Hepatic Disease with Portal Hypertension and Acute Juvenile Paracoccidioidomycosis: A Report of Two Cases and Literature Review

Chylothorax and chylous ascites due to juvenile paracoccidioidomycosis: a case report

Paracoccidioidomycosis (PCM) is a systemic fungal infection caused by Paracoccidioides species. Chylothorax is a rare complication of PCM. A 16-year-old adolescent presented daily fever, lymphadenomegaly, sweating, weight loss, ventilatory-dependent pain, and dysphagia, which confirmed PCM. During treatment, the patient developed chylothorax and chylous ascites. Chronic inflammatory and fibrotic lymphadenopathy may obstruct lymphatic vessels, resulting in the extravasation of lymph into the abdomen or pleural cavities. Chylothorax is one of several complications of PCM and can lead to respiratory insufficiency, even in patients undergoing antifungal therapy.

Updates in Paracoccidioides Biology and Genetic Advances in Fungus Manipulation

The dimorphic fungi of the Paracoccidioides genus are the causative agents of paracoccidioidomycosis (PCM). This disease is endemic in Latin America and primarily affects workers in rural areas. PCM is considered a neglected disease, despite being a disabling disease that has a notable impact on the public health system. Paracoccidioides spp. are thermally dimorphic fungi that present infective mycelia at 25 °C and differentiate into pathogenic yeast forms at 37 °C. This transition involves a series of morphological, structural, and metabolic changes which are essential for their survival inside hosts. As a pathogen, the fungus is subjected to several varieties of stress conditions, including the host immune response, which involves the production of reactive nitrogen and oxygen species, thermal stress due to temperature changes during the transition, pH alterations within phagolysosomes, and hypoxia inside granulomas. Over the years, studies focusing on understanding the establishment and development of PCM have been conducted with several limitations due to the low effectiveness of strategies for the genetic manipulation of Paracoccidioides spp. This review describes the most relevant biological features of Paracoccidioides spp., including aspects of the phylogeny, ecology, stress response, infection, and evasion mechanisms of the fungus. We also discuss the genetic aspects and difficulties of fungal manipulation, and, finally, describe the advances in molecular biology that may be employed in molecular research on this fungus in the future.

Clinical features and genetic background of the sympatric species Paracoccidioides brasiliensis and Paracoccidioides americana

Introduction

The agents of paracoccidioidomycosis, historically identified as Paracoccidioides brasiliensis, are in fact different phylogenetic species. This study aims to evaluate associations between Paracoccidioides phylogenetic species and corresponding clinical data.

Methods

Paracoccidioides strains from INI/Fiocruz patients (1998–2016) were recovered. Socio-demographic, epidemiological, clinical, serological, therapeutic and prognostic data of the patients were collected to evaluate possible associations of these variables with the fungal species identified through partial sequencing of the ADP-ribosylation factor (arf) and the 43-kDa-glycoprotein (gp43) genes.

Results

Fifty-four fungal strains were recovered from 47 patients, most (72.3%) infected in Rio de Janeiro state, Brazil. Forty-one cases were caused by Paracoccidioides brasiliensis and six by Paracoccidioides americana (former PS2). P. brasiliensis was responsible for severe lymph abdominal forms, whereas patients infected with P. americana presented a high rate of adrenal involvement. However, no statistically significant associations were found for all variables studied. P. americana presented 100% reactivity to immunodiffusion, even when tested against antigens from other species, while negative results were observed in 9 (20%) cases caused by P. brasiliensis, despite being tested against a homologous antigen.

Conclusions

P. brasiliensis and P. americana are sympatric and share similar clinical features and habitat, where they may compete for similar hosts.

