis, especially in immunocompromised individuals, and highlights the diagnostic complexities of capsule-deficient CN strains.

Inositol pyrophosphate dynamics reveals control of the yeast phosphate starvation program through 1,5-IP8 and the SPX domain of Pho81.

Eukaryotic cells control inorganic phosphate to balance its role as essential macronutrient with its negative bioenergetic impact on reactions liberating phosphate. Phosphate homeostasis depends on the conserved INPHORS signaling pathway that utilizes inositol pyrophosphates and SPX receptor domains. Since cells synthesize various inositol pyrophosphates and SPX domains bind them promiscuously, it is unclear whether a specific inositol pyrophosphate regulates SPX domains in vivo, or whether multiple inositol pyrophosphates act as a pool. In contrast to previous models, which postulated that phosphate starvation is signaled by increased production of the inositol pyrophosphate 1-IP7, we now show that the levels of all detectable inositol pyrophosphates of yeast, 1-IP7, 5-IP7, and 1,5-IP8, strongly decline upon phosphate starvation. Among these, specifically the decline of 1,5-IP8 triggers the transcriptional phosphate starvation response, the PHO pathway. 1,5-IP8 inactivates the cyclin-dependent kinase inhibitor Pho81 through its SPX domain. This stimulates the cyclin-dependent kinase Pho85-Pho80 to phosphorylate the transcription factor Pho4 and repress the PHO pathway. Combining our results with observations from other systems, we propose a unified model where 1,5-IP8 signals cytosolic phosphate abundance to SPX proteins in fungi, plants, and mammals. Its absence triggers starvation responses.

Cryptococcal Meningitis in an Apparent Immunocompetent Host.

Cryptococcal meningitis is a severe fungal infection that primarily affects individuals with compromised immune systems, such as those with the human immunodeficiency virus (HIV) or those undergoing immunosuppressive therapies after organ transplantation. In rare cases, immunocompetent individuals may also be affected by this life-threatening condition. We present the case of a 64-year-old male patient with no known underlying immune deficiency diagnosed with cryptococcal meningitis, who presented with persistent headaches and subjective fevers. Due to the absence of apparent immunosuppressive conditions or identifiable risk factors during evaluation, our suspicion for fungal meningitis was low. However, the diagnosis was confirmed through CSF fluid analysis, leading to the immediate initiation of guideline-directed treatment with amphotericin and fluconazole. This case highlights the importance of considering cryptococcal meningitis in the differential diagnosis of persistent headaches, even in patients without known immune compromise. Early recognition and appropriate management are essential to preventing complications and delays in management and guaranteeing optimal outcomes for all our patients.

Fatal Cryptococcal Meningitis in a Patient With Chronic Lymphocytic Leukemia Treated With Ibrutinib.

According to the latest World Health Organization classification published in 2022, chronic lymphocytic leukemia (CLL) is classified as a low-grade proliferation of clonal B-cells. The Bruton tyrosine kinase (BTK) pathway plays a crucial role in B-cell receptor signaling. Ibrutinib, the first irreversible BTK inhibitor, has been shown to improve the survival of CLL patients with lower toxicity than traditional chemotherapy. Cryptococcosis is an invasive fungal infection that primarily affects individuals with compromised immune systems. We present a case of a 69-year-old male with relapsed CLL who received treatment with ibrutinib and subsequently developed meningeal cryptococcosis, presenting with seizures and fever. A physical exam showed bilateral hypoacusis, but no focal deficits. Cerebral imaging was normal and laboratory results showed a low gamma globulin level and leucopenia with lymphopenia but without neutropenia. The cerebrospinal fluid profile was not inflammatory, opening pressure was normal, the classic India ink test was positive, and fungal cultures grew Cryptococcus neoformans. To complete investigations, HIV testing was negative, and sinus and chest tomography scans showed no anomalies. Treatment consisted of discontinuing ibrutinib and administering anti-fungal therapy with liposomal amphotericin (4 mg/kg/day) in combination with flucytosine (25 mg/kg/day). However, the patient's neurological status declined, and he passed away. This case highlights the potential risk of developing opportunistic infections such as cryptococcal meningitis in CLL patients treated with ibrutinib. It is crucial to consider the patient's immune status when administering ibrutinib and to closely monitor for signs of infection.

