Proteomics-Based Characterization of the Humoral Immune Response in Sporotrichosis: Toward Discovery of Potential Diagnostic and Vaccine Antigens

Background

Sporothrix schenckii and associated species are agents of human and animal sporotrichosis that cause large sapronoses and zoonoses worldwide. Epidemiological surveillance has highlighted an overwhelming occurrence of the highly pathogenic fungus Sporothrix brasiliensis during feline outbreaks, leading to massive transmissions to humans. Early diagnosis of feline sporotrichosis by demonstrating the presence of a surrogate marker of infection can have a key role for selecting appropriate disease control measures and minimizing zoonotic transmission to humans.

Methodology

We explored the presence and diversity of serum antibodies (IgG) specific against Sporothrix antigens in cats with sporotrichosis and evaluated the utility of these antibodies for serodiagnosis. Antigen profiling included protein extracts from the closest known relatives S. brasiliensis and S. schenckii. Enzyme-linked immunosorbent assays and immunoblotting enabled us to characterize the major antigens of feline sporotrichosis from sera from cats with sporotrichosis (n = 49), healthy cats (n = 19), and cats with other diseases (n = 20).

Principal Findings

Enzyme-linked immunosorbent assay-based quantitation of anti-Sporothrix IgG exhibited high sensitivity and specificity in cats with sporotrichosis (area under the curve, 1.0; 95% confidence interval, 0.94–1; P<0.0001) versus controls. The two sets of Sporothrix antigens were remarkably cross-reactive, supporting the hypothesis that antigenic epitopes may be conserved among closely related agents. One-dimensional immunoblotting indicated that 3-carboxymuconate cyclase (a 60-kDa protein in S. brasiliensis and a 70-kDa protein in S. schenckii) is the immunodominant antigen in feline sporotrichosis. Two-dimensional immunoblotting revealed six IgG-reactive isoforms of gp60 in the S. brasiliensis proteome, similar to the humoral response found in human sporotrichosis.

Conclusions

A convergent IgG-response in various hosts (mice, cats, and humans) has important implications for our understanding of the coevolution of Sporothrix and its warm-blooded hosts. We propose that 3-carboxymuconate cyclase has potential for the serological diagnosis of sporotrichosis and as target for the development of an effective multi-species vaccine against sporotrichosis in animals and humans.     

Squamous cell carcinoma subsequent to scarring caused by sporotrichosis: A case report

BackgroundSporotrichosis is a fungal disease caused by the Sporothrix schenckii species complex. It is usually acquired by trauma with plants. Lymphatic-cutaneous is the most common clinical manifestation.Case reportThe present case describes the development of an epidermoid carcinoma as a late complication on a long evolution sporotrichosis scar. During a period of 50 years, the patient had lesions in the right hand. Sporotrichosis was diagnosed and treated with potassium iodide. Eleven years after the healing of the lesions, a squamous cell carcinoma on the scar of this mycosis was diagnosed.ConclusionsThe chronic sporotrichosis injury was probably the cause of the tumor developed on the scar.     

Diagnosis and Treatment of Lymphocutaneous Sporotrichosis: What Are the Options?

Lymphocutaneous sporotrichosis is the most common clinical form of cutaneous sporotrichosis. Caused by a complex of dimorphic fungi called Sporothrix schenckii complex, it is an occupational disease, present especially in tropical and subtropical areas, and has been reported in all continents. Diagnosis is established by isolation of the causative agent. Therapy of choice for lymphocutaneous sporotrichosis is itraconazole, and in developing countries, potassium iodide solution. In general, the lymphocutaneous form is considered a mild benign form of the disease, and the majority of cases respond well to treatment in about 3–4 months of therapy. In this paper, we have made a general review of the disease, especially of the epidemiology, clinical features and diagnosis of the lymphocutaneous form, as well as a brief analysis of the advantages and disadvantages of diverse treatments.     

