Species distribution and antifungal susceptibility profiles of clinical and environmental Fusarium isolates from Mexico: A multicenter study.

Fusarium spp. has emerged as an opportunistic etiological agent with clinical manifestations varying from localized infections to deep-seated systemic disease. It is also a phytopathogen of economic impact. There are few reports on the species diversity of this genus, and no comprehensive studies on the epidemiology nor the antifungal susceptibility of Fusarium in Mexico. The present multicentric study aims to shed light on the species distribution and antifungal susceptibility patterns of 116 strains of Fusarium isolated from clinical and environmental samples. Isolates were identified by standard phenotypic characteristics and by sequencing of the ITS (internal transcribed spacer), TEF1 (translation elongation factor 1-α), RPB2 (RNA polymerase II core subunit), and/or CAM1 (calmodulin) regions. Susceptibility tests were carried out against 15 antifungals of clinical and agricultural use. Regarding Fusarium distribution, we identified 27 species belonging to eight different species complexes. The most frequently isolated species for both clinical and environmental samples were F. falciforme (34%), F. oxysporum sensu stricto (12%), F. keratoplasticum (8%), and F. solani sensu stricto (8%). All Fusarium isolates showed minimum inhibitory concentrations (MICs) equal to or above the maximum concentration evaluated for fluconazole, 5-fluocytosine, caspofungin, micafungin, and anidulafungin. All isolates had a MIC of ≤16 µg/mL for voriconazole, with a mode of 4 µg/mL. F. verticillioides appeared to be the most susceptible to all antifungals tested.

Cryptococcal Meningitis in a Mexican Neurological Center.

BACKGROUND: Cryptococcal meningitis, one of the most severe infections affecting the central nervous system, often involves severe neurological sequels and high mortality. METHODS: A retrospective review was performed, including 76 cases admitted in a 10-year period at a neurological referral center in Mexico City. From 68 isolates, 52 fungal specimens were identified as part of the Cryptococcus neoformans var. neoformans complex, 15 as C. neoformans var gattii complex, and one as Cryptococcus non- neoformans/gattii . RESULTS: Higher cryptococcal meningitis incidence and severity were found in HIV-infected men; other risk factors frequently observed were diabetes mellitus and labor exposure to poultry. The main clinical manifestations were subacute headache, cognitive alterations, and photophobia (exclusively in HIV patients). MRI was highly sensitive for pathologic findings such as meningeal enhancements and cryptococcomas, most of them associated to C. neoformans complex. Eleven patients developed severe brain vasculitis, as observed by transcranial Doppler. Hydrocephalus with intracranial hypertension was the most frequent complication. CONCLUSIONS: One-half of the population died, and the rest had neurological sequels, mainly neuropsychiatric manifestations and secondary headaches. These patients developed severe functional limitations in performing daily activities in an independent manner.

Advocating for Coccidioidomycosis to Be a Reportable Disease Nationwide in the United States and Encouraging Disease Surveillance across North and South America.

Coccidioidomycosis (Valley fever) has been a known health threat in the United States (US) since the 1930s, though not all states are currently required to report disease cases. Texas, one of the non-reporting states, is an example of where both historical and contemporary scientific evidence define the region as endemic, but we don't know disease incidence in the state. Mandating coccidioidomycosis as a reportable disease across more US states would increase disease awareness, improve clinical outcomes, and help antifungal drug and vaccine development. It would also increase our understanding of where the disease is endemic and the relationships between environmental conditions and disease cases. This is true for other nations in North and South America that are also likely endemic for coccidioidomycosis, especially Mexico. This commentary advocates for US state and territory epidemiologists to define coccidioidomycosis as a reportable disease and encourages disease surveillance in other endemic regions across North and South America in order to protect human health and reduce disease burden.

Species distribution and antifungal susceptibility patterns of Aspergillus isolates from clinical specimens and soil samples in Mexico.