Paracoccidioidomycosis (PCM) is a severe systemic mycosis caused by different phylogenetic species. According to previous studies, these species could have an impact in PCM clinical features. This study aims to investigate possible associations between Paracoccidioides species and corresponding clinical data. The fungal strains from the patients were recovered, whereas their clinical data were collected to evaluate possible associations of these variables with the fungal species identified through DNA sequencing. Fifty-four fungal strains were recovered from 47 patients, most infected in Rio de Janeiro state, Brazil. Forty-one cases were caused by Paracoccidioides brasiliensis and six by Paracoccidioides americana. P. brasiliensis was responsible for severe clinical forms, and patients infected with P. americana presented a high rate of adrenal involvement. However, no statistically significant associations were found for all variables studied. P. brasiliensis and P. americana share similar clinical features.

Promising New Antifungal Treatment Targeting Chorismate Synthase from Paracoccidioides brasiliensis

Paracoccidioidomycosis (PCM), caused by Paracoccidioides, is a systemic mycosis with granulomatous character and a restricted therapeutic arsenal. The aim of this work was to search for new alternatives to treat largely neglected tropical mycosis, such as PCM. In this context, the enzymes of the shikimate pathway constitute excellent drug targets for conferring selective toxicity because this pathway is absent in humans but essential for the fungus. In this work, we have used a homology model of the chorismate synthase (EC 4.2.3.5) from Paracoccidioides brasiliensis (PbCS) and performed a combination of virtual screening and molecular dynamics testing to identify new potential inhibitors. The best hit, CP1, successfully adhered to pharmacological criteria (adsorption, distribution, metabolism, excretion, and toxicity) and was therefore used in in vitro experiments. Here we demonstrate that CP1 binds with a dissociation constant of 64 ± 1 μM to recombinant chorismate synthase from P. brasiliensis and inhibits enzymatic activity, with a 50% inhibitory concentration (IC₅₀) of 47 ± 5 μM. As expected, CP1 showed no toxicity in three cell lines. On the other hand, CP1 reduced the fungal burden in lungs from treated mice, similar to itraconazole. In addition, histopathological analysis showed that animals treated with CP1 displayed less lung tissue infiltration, fewer yeast cells, and large areas with preserved architecture. Therefore, CP1 was able to control PCM in mice with a lower inflammatory response and is thus a promising candidate and lead structure for the development of drugs useful in PCM treatment.

Paracoccidioidomycosis due to Paracoccidioides brasiliensis S1 plus HIV co-infection

BACKGROUND

Paracoccidioidomycosis (PCM) is one of the most important systemic mycoses in Latin America and the leading fungal cause of mortality in non-immunosuppressed individuals in Brazil. However, HIV/PCM co-infection can increase the clinical severity in these co-infected patients. This co-infection is rarely reported in the literature mainly because of the different epidemiological profiles of these infections. Furthermore, PCM is a neglected and non-notifiable disease, which may underestimate the real importance of this disease. The advent of molecular studies on the species of the genus Paracoccidioides has expanded the knowledge regarding the severity and the clinical spectrum in PCM. In this context, the development of studies to describe the association of the Paracoccidioides phylogenetic cryptic species in vulnerable populations, such as HIV-infected patients, appears relevant.

OBJECTIVE

To describe the clinical, epidemiological, therapeutic and prognostic aspects in HIV/PCM co-infected patients, along with the molecular identification of the Paracoccidioides species involved in these cases.

METHODS

The investigators performed a molecular and clinical retrospective study involving HIV/PCM co-infected patients, from a reference centre for PCM care in the endemic area of Rio de Janeiro, Brazil, from 1998 to 2015. Molecular identification of the fungal strains was done by amplification of partial sequences of arf and gp43 genes.

FINDINGS

Of 89 patients diagnosed with PCM by fungal isolation in the culture, a viable isolate was recovered for molecular analysis from 44 patients. Of these 44 patients, 28 (63.6%) had their serum samples submitted for enzyme immunoassay tests for screening of HIV antibodies, and 5 (17.9%) had a positive result. All cases were considered severe, with a variable clinical presentation, including mixed, acute/subacute clinical forms and a high rate of complications, requiring combination therapy. Paracoccidioides brasiliensis S1 was the species identified in all cases.

CONCLUSIONS

HIV/PCM co-infection can change the natural history of this fungal disease. The authors reinforce the need to include HIV screening diagnostic tests routinely for patients with PCM.