The spread of cat-transmitted sporotrichosis due to Sporothrix brasiliensis in Brazil towards the Northeast region

BackgroundSporotrichosis is a worldwide subcutaneous mycosis caused by Sporothrix spp. In the past, this infection was associated with armadillo hunting, horticulturists, miners, and gardeners, being considered an implantation mycosis acquired by plant debris injury. Nevertheless, since the late nineties, it has been considered a zoonotic disease in Brazil. Here we report a case series of 121 patients with cat-transmitted sporotrichosis seen in Northeast Brazil.Methodology/Principal findingsPatient’s demographic, clinical data, and length of treatment were recorded. In addition, a mycological examination and further PCR confirmation of species identification were performed. One hundred and twenty two patients were diagnosed with subcutaneous sporotrichosis from October 2016 to December 2019, while PCR revealed that 71 of them were due to S. brasiliensis. The majority of the individuals were female (n = 86; 70.5%). Patient’s age ranged from 5 to 87 years old. The clinical forms found were lymphocutaneous (58.2%) and fixed cutaneous (39.4%). Interestingly, 115 patients reported previous contact with cats diagnosed with sporotrichosis. Patients were successfully treated with itraconazole and potassium iodide.Conclusions/SignificanceOur study adds important contributions for the investigation of the spread of cat-transmitted subcutaneous sporotrichosis in Brazil, specifically towards the Northeast region of a continental-size country. It will also help clinicians to be aware of the existence and importance to accurately diagnose sporotrichosis and treat patients with this infectious disease in the lowest income region of Brazil.     

Sporotrichosis in Rio de Janeiro,Brazil: Sporothrix brasiliensis Is Associated with Atypical Clinical Presentations

Background

There have been several recent changes in the taxonomy of Sporothrix schenckii as well as new observations regarding the clinical aspects of sporotrichosis. In this study, we determined the identification of the Sporothrix species associated with both classic and unusual clinical aspects of sporotrichosis observed in the endemic area of sporotrichosis in Rio de Janeiro, Brazil.

Methodology/Principal Findings

To verify whether S. brasiliensis is associated with clinical manifestations of sporotrichosis, a cross-sectional study was performed in which Sporothrix isolates from 50 patients with different clinical manifestations were analyzed and their isolates were studied by phenotypic and genotypic methods. Data from these patients revealed a distinct clinical picture and therapeutic response in infections caused by Sporothrix brasiliensis (n = 45) compared to patients with S. schenckii sensu stricto (n = 5). S. brasiliensis was associated with disseminated cutaneous infection without underlying disease, hypersensitivity reactions, and mucosal infection, whereas patients with S. schenckii presented with less severe and more often localized disease, similar to the majority of previously described sporotrichosis cases. Interestingly, S. brasiliensis-infected patients overall required shorter durations of itraconazole (median 16 weeks) compared to the individuals with S. schenckii (median 24 weeks).

Conclusions/Significance

These findings suggest that Sporothrix species are linked to different clinical manifestations of sporotrichosis and that S. brasiliensis is effectively treated with oral itraconazole.     

Diagnostic performance of mycologic and serologic methods in a cohort of patients with suspected sporotrichosis

BackgroundThe gold standard for the sporotrichosis diagnosis is culture; however, serologic approaches have been recently implemented to aid in the sporotrichosis diagnosis. Nevertheless, the clinical consequences of the introduction of serologic tests are poorly addressed.AimsTo correlate the results of culture and serology of patients with suspected sporotrichosis.MethodsA retrospective study of 198 patients with suspected sporotrichosis was conducted. Information about culture isolation of Sporothrix from clinical samples and antibody detection by an enzyme-linked immunosorbent assay (ELISA) were obtained from the medical records of the patients.ResultsPositive culture and antibody detection was observed in the samples of 84 patients (42.4%). Forty-one samples (20.7%) showed negative results with both techniques and divergent results were obtained in the samples of 73 patients (36.9%). False negative results in the ELISA were observed with 23 patients (31.5%), 78.3% of them with less than 30 days of infection (p = 0.0045). Among the initial false positive ELISA in the sera of 50 patients, four samples in culture yielded the growth of Sporothrix, and 27 improved with itraconazole. At the end of follow-up, a diagnosis of proven or probable sporotrichosis was established in 139 patients, and possible sporotrichosis in 11 patients. The treatment of the patients with probable sporotrichosis with antifungal drugs resulted in clinical cure for these individuals.ConclusionsThese two techniques are complementary in the diagnosis of sporotrichosis, making diagnosis and clinical decision more precise.     