Cryptococcosis in domestic and wild animals: A review.

Cryptococcosis is a fungal disease of public health relevance that affects numerous animal species and humans, causing respiratory and neurological impairment. Hence, we conducted a systematic review that included publications from 1975 to 2021 and covered 132 articles that addressed reports of cryptococcosis in domestic and wild animals, its main clinical manifestations, pathological findings, etiology, diagnosis, and therapeutic protocols. We found that the highest number of reports of cryptococcosis is in domestic species, especially cats. Among the wild and/or exotic animals, koalas and ferrets are the most affected, being important carriers of Cryptococcus spp. Pulmonary and neurological involvement is predominant in all species, although nonspecific clinical manifestations have been reported in various species, making clinical suspicion and diagnosis difficult. The countries with the most reports are Australia, the United States, Brazil, and Canada, with C. gattii VGI and VGII standing out. The therapies were based on azoles, amphotericin B, and 5-flucytosine, although there is no standard treatment protocol. Although, several diagnostic methods have been described, in a significant number of reports the diagnosis was made after a necropsy. Professionals are warned about diverse and nonspecific clinical manifestations in different animal species, which underlines the importance of cryptococcosis in the differential diagnosis in clinical practice. Furthermore, it is necessary to encourage the use of laboratory and molecular tools to improve the diagnosis of cryptococcosis. We also emphasize the urgent need for standardized therapeutic protocols to guide veterinary clinicians.

This review compiles studies on cryptococcosis in domestic and wild animals. Most reports occurred in cats and koalas. Pulmonary and neurological involvement was predominant in all affected species, and C. gattii VGI and VGII stood out in the etiology of the disease.

Antifungal evaluation and mechanistic investigations of membrane active short synthetic peptides-based amphiphiles.

The quest for new class of peptide-based antibiotics has steered this research towards the design and synthesis of short sequences possessing modified amphiphilic histidine along with hydrophobic tryptophan residues. The new structural class of dipeptides Trp-His(1-Bn)-OMe/NHBn and tripeptides His(1-Bn)-Trp-His(1-Bn)-OMe/NHBn demonstrated promising antifungal and antibacterial activities with membrane lytic action. The illustration of desirable hydrophilic-lipophilic balance appeared in the dipeptide Trp-His[1-(3,5-di-tert-butylbenzyl)]-NHBn (13d) that produced the most promising antifungal activity with IC50 value of 2.10 µg/mL and MIC = 3.81 µg/mL against C. neoformans and antibacterial activity against E. faecalis and S. aureus with identical IC50 value of 4.40 µg/mL and MIC of 8.0 µg/mL. Peptide 13d did not exhibit cytotoxicity and hemolysis at the MIC value and above. This quintessence amphiphilicity was further corroborated by the mechanistic elucidations, which revealed that, peptide act by utilizing charge and hydrophobicity as the primary characteristic tools. Owing to their fundamental affinity, the negatively charged fungal membrane is enacted upon by the positively charged peptide, whereas the intrinsic hydrophobicity of the peptide allowed penetration into the lipophillic core of the fungal cell membrane. Consequently, the integrity of cell membrane is compromised leading to increased fluidity. The membrane eventually disintegrates thereby creating a hollow pore and appearance of a doughnut into the cell when visualized under SEM. The cell death mechanism and damage to the cell wall and intracellular organelles have been elucidated with the help of flow cytometry, TEM and CLSM studies.

Role of the Heme Activator Protein Complex in the Sexual Development of Cryptococcus neoformans.

