Search

The ability of yeast cells of Histoplasma capsulatum to attach and agglutinate human erythrocytes has been described. This is the first report involving these yeasts in the hemagglutination phenomenon. Results revealed that the yeast cells were able to bind to erythrocytes irrespective of blood groups and to agglutinate them when a high density of yeast cells was used. Assays on the inhibition of yeast attachment to erythrocytes were also performed, using sugar-treated yeast cells. Results indicate that galactose (Gal), mainly the β-anomer, specially inhibited yeast attachment. Disaccharides (Gal-derivatives) and glycosaminoglycans containing Gal residues, mainly chondroitin sulfate C, promote this type of inhibition. In addition, preliminary data of inhibition assays also involved a probable ionic strength driven mechanism mediated by sialic acid and heparan sulfate, suggesting that yeast binding to erythrocytes could be associated with negative charges of both molecules. [ABSTRACT FROM AUTHOR]

Crude histoplasmin and a polysaccharide-protein complex (PPC-histo) antigens obtained from culture filtrates of Histoplasma capsulatum were analyzed by single and tandem two-dimensional immunoelectrophoresis (TD-IEP) using a rabbit hyperimmune anti-histoplasmin polyvalent serum. Single TD-IEP showed 14 arc precipitates for histoplasmin. Continuity of arcs 2, 6, and 7, and 9 and 10 was observed, suggesting a different polymeric configuration of the same antigen. This was also confirmed in tandem TD-IEP of histoplasmin with homologous (PPC-histo) and heterologous PPC's from Blastomyces dermatitidis, Paracoccidioides brasiliensis and Coccidioides immitis. Tandem TD-IEP of histoplasmin and PPC-histo displayed a similar antigenic pattern to histoplasmin alone, being arcs 1 and 3 more evident and apparently present only in histoplasmin and PPC-histo. Tandem TD-IEP showed common antigens among the other heterologous fungal purified antigens, and seems useful to observe the multiplicity of antigens present in fungal preparations and to identify those precipitates (arcs 1 and 3) that are predominant in the purified preparation. [ABSTRACT FROM AUTHOR]

Viral warts represent a common cutaneous manifestation of the human papillomavirus infection, affecting mainly hands and feet. Treatment may include cryosurgery or keratolitic agents. A group of patients are resistant to these treatments and require second line management. We report a case of persistent plantar warts, healing with intralesional candidin therapy. [ABSTRACT FROM AUTHOR]

Airborne fungi are widely distributed in the environment and originate from various sources like soil, plants, decaying organic matter, and even indoor environments. Exposure to airborne fungal spores can cause allergic reactions, asthma, and respiratory infections. Certain fungi can cause serious infections, particularly in individuals with weakened immune systems. An aerobiological study was conducted to detect airborne fungi using metagenomics in three areas of Mexico City, each representing different degrees of urbanization, during the dry and rainy seasons of 2017. Seasonality showed a significant role in the composition of airborne fungi. Ascomycota predominated in the three areas sampled during dry and rainy seasons, with the genera Cladosporium and Penicillium presenting the highest relative abundances across seasons. The Agaromycetes showed an increase during the rainy season. Regarding the areas, the north and center sites showed similar meteorological conditions and fungal community composition patterns. According to the Shannon and Simpson indices, the south area showed a greater species diversity during the dry season. These insights into the interactions between urbanization, seasonality, and airborne microbial communities could contribute to more effective urban management, reduced health risks, and the promotion of sustainable development.

In Mexico, Triatoma pallidipennis is a major vector of Trypanosoma cruzi, the causative agent of Chagas disease. Current efforts are focused on developing attractants to control these vectors, using volatile substances derived from vertebrate hosts or compounds known to attract hematophagous insects. However, the efficacy of these compounds in attracting parasite-infected triatomines remains to be evaluated. In this study, we assessed the attractant activity of octenol (1-octen-3-ol), nonanal and a mixture of odorants consisting of ammonium hydroxide, lactic acid and hexanoic acid (in a ratio of 1:0.2:0.4 respectively), at concentrations of 1, 10 and 100 ng on the N3, N4 and N5 nymphal stages of T. pallidipennis, both infected and non-infected with T. cruzi. We also evaluated the synergistic effect of the most effective compounds and doses. All experiments were performed in a laboratory using a Y-type glass olfactometer. We found that both infected and non-infected N3 and N4 nymphs were attracted to low doses of octenol, nonanal and the odorant mixture. Particularly noteworthy was the synergistic effect observed between the odorant mixture and nonanal, which significantly increased attraction of T. cruzi-infected individuals. These findings contribute to the development of baited traps utilising these compounds for monitoring triatomines in epidemiological studies or for mass trapping to control these vectors., (© 2024 The Author(s). Medical and Veterinary Entomology published by John Wiley & Sons Ltd on behalf of Royal Entomological Society.)