Variation in Genotype and Higher Virulence of a Strain of <Emphasis Type="Italic">Sporothrix schenckii</Emphasis> Causing Disseminated Cutaneous Sporotrichosis

Sporotrichosis is usually a localized, lymphocutaneous disease, but its disseminated type was rarely reported. The main objective of this study was to identify specific DNA sequence variation and virulence of a strain of Sporothrix schenckii isolated from the lesion of disseminated cutaneous sporotrichosis. We confirmed this strain to be S. schenckii by^® tubulin and chitin synthase gene sequence analysis in addition to the routine mycological and partial ITS and NTS sequencing. We found a 10-bp deletion in the ribosomal NTS region of this strain, in reference to the sequence of control strains isolated from fixed cutaneous sporotrichosis. After inoculated into immunosuppressed mice, this strain caused more extensive system involvement and showed stronger virulence than the control strain isolated from a fixed cutaneous sporotrichosis. Our study thus suggests that different clinical manifestation of sporotrichosis may be associated with variation in genotype and virulence of the strain, independent of effects due to the immune status of the host.     

Successful Treatment of Canine Sporotrichosis with Terbinafine: Case Reports and Literature Review

Sporotrichosis occurs worldwide, and the metropolitan region of Rio de Janeiro, Brazil, is a main endemic area, with a large number of human and animal cases in the last 19 years. This mycosis is more frequently described in cats rather than in dogs. There are a limited number of oral antifungal agents for the treatment of sporotrichosis in animals. In this context, the effectiveness of terbinafine in the treatment of sporotrichosis in humans, as well as the promising results of in vitro susceptibility tests, inspired us to use this drug in the therapy of this mycosis in dogs. We reported for the first time the use of terbinafine in the treatment of two dogs with sporotrichosis caused by Sporothrix brasiliensis. Moreover, we provided an overview of therapeutic features of canine sporotrichosis cases reported since the 1960s. One of the dogs presented the fixed cutaneous form of the disease, while the other patient presented hyperemia of the nasal mucosa and respiratory signs only. Terbinafine showed high antifungal activity in vitro against the canine Sporothrix isolates. The dogs were successfully treated with terbinafine, with remission of all clinical signs initially presented. The current reports indicate that this drug can emerge as a therapeutic option for canine sporotrichosis.     

Sporotrichosis in sub-himalayan India

Sporotrichosis is endemic in the Sub-Himalayan belt, which ranges from the northern to the north-eastern Indian subcontinent. Similar to many parts of the developing world, sporotrichosis is commonly recognized clinically in this region however consolidated epidemiological data is lacking. We report epidemiological, clinical and microbiological data from a hundred culture positive cases of sporotrichosis. Out of 305 clinically suspicious cases of sporotrichosis, a total of 100 isolates were identified as Sporothrix schenckii species complex (S. schenckii) on culture. Out of the culture proven cases 71% of the cases presented with lymphocutaneous type of lesions while 28% had fixed localized type and 1% had disseminated sporotrichosis. Presentation with lesions on hands was most frequently seen in 32% with arm (23%) and face (21%) in that sequence. The male to female ratio was 1∶1.27. Age ranged from 1 ½ years to 88 years. Mean age was 43.25 years. Disease was predominantly seen in the fourth to sixth decade of life with 58% cases between 31 and 60 years of age. Since the first report from the region there has been a steady rise in the number of cases of sporotrichosis. Seasonal trends reveal that most of the patients visited for consultation in the beginning of the year between March and April. This is the first study, from the most endemic region of the Sub-Himalayan belt, to delve into epidemiological and clinical details of such a large number of culture proven cases over a period of more than eighteen years which would help in the understanding of the local disease pattern of sporotrichosis.     