The CCAAT-binding heme activator protein (HAP) complex, comprising the DNA-binding heterotrimeric complex Hap2/3/5 and transcriptional activation subunit HapX, is a key regulator of iron homeostasis, mitochondrial functions, and pathogenicity in Cryptococcus neoformans, which causes fatal meningoencephalitis. However, its role in the development of human fungal pathogens remains unclear. To elucidate the role of the HAP complex in C. neoformans development, we constructed hap2Δ, hap3Δ, hap5Δ, and hapXΔ mutants and their complemented congenic MATα H99 and MATa YL99a strains. The HAP complex plays a conserved role in iron utilization and stress responses in cells of both mating types. Deletion of any of the HAP complex components markedly enhances filamentation during bisexual mating. However, the Hap2/3/5 complex, but not HapX, is crucial in repressing pheromone production and cell fusion and is thus a critical repressor of sexual differentiation of C. neoformans. Interestingly, deletion of the heterotrimeric complex transcriptionally regulated both positive and negative regulators in the pheromone-responsive Cpk1 mitogen-activated protein kinase (MAPK) pathway. Chromatin immunoprecipitation-quantitative PCR analysis revealed that the HAP complex physically bound to the CCAAT motif of the CRG1 and GPA2 promoter regions. Notably, the HAP complex was differentially localized depending on the mating type in basal conditions; it was enriched in the nuclei of MATα cells but diffused in the cytoplasm of MATa cells. Interestingly, however, a portion of the HAP complex in both mating types relocalized to the cell membrane during mating. In conclusion, the Hap2/3/5 heterotrimeric complex and HapX play major and minor roles, respectively, in repressing the sexual development of C. neoformans in association with the Cpk1 MAPK pathway. IMPORTANCE Cryptococcus neoformans isolates are of two mating types: MATα strains, which are predominant, and MATa strains, isolated from the sub-Saharan African region, where cryptococcosis is most abundant and severe. Here, we demonstrated the function of the CCAAT-binding HAP complex (Hap2/3/5/X) as a transcriptional repressor of Cpk1 pathway-related genes in cells of both mating types. Deletion of any HAP complex component markedly enhanced filamentation without affecting normal sporulation. In particular, deletion of the DNA-binding HAP complex components (Hap2/3/5), but not HapX, markedly enhanced pheromone production and cell fusion efficiency, validating its repressive role in the early stage of mating in C. neoformans. The HAP complex regulates the expression of both negative and positive mating regulators and is thus crucial for the regulation of the Cpk1 MAPK pathway during mating. This study provides insights into the complex signaling networks governing the sexual differentiation of C. neoformans.

A Case of Cryptococcal Meningitis and Fungemia With Relapse in an HIV-Negative, Non-transplant Patient on Azathioprine Therapy for Mixed Connective Tissue Disorder.

Cryptococcal meningitis typically occurs in immunocompromised patients. Approximately 80% of cryptococcal infections occur in HIV patients. Non-HIV, non-transplant recipient patients are the least numerous population groups affected by cryptococcal infections. While this group includes patients on biologics and corticosteroids, very few cases have been reported in patients on azathioprine. Cryptococcal meningitis requires antifungal therapy, the duration of which varies among different population groups. Inadequate duration of antibiotics among these groups is one of the most common reasons for relapse; therefore, it is crucial to consider patient demographic when determining antifungal duration. Here, we report a 68-year-old male with a history of mixed connective tissue disease on azathioprine for six years, who was admitted to the hospital with worsening lethargy. Several days into admission, the patient developed low-grade fevers. Subsequent blood cultures grew Cryptococcus neoformans. He was started on liposomal amphotericin B. Lumbar puncture (LP) was done, which demonstrated positive cryptococcal antigen, and flucytosine was added to the treatment regimen. Repeat CSF culture demonstrated no fungal organisms. Amphotericin B was discontinued after 20 days of therapy. Following clinical improvement, he was subsequently discharged on oral fluconazole. One week following discharge, the patient was readmitted with worsening fevers and altered mental status. CSF studies demonstrated the growth of Cryptococcus on culture. Liposomal amphotericin B was reinitiated, and fluconazole was continued. Imaging showed hydrocephalus, which worsened despite ventriculoperitoneal shunt. The patient expired following transition to comfort care. In conclusion, cryptococcal meningitis should be considered as a differential in non-HIV, non-transplant patients on azathioprine presenting with fever and worsening lethargy, and 4-6 weeks of induction therapy is required in this patient group to prevent relapse.