This study aimed to assess the species distribution and antifungal susceptibility patterns of 200 strains of Aspergillus isolated from clinical specimens (n = 146) and soil samples (n = 54) in Mexico. ITS, ß-tubulin, and calmodulin DNA sequencing was performed for species identification. Broth microdilution susceptibility testing for amphotericin B, voriconazole, posaconazole, itraconazole, isavuconazole, anidulafungin, caspofungin, and micafungin was done according to CLSI for all strains. A. fumigatus was most frequently recovered from clinical specimens, while A. niger was commonly encountered in soil, both followed by A. flavus in the second place. A total of 60 (30%) cryptic species were identified, with A. tubingensis and A. tamarii being the most commonly found. The decreased susceptibility to amphotericin B and azoles was 32% for both, and were mainly led by A. fumigatus, whereas this percentage decreased to 9% for caspofungin, particularly in A. terreus. More than 75% of cryptic species were susceptible in vitro to all antifungals. Multi-azole decreased susceptibility was detected only in seven isolates. Given that antifungal resistance in Aspergillus spp. is an increasing worldwide threat that causes major challenges in the clinical management of aspergillosis, these data highlight the need for continuous epidemiological surveillance of these pathogens for the implementation of locally adequate treatment strategies. LAY SUMMARY: This is an epidemiological study in Mexico. A. fumigatus was most frequent in clinical specimens and A. niger in soil samples. A. tubingensis and A. tamarii were the most common cryptic species. Resistance to amphotericin B and azoles was 32% each, and 9% for caspofungin.

Differential Thermotolerance Adaptation between Species of Coccidioides.

Coccidioidomycosis, or Valley fever, is caused by two species of dimorphic fungi. Based on molecular phylogenetic evidence, the genus Coccidioides contains two reciprocally monophyletic species: C. immitis and C. posadasii. However, phenotypic variation between species has not been deeply investigated. We therefore explored differences in growth rate under various conditions. A collection of 39 C. posadasii and 46 C. immitis isolates, representing the full geographical range of the two species, was screened for mycelial growth rate at 37 °C and 28 °C on solid media. The radial growth rate was measured for 16 days on yeast extract agar. A linear mixed effect model was used to compare the growth rate of C. posadasii and C. immitis at 37 °C and 28 °C, respectively. C. posadasii grew significantly faster at 37 °C, when compared to C. immitis; whereas both species had similar growth rates at 28 °C. These results indicate thermotolerance differs between these two species. As the ecological niche has not been well-described for Coccidioides spp., and disease variability between species has not been shown, the evolutionary pressure underlying the adaptation is unclear. However, this research reveals the first significant phenotypic difference between the two species that directly applies to ecological research.

Antifungal Resistance in Candida auris: Molecular Determinants.

Since Candida auris integrates strains resistant to multiple antifungals, research has been conducted focused on knowing which molecular mechanisms are involved. This review aims to summarize the results obtained in some of these studies. A search was carried out by consulting websites and online databases. The analysis indicates that most C. auris strains show higher resistance to fluconazole, followed by amphotericin B, and less resistance to 5-fluorocytosine and caspofungin. In C. auris, antifungal resistance to amphotericin B has been linked to an overexpression of several mutated ERG genes that lead to reduced ergosterol levels; fluconazole resistance is mostly explained by mutations identified in the ERG11 gene, as well as a higher number of copies of this gene and the overexpression of efflux pumps. For 5-fluorocytosine, it is hypothesized that the resistance is due to mutations in the FCY2, FCY1, and FUR1 genes. Resistance to caspofungin has been associated with a mutation in the FKS1 gene. Finally, resistance to each antifungal is closely related to the type of clade to which the strain belongs.

Coccidioidal meningitis in non-AIDS patients. A case series at a Mexican neurological referral center.