Acute dacryocystitis: another clinical manifestation of sporotrichosis

Sporotrichosis associated with exposure to domestic cats is hyperendemic in Rio de Janeiro, Brazil. A review of the clinical records at our institute revealed four patients with clinical signs of dacryocystitis and a positive conjunctival culture for Sporothrix who were diagnosed with Sporothrix dacryocystitis. Three patients were children (< 13 years of age) and one patient was an adult. Two patients reported contact with a cat that had sporotrichosis. Dacryocystitis was associated with nodular, ulcerated lesions on the face of one patient and with granulomatous conjunctivitis in two patients; however, this condition manifested as an isolated disease in another patient. All of the patients were cured of the fungal infections, but three patients had chronic dacryocystitis and one patient developed a cutaneous fistula. Sporotrichosis is usually a benign disease, but may cause severe complications when the eye and the adnexa are affected. Physicians, especially ophthalmologists in endemic areas, should be aware of the ophthalmological manifestations and complications of sporotrichosis.     

Progress in Brucella vaccine development

Brucella spp. are zoonotic, facultative intracellular pathogens, which cause animal and human disease. Animal disease results in abortion of fetuses; in humans, it manifests flu-like symptoms with an undulant fever, with osteoarthritis as a common complication of infection. Antibiotic regimens for human brucellosis patients may last several months and are not always completely effective. While there are no vaccines for humans, several licensed live Brucella vaccines are available for use in livestock. The performance of these animal vaccines is dependent upon the host species, dose, and route of immunization. Newly engineered live vaccines, lacking well-defined virulence factors, retain low residual virulence, are highly protective, and may someday replace currently used animal vaccines. These also have possible human applications. Moreover, due to their enhanced safety and efficacy in animal models, subunit vaccines for brucellosis show great promise for their application in livestock and humans. This review summarizes the progress of brucellosis vaccine development and presents an overview of candidate vaccines.     

An unhealing wound and subcutaneous nodules due to Sporothrix globosa after a cat bite

A 51-year-old man with 3-month unhealing cat bite wound was diagnosed with sporotrichosis, a subacute-to-chronic infection caused by the worldwide endemic, dimorphic fungus Sporothrix globosa. The case would help clinicians to raise awareness of human sporotrichosis due to cat bites, which remains rare and is likely to be underrecognized and misdiagnosed.     

Sporotrichosis in Children: an Update

Sporotrichosis, a disease caused by the saprophytic, dimorphic fungus Sporothrix schenckii, is currently diagnosed worldwide, especially in some tropical and subtropical areas. The infection usually occurs after traumatic inoculation of soil, plants, and organic matter containing the fungus. Certain activities, such as floriculture, agriculture, mining, and wood exploitation, and zoonotic transmission are associated with the mycosis. In humans, the disease is limited to skin, subcutaneous tissue, and the proximal lymphatic. It occurs commonly as lymphocutaneous or fixed lesions predominantly affect the upper limbs and face, the latter location is frequent in children. However, sporotrichosis in children is uncommonly seen. Data about the disease on this specific group of patients is scanty. The gold standard for diagnosis is culture. Nevertheless, there are other recently added methods (serological, histopathological, and molecular) useful for an accurate diagnosis. Itraconazole is the first choice of treatment for sporotrichosis; however, potassium iodide is also an effective option, mainly in children.     

Chronic pulmonary sporotrichosis

We report a case of chronic human pulmonary sporotrichosis which was not associated with superficial manifestations involving the skin or lymph nodes. As it is difficult to verify an etiology, it is possible that some undiagnosed pulmonary granulomas could represent pulmonary sporotrichosis of the chronic type. These may have been treated for other diseases, such as a mycobacterial infection as in this case. Since the immunodiffusion test is a simple procedure and is almost always positive in chronic disease, its greater utilization should help in defining this disease more frequently. The skin test, agglutination test and culture are variably useful as documented in the literature.Sporotrichosis is a common mycotic infection which is usually confined to the skin and superficial lymph nodes. In disseminated disease, the lung is very rarely involved. Pulmonary sporotrichosis then represents a second form of primary infection though less common than the lymphocutaneous disease. Scott et al. (18) reported two cases of pulmonary sporotrichosis. Ridgeway et al. (15) at about the same time reviewed the previously reported cases up to 1962 and concluded that 12 of the cases could be accepted as sporotrichosis and added two cases of their own. Subsequently, Siegrist & Ferrington (20) and Trevathan & Phillips (23) each reported a case. Presently, approximately 50 cases have been reported in the United States (1–10, 12, 13, 16). Chronic and acute involvement have been delineated by Ridgeway et al. (15) It is believed that the following case represents one of primary pulmonary sporotrichosis of the chronic type without manifest involvement of other organs.     