Macrophage Mediated Immunomodulation During Cryptococcus Pulmonary Infection.

Macrophages are key cellular components of innate immunity, acting as the first line of defense against pathogens to modulate homeostatic and inflammatory responses. They help clear pathogens and shape the T-cell response through the production of cytokines and chemokines. The facultative intracellular fungal pathogen Cryptococcus neoformans has developed a unique ability to interact with and manipulate host macrophages. These interactions dictate how Cryptococcus infection can remain latent or how dissemination within the host is achieved. In addition, differences in the activities of macrophages have been correlated with differential susceptibilities of hosts to Cryptococcus infection, highlighting the importance of macrophages in determining disease outcomes. There is now abundant information on the interaction between Cryptococcus and macrophages. In this review we discuss recent advances regarding macrophage origin, polarization, activation, and effector functions during Cryptococcus infection. The importance of these strategies in pathogenesis and the potential of immunotherapy for cryptococcosis treatment is also discussed.

Methamphetamine Enhances Cryptococcus neoformans Melanization, Antifungal Resistance, and Pathogenesis in a Murine Model of Drug Administration and Systemic Infection.

Methamphetamine (METH) is a major public health and safety problem in the United States. Chronic METH abuse is associated with a 2-fold-higher risk of HIV infection and, possibly, additional infections, particularly those that enter through the respiratory tract or skin. Cryptococcus neoformans is an encapsulated opportunistic yeast-like fungus that is a relatively frequent cause of meningoencephalitis in immunocompromised patients, especially in individuals with AIDS. C. neoformans melanizes during mammalian infection in a process that presumably uses host-supplied compounds such as catecholamines. l-3,4-Dihydroxyphenylalanine (l-Dopa) is a natural catecholamine that is frequently used to induce melanization in C. neoformans. l-Dopa-melanized cryptococci manifest resistance to radiation, phagocytosis, detergents, and heavy metals. Using a systemic mouse model of infection and in vitro assays to critically assess the impact of METH on C. neoformans melanization and pathogenesis, we demonstrated that METH-treated mice infected with melanized yeast cells showed increased fungal burdens in the blood and brain, exacerbating mortality. Interestingly, analyses of cultures of METH-exposed cryptococci supplemented with l-Dopa revealed that METH accelerates fungal melanization, an event of adaptation to external stimuli that can be advantageous to the fungus during pathogenesis. Our findings provide novel evidence of the impact of METH abuse on host homeostasis and increased permissiveness to opportunistic microorganisms.

Cryptococcal Osteomyelitis in an Immunocompetent Patient.

Cryptococcal osteomyelitis is extremely rare. When cryptococcal infections occur, they are usually caused by Cryptococcus neoformans and involve the lungs or central nervous system in an immunocompromised individual. However, we report a case of osteomyelitis of the right ankle and right elbow due to C. neoformans in a 29-year-old immunocompetent male.

Horse: a potential source of Cryptococcus neoformans and Cryptococcus gattii in Egypt.