In this study, molecular typing using Randomly Amplified Polymorphic DNA (RAPD-PCR) was conducted on 16 original isolates of Metarhizium acridum obtained from locusts ( Schistocerca piceifrons ssp. piceifrons .) in Mexico (MX). The analysis included reference strains of the genus Metarhizium sourced from various geographical regions. The isolates were identified by phenotypic (macro and micromorphology) and genotypic methods (RAPD-PCR and Amplified Fragment Length Polymorphisms (AFLP), through a multidimensional analysis of principal coordinates (PCoA) and a minimum spanning network (MST). Subsequently, Sequences-Characterized Amplified Region (SCAR) markers were developed for the molecular detection of M. acridum , these markers were chosen from polymorphic patterns obtained with 14 primers via RAPD-PCR. Phenotypic and genotypic characterization identified the MX isolates as M. acridum . Of all the polymorphic patterns obtained, only OPA04 and OPA05 were chosen, which presented species-specific bands for M. acridum , and further utilized to create SCAR markers through cloning and sequencing of the specific bands. The specificity of these two markers was confirmed via Southern hybridization. The SCAR markers (Ma-160 OPA-05 and Ma-151 OPA-04 ) exhibit remarkable sensitivity, detecting down to less than 0.1 ng, as well as high specificity, as evidenced by their inability to cross-amplify or generate amplification with DNAs from other strains of Metarhizium (as Metarhizium anisopliae ) or different genera of entomopathogenic fungi ( Cordyceps fumosorosea and Akanthomyces lecanii ). These SCAR markers yield readily detectable results, showcasing high reproducibility. They serve as a valuable tool, especially in field applications.

Infectious keratitis and sclerokeratitis caused by filamentous fungi prevail in agricultural regions with tropical and subtropical climates and are related mostly to mild abrasive corneal trauma especially after vegetable matter related injury. Biotechnological advances have introduced biological control agents in agriculture such as fungal-based biocontrol agents that use Beauveria and Metarhizium species as bioinsecticides. Keratitis and sclerokeratitis are the most frequent pathologies associated to Beauveria and Metarhizium infection that are the main entomopathogenic fungi used in biological control, although other clinical cases such as sinus, skin lesions, and disseminated infections have been reported. Search of publications was carried out using the databases: Scopus, Pubmed, ScienceDirect, MedLine Scielo. A total of 30 articles were retrieved from 1984 - 2021. From these, 17 keratitis and one sclerokeratitis clinical cases were related to Beauveria infection, while Metarhizium was linked to 13 keratitis cases and two sclerokeratitis clinical cases. Female sex predominated in both Metarhizium and Beauveria clinical cases, there was no significant difference in sclerokeratitis / keratitis by sex. Contact lenses use was a factor reported in 66.6% cases of infection with Metarhizium and 22.2% with Beauveria. The review of clinical cases of keratitis and sclerokeratitis related to Beauveria and Metarhizium suggests the need to consider entomopathogenic fungi in ocular pathologies and the risk that imply the misuse of contact lenses and agricultural/gardening activities., Competing Interests: Declaration of competing interest No potential conflict of interest has been reported by the authors. All authors have reviewed and approved the manuscript, and it has not been previously published nor being considered for publication elsewhere., (Copyright © 2022 SFMM. Published by Elsevier Masson SAS. All rights reserved.)