BACKGROUND: Coccidioidal meningitis is a life-threatening condition and a diagnostic challenge in cases of chronic meningitis. It is associated to severe complications, like basal arachnoiditis, hydrocephalus, and secondary vasculitis. OBJECTIVE: To present a 20-year retrospective clinical series of coccidioidal meningitis cases at a Mexican neurological referral center. RESULTS: The clinical records of 11 patients, predominantly males, were retrieved. Weight loss and night sweats were observed in 64 % of cases. Neurological signs included intracranial hypertension in 91 % of cases, altered alertness and meningeal syndrome in 72 %, and neuropsychiatric symptoms in 64 %. Mean CSF glucose levels were 30 ± 25 mg/dL, and pleocytosis ranged from 0 to 2218 cells/mm3. The diagnosis was confirmed by coccidioidal antigen latex agglutination in 91 % of cases. Radiological findings were hepatomegaly in 55 % of cases and pneumonia in 45 %. Neuroimaging findings included leptomeningitis in 73 % of cases, pachymeningitis in 45 %, and vascular involvement in 91 %. Less common findings included spinal cord lesion and mycotic aneurism, found in 18 % of cases. A molecular coccidioidal DNA test confirmed the predominance of Coccidioides immitis, detected in 64 % of cases. With respect to the clinical outcome, 46 % of patients died. The survivors suffered from sequels like chronic headache, cognitive alterations, and depression. CONCLUSIONS: Coccidioidal meningitis is an entity with high mortality rates. More than one half of patients suffered disseminated disease. Although meningeal signs are not frequent in chronic meningitis, more than two-thirds of our patients showed mild nuchal rigidity. In addition, cerebral and cerebellar volume loss, associated with cognitive impairment and depression, was often observed in surviving patients during the clinical-radiological follow-up.

Surveillance of antimicrobial resistance in Serratia marcescens in Mexico.

Antimicrobial resistance is a global public health threat. Therefore, surveillance studies are important tools to help direct antimicrobial use. The aim of this study was to investigate antimicrobial resistance in Serratia marcescens isolates collected in 2016-2017 at eight medical centers from two regions of Mexico. Selected S. marcescens isolates were further tested by polymerase chain reaction to detect the presence of genes encoding the ß-lactamases, SHV, TEM or CTX. Antimicrobial resistance continues to be high in Mexico, particularly to ciprofloxacin and aminoglycosides. Also, a widespread prevalence of blaTEM was detected in S. marcescens isolates.

Candidosis vaginal: Revisión de la literatura y situación de México y otros países latinoamericanos / Vaginal Candidiasis: current situation of Mexico and other Latin American countries

Las levaduras del género Candida causan enfermedades en los humanos que abarcan desde infecciones superficiales no graves, hasta sistémicas y potencialmente mortales. La candidiasis o candidosis, es el origen común de enfermedad vaginal y aunque es una infección no considerada como incapacitante, suele causar síntomas molestos que alteran la conducta del paciente. En México se considera la única micosis de reporte obligatorio ante las autoridades sanitarias. Por lo anterior, en este trabajo se efectuó una revisión bibliográfica para conocer el estado del arte de la vulvovaginitis causada por Candida spp. (VVC), y ofrecer una breve descripción acerca de la frecuencia presentada por esta infección en diversos países de Latinoamérica, con especial énfasis en México. Se muestra que las frecuencias de VVC en Latinoamérica, son muy parecidas a las reportadas en países como Estados Unidos de América; asimismo, Candida albicans sigue prevaleciendo como el principal agente etiológico. Las diferencias encontradas entre países desarrollados con respecto a los latinoamericanos, consisten básicamente en los métodos diagnósticos y el tipo de tratamiento. Desafortunadamente, en México, a pesar de que la VVC ocupa el noveno lugar entre las 20 principales causas de enfermedad del país, en muy pocos casos se efectúa la identificación de la especie causante, lo que constituye un dato de importancia epidemiológica, considerado como la base para investigar los factores que aumentan el riesgo de contagio, en especial por especies Candida no-albicans y para determinar si la enfermedad es prevenible o controlable

Yeasts of the genus Candida cause diseases in humans ranging from superficial, non-serious, to systemic and potentially life-threatening infections. Candidiasis or thrush, is the common origin of vaginal disease and although it is not considered disabling, infection usually cause troublesome symptoms that alter