BACKGROUND: Cryptococcosis is an opportunistic mycozoonosis of global significance in a wide variety of host species. In equines, cryptococcosis is uncommon, and sporadic cases have been reported with rhinitis, sinusitis, pneumonia, and meningitis. Cryptococcus spp. represents a potential risk for immunosuppressed and healthy persons. In Egypt, epidemiological data on cryptococcal infection in horses are limited. The current study was carried out to investigate the occurrence of Cryptococcus spp. in horses and its possible role in the epidemiology of such disease in Egypt. A total of 223 samples was collected from different localities in Egypt included 183 nasal swabs from horses, 28 nasal swabs from humans, and 12 soil samples. Bacteriological examination and the identification of Cryptococcus spp. were performed. Molecular serotyping of Cryptococcus spp. was determined by multiplex PCR using CNa-70S/A-CNb-49S/A. The virulence genes (LAC1, CAP59, and PLB1) of the identified isolates were detected by PCR. Moreover, sequencing and phylogenetic analysis of the C. gattii gene from horses, humans, and soil isolates found nearby were performed. RESULT: The overall occurrence of Cryptococcus spp. in horses were 9.3, 25, and 10.7% in horses, the soil, and humans, respectively. Molecular serotyping of the Cryptococcus spp. isolates recovered from the nasal passages of horses proved that C. gattii (B), C. neoformans, and two hybrids between C. neoformans (A) and C. gattii (B) were identified. Meanwhile, in case of soil samples, the isolates were identified as C. gattii (B). The human isolates were serotyped as C. gattii in two isolates and C. neoformans in only one isolate. Molecular detection of some virulence genes (LAC1), (CAP59), and (PLB1) were identified in both C. gattii and C. neoformans isolates. The C. gattii gene amplicons of the isolates from horses, humans, and the soil were closely related. CONCLUSION: This study provides the first insights into the Egyptian horse ecology of Cryptococcus species and highlights the role of horses as asymptomatic carriers in disseminating the potentially pathogenic Cryptococcus spp. It also presents the possible risk of cryptococcosis infection in humans.

An Alternative Diagnostic Method for C. neoformans: Preliminary Results of Deep-Learning Based Detection Model.

Cryptococcus neoformans is an opportunistic fungal pathogen with significant medical importance, especially in immunosuppressed patients. It is the causative agent of cryptococcosis. An estimated 220,000 annual cases of cryptococcal meningitis (CM) occur among people with HIV/AIDS globally, resulting in nearly 181,000 deaths. The gold standards for the diagnosis are either direct microscopic identification or fungal cultures. However, these diagnostic methods need special types of equipment and clinical expertise, and relatively low sensitivities have also been reported. This study aims to produce and implement a deep-learning approach to detect C. neoformans in patient samples. Therefore, we adopted the state-of-the-art VGG16 model, which determines the output information from a single image. Images that contain C. neoformans are designated positive, while others are designated negative throughout this section. Model training, validation, testing, and evaluation were conducted using frameworks and libraries. The state-of-the-art VGG16 model produced an accuracy and loss of 86.88% and 0.36203, respectively. Results prove that the deep learning framework VGG16 can be helpful as an alternative diagnostic method for the rapid and accurate identification of the C. neoformans, leading to early diagnosis and subsequent treatment. Further studies should include more and higher quality images to eliminate the limitations of the adopted deep learning model.

The Emergence of Cryptococcemia in COVID-19 Infection: A Case Report.

Cryptococcus neoformans is a fungus that can cause pulmonary, central nervous system, and dermatological infections, especially in an immunocompromised patient. This is a case report of a patient, who was presumptively immunocompetent that developed isolated cryptococcemia while being treated for coronavirus disease 19 (COVID-19) infection. We report a case of a 59-year-old Hispanic man with a past medical history of hypertension, well-controlled diabetes mellitus, and class I obesity who was admitted for severe acute respiratory distress syndrome coronavirus 2 (SARS-COV-2) and subsequently was diagnosed with cryptococcal fungemia. The patient received 21 days of dexamethasone and during this period, blood and fungal cultures grew C. neoformans. The patient was alert and oriented, did not have focal neurological deficits or meningeal irritation signs; nonetheless, a lumbar puncture was attempted, but not successful. He was treated with intravenous amphotericin B for two weeks, followed by oral fluconazole for six weeks. Repeat blood cultures demonstrated clearance and he improved clinically. In conclusion, this case report describes the possibility of an association between the use of dexamethasone in COVID-19 patients and the development of cryptococcal fungemia. In the review of literature, rare case reports worldwide have discussed this topic. This is clinically challenging as the emergence of opportunistic infections in these debilitated hosts can be detrimental. Maintaining a high clinical suspicion for this opportunistic infection while treating COVID-19 patients is necessary to prevent further mortality associated with this pandemic.