Sporotrichosis is an endemic mycosis caused by the species of the Sporothrix genus, and it is considered one of the most frequent subcutaneous mycoses in Mexico. This mycosis has become a relevant fungal infection in the last two decades. Today, much is known of its epidemiology and distribution, and its taxonomy has undergone revisions. New clinical species have been identified and classified through molecular tools, and they now include Sporothrix schenckii sensu stricto, Sporothrix brasiliensis, Sporothrix globosa, and Sporothrix luriei. In this article, we present a systematic review of sporotrichosis in Mexico that analyzes its epidemiology, geographic distribution, and diagnosis. The results show that the most common clinical presentation of sporotrichosis in Mexico is the lymphocutaneous form, with a higher incidence in the 0-15 age range, mainly in males, and for which trauma with plants is the most frequent source of infection. In Mexico, the laboratory diagnosis of sporotrichosis is mainly carried out using conventional methods, but in recent years, several researchers have used molecular methods to identify the Sporothrix species. The treatment of choice depends mainly on the clinical form of the disease, the host's immunological status, and the species of Sporothrix involved. Despite the significance of this mycosis in Mexico, public information about sporotrichosis is scarce, and it is not considered reportable according to Mexico's epidemiological national system, the "Sistema Nacional de Vigilancia Epidemiológica." Due to the lack of data in Mexico regarding the epidemiology of this disease, we present a systematic review of sporotrichosis in Mexico, between 1914 and 2019, that analyzes its epidemiology, geographic distribution, and diagnosis.

Meccus pallidipennis Stål is a vector for Chagas disease. The extensive use of pyrethroid insecticides to control triatomines in Mexico has resulted in the development of resistant populations. As an alternative control approach, the effects on M. pallidipennis eggs of two entomopathogenic fungi, Isaria fumosorosea Wize (Hypocreales: Cordycipitaceae) EH-511/3 and Metarhizium anisopliae (Metschn.) Sorokin (Hypocreales: Clavicipitaceae) EH-473/4, were examined. Egg mortality was estimated 1 mo after egg infection, based on hyphal growth and unsuccessful hatching as proxies for infection and death. Sporulation and conidial production rates were also recorded. Mortality rates caused by I. fumosorosea and Me. anisopliae were 92% ± 3.1 and 88% ± 3.7, respectively. Sporulation rate and conidial production were greater in I. fumosorosea than in Me. anisopliae. Transmission electron microscopy revealed hyphal penetration by both fungal species and damage to embryonic epidermal and cuticular cells. Our results demonstrated that I. fumosorosea and Me. anisopliae are promising candidates for controlling M. pallidipennis eggs and offer alternatives to control the transmission of Chagas disease under natural conditions.

Sporotrichosis is a chronic subcutaneous mycosis caused by the Sporothrix schenckii species complex and it is considered an emerging opportunistic infection in countries with tropical and subtropical climates. The host's immune response has a main role in the development of this disease. However, it is unknown the features of the memory cellular immune response that could protect against the infection. Our results show that i.d. immunization in the ears of mice with inactivated S. schenckii conidia (iC) combined with the cholera toxin (CT) induces a cellular immune response mediated by circulating memory CD4 + T cells, which mainly produce interleukin 17 (IL-17). These cells mediate a strong delayed-type hypersensitivity (DTH) reaction. Systemic and local protection against S. schenckii was mediated by circulating CD4 + T cells. In contrast, the infection induces a potent immune response in the skin mediated by CD4 + T cells, which have an effector phenotype that preferentially produce interferon gamma (IFN-γ) and mediate a transitory DTH reaction. Our findings prove the potential value of the CT as a potent skin adjuvant when combined with fungal antigens, and they also have important implications for our better understanding of the differences between the memory immune response induced by the skin immunization and those induced by the infection; this knowledge enhances our understanding of how a protective immune response against a S. schenckii infection is developed.

Objectives: Disseminated histoplasmosis is an AIDS-defining illness. Histoplasmosis is commonly misdiagnosed as tuberculosis. Nigeria has the second highest number of people living with HIV/AIDS in Africa. The present study was carried out to investigate the prevalence of skin sensitivity amongst Nigerians to histoplasmin., Design: A cross-sectional study was conducted in six centres across five geopolitical zones of Nigeria., Methods: We recruited both healthy non-HIV and HIV-positive adults with CD4 count ≥ 350 cells/mm3 regardless of their ART status from March to May 2017. Skin tests were performed intradermally; induration ≥5 mm were considered to be histoplasmin positive., Results: 750 participants were recruited from Lagos (n = 52), Yola (n = 156), Ilorin (n = 125), Calabar (n = 120), Ibadan (n = 202) and Benin (n = 95). 467 (62.3%) were HIV negative, 247 (32.9%) were HIV positive and 36 (4.8%) did not know their HIV status. A total of 32/735 (4.4%) participants had a positive skin test. Study centre (p<0.001), education (p = 0.002) and age (p = 0.005) appeared to be significantly associated with positive skin reactivity at the 0.5% significance level, while sex (p = 0.031) and occupation (p = 0.031) would have been significant at the 5% significance level. Males had a higher rate of reactivity than females (p = 0.031, 7% vs 3%). The highest positive rates were recorded from Benin City (13/86 (15%)) and Calabar (7/120 (6%)) and no positives were recorded in Lagos (p<0.001). HIV status was not statistically significant (p = 0.70)., Conclusion: Histoplasmosis diagnostics should be included in the Nigerian HIV guidelines. Epidemiological vigilance of progressive disseminated histoplasmosis should be considered by local health authorities.