Disseminated sporotrichosis with immune reconstitution inflammatory syndrome in an HIV patient: Case report and review of the literature

BackgroundSporotrichosis has been occurring as outbreaks in Brazil, reaching epidemic levels in some regions. Zoonotic transmission is the main route to acquire Sporothrix.Case reportWe describe a case of disseminated sporotrichosis caused by Sporothrix brasiliensis in an HIV/AIDS patient, with the presentation of immune reconstitution inflammatory syndrome (IRIS).ConclusionsThis case reinforces that sporotrichosis should always be suspected in patients with IRIS from endemic regions, even in patients without the typical cutaneous lesions of this mycosis.     

WHO/Health Canada meeting on regulatory considerations for evaluation and licensing of new meningococcal Group B vaccines,Ottawa, Canada, 3–4 October 2011

Serogroup B Neisseria meningitides (MenB) is a significant cause of endemic and epidemic outbreaks of the disease worldwide. Although polysaccharide and conjugate vaccines are available against other meningococcal serogroups, the poor immunogenicity of MenB polysaccharide has led to the development of protein-based vaccines. However, the diversity and antigenic variability of MenB strains has been a major challenge. Recently a new generation of MenB vaccines that contain conserved antigens has been developed to provide broader coverage and they are in an advanced stage of development and regulatory consideration. In October 2011, the World Health Organization and Health Canada jointly organized a consultation on regulatory considerations for the evaluation and licensing of new MenB vaccines. The aim was to seek consensus on key regulatory issues relevant to the evaluation of candidate MenB vaccines and on approaches to the standardisation of in vitro assays used in the evaluation process. Participants agreed that functional antibodies as measured in the Serum Bactericidal Activity (SBA) assay could be used to evaluate MenB vaccine efficacy and ways of improving assay standardization proposed. Approaches to bridging SBA data to large collections of strains in order to give an indication of the prospective breadth of vaccine coverage were discussed.     

Phylogenetic Analysis Reveals a High Prevalence of Sporothrix brasiliensis in Feline Sporotrichosis Outbreaks

Sporothrix schenckii, previously assumed to be the sole agent of human and animal sporotrichosis, is in fact a species complex. Recently recognized taxa include S. brasiliensis, S. globosa, S. mexicana, and S. luriei, in addition to S. schenckii sensu stricto. Over the last decades, large epidemics of sporotrichosis occurred in Brazil due to zoonotic transmission, and cats were pointed out as key susceptible hosts. In order to understand the eco-epidemiology of feline sporotrichosis and its role in human sporotrichosis a survey was conducted among symptomatic cats. Prevalence and phylogenetic relationships among feline Sporothrix species were investigated by reconstructing their phylogenetic origin using the calmodulin (CAL) and the translation elongation factor-1 alpha (EF1α) loci in strains originated from Rio de Janeiro (RJ, n = 15), Rio Grande do Sul (RS, n = 10), Paraná (PR, n = 4), São Paulo (SP, n = 3) and Minas Gerais (MG, n = 1). Our results showed that S. brasiliensis is highly prevalent among cats (96.9%) with sporotrichosis, while S. schenckii was identified only once. The genotype of Sporothrix from cats was found identical to S. brasiliensis from human sources confirming that the disease is transmitted by cats. Sporothrix brasiliensis presented low genetic diversity compared to its sister taxon S. schenckii. No evidence of recombination in S. brasiliensis was found by split decomposition or PHI-test analysis, suggesting that S. brasiliensis is a clonal species. Strains recovered in states SP, MG and PR share the genotype of the RJ outbreak, different from the RS clone. The occurrence of separate genotypes among strains indicated that the Brazilian S. brasiliensis epidemic has at least two distinct sources. We suggest that cats represent a major host and the main source of cat and human S. brasiliensis infections in Brazil.