Sporotrichosis is the most common implantation mycosis caused by several species of the Sporothrix schenckii complex. The gold standard for diagnosis is concerned with the isolation of the fungus; although, fresh examinations, staining, and biopsies are also helpful for this purpose. The sporotrichin is an antigenic complex comprised of a peptide-rhamnomannan, which is relevant with respect to pathogenic fungi; it is primarily used for serological and skin testing. We present a study regarding the use of sporotrichin as a diagnostic aid for cutaneous sporotrichosis. Furthermore, 138 cases with suspicion of sporotrichosis were included, 55 of which were proven through cultures. Moreover, out of these 55 cases, 52 (94.5%) tested positive for sporotrichin, while the negative cases corresponded to the disseminated cutaneous forms. We observed a sensitivity of 94.5% and a specificity of 95.2%. We consider that the use of sporotrichin as a skin test helps us as an auxiliary diagnosis before a positive sample culture.

Isaria fumosorosea (formerly Paecilomyces fumosoroseus) is an entomopathogenic fungus that has been proposed as a low risk environmental alternative to the use of chemical insecticides to control agricultural pests and disease vectors. Although there are some mycoinsecticides already being marketed in many countries, not all their biosafety protocols have been published. The acute dermal toxicity test in an animal model is one in a series of biosafety protocols that must be developed, in order to provide information on health hazards, while taking into consideration the periods that the workers are in direct contact with the microbial agent when applied for the control of pests. For this test, we used I. fumosorosea monospore culture EH-506/3, isolated in Mexico from the Bemisia tabaci whitefly, applying a dose of 2 g/kg of animal body weight, on the shaved skin of 16 New Zealand rabbits, with an exposure time of 24 h. Clinical observations were conducted to evaluate the presence of erythema, edema and other alterations in the skin, as well as the behavior and health of the animals, for a period of 14 days. None of the rabbits showed clinical signs of any disease and their body weight corresponded to the expected weight for a healthy rabbit. The test showed no inflammatory reactions in the skin, supporting the safety of a single dose of this fungus in dermal exposure. Therefore, these data support the safety of I. fumosorosea EH-506/3 when applied to the skin.

Sporotrichosis is a fungal disease caused by the Sporothrix schenckii complex that includes species such as S. brasiliensis, S. schenckii sensu stricto, S. globosa, S. luriei, S. mexicana, and S. pallida, which exhibit different potentially antigenic molecular components. The immune response of susceptible hosts to control infection and disease caused by these fungi has been little studied. Besides, the fungus-host interaction induces the activation of different types of immune response. This mini-review analyzes and discusses existing reports on the identification and functional characterization of molecules from species of the S. schenckii complex with clinical relevance, and the mechanisms that mediate the type and magnitude of the immune response in experimental models in vivo and in vitro. This knowledge is expected to contribute to the development of protective and therapeutic strategies against sporotrichosis and other mycoses.

Introduction and Objective: Nosocomial invasive fungal infections, particularly aspergillosis, are an increasing problem in immunocompromised patients. The presented study evaluates fungal diversity and the presence of Aspergillus in air samples from two hospitals., Materials and Methods: Over the course of one year (rainy and dry seasons), the air was sampled from three areas in two hospitals (1 and 2) using a single-stage Andersen viable particle sampler (Thermo Scientific, Waltham, MA, USA). The fungi were identified by macro- and micromorphology, and the number of colony forming units (CFU)/m(3) air and their richness, abundance, and diversity were determined. Isolates Aspergillus genus were characterized by their thermotolerance., Results: The CFU/m(3) air was similar at both hospitals during the two seasons, but different between the sampled areas. Results showed 10 fungal genera for hospital 1, and 8 for hospital 2. The most abundant were Penicillium, Cladosporium and Aspergillus. The thermotolerance test confirmed the identification of A. fumigatus section Fumigati. The highest growth rate was found in Aspergillus section Nigri., Conclusion: Determining the fungal diversity in the two hospitals was important because all the species have the potential to be pathogenic, especially the section Fumigati.

Background: Chagas disease is a key health problem in Latin America and is caused and transmitted by Trypanosoma cruzi and triatomine bugs, respectively. Control of triatomines has largely relied on the use pyrethroids, which has proved to be ineffective in the long term. Alternatively, the use of entomopathogenic fungi has been implemented to control triatomine bugs. These fungi are highly efficient as they induce a reduction in immune response on insects. Meccus pallidipennis is the main triatomine vector of Chagas disease in Mexico. In this work we investigated the effects of two entomopathogenic fungi, Metarhizium anisopliae and Isaria fumosorosea, on M. pallidipennis nymphs in terms of insect survival and immune response., Methods: We had an infected and a control group for each fungal species and assessed: a) insect survival during 30 days; and, b) phenoloxidase (PO) and prophenoloxidase (proPO; two key traits in insect immune response) at 24, 48, 96 and 144 h. For survival we used Kaplan-Meier survival analysis while for immune response we used factorial, repeated-measures ANOVA for each fungal species., Results: Animals treated with M. anisopliae died sooner than animals treated with I. fumosorosea. Infected animals showed lower PO and proPO values than sham individuals, with a clear decrease in these parameters at 24 h with no further changes after this time., Conclusions: Our study widens the possibility of entomopathogenic fungi being used for triatomine control. The negative effect on PO and proPO seems mediated by a down-regulation of the triatomine immune response.

Cell wall (CW) components of fungus Sporothrix schenckii are the major inductors antigens of immune responses. The immunodominant 60 kDa glycoprotein (gp60) has been shown to be associated with the virulence of this fungus but its role in experimental sporotrichosis is unknown. In this work, the immunological effects of CW-purified gp60 were investigated in a model of experimental subcutaneous sporotrichosis in normal and gp60-preimmunized C57BL/6 and BALB/c mice strains which were then infected with S. schenckii conidia. Results showed that both mice strains use different cytokine profiles in order to fight S. schenckii infection; C57BL/6 mice seem to use a Th17 response while BALB/c mice tend to depend on a Th1 profile. Preimmunization with gp60 showed a downregulatory effect on the immune response since cytokines levels were diminished in both strains. There were no significant differences in the magnitude of dorsoplantar inflammation between gp60-preimmunized and nonimmunized mice of both strains. However, skin lesions due to the infection in gp60-preimmunized mice were more severe in BALB/c than in C57BL/6 mice, suggesting that the antigen exerts a higher downregulatory effect on the Th1 response.

Human and animal fungal pathogens are a growing threat worldwide leading to emerging infections and creating new risks for established ones. There is a growing need for a rapid and accurate identification of pathogens to enable early diagnosis and targeted antifungal therapy. Morphological and biochemical identification methods are time-consuming and require trained experts. Alternatively, molecular methods, such as DNA barcoding, a powerful and easy tool for rapid monophasic identification, offer a practical approach for species identification and less demanding in terms of taxonomical expertise. However, its wide-spread use is still limited by a lack of quality-controlled reference databases and the evolving recognition and definition of new fungal species/complexes. An international consortium of medical mycology laboratories was formed aiming to establish a quality controlled ITS database under the umbrella of the ISHAM working group on "DNA barcoding of human and animal pathogenic fungi." A new database, containing 2800 ITS sequences representing 421 fungal species, providing the medical community with a freely accessible tool at http://www.isham.org/ and http://its.mycologylab.org/ to rapidly and reliably identify most agents of mycoses, was established. The generated sequences included in the new database were used to evaluate the variation and overall utility of the ITS region for the identification of pathogenic fungi at intra-and interspecies level. The average intraspecies variation ranged from 0 to 2.25%. This highlighted selected pathogenic fungal species, such as the dermatophytes and emerging yeast, for which additional molecular methods/genetic markers are required for their reliable identification from clinical and veterinary specimens., (© The Author 2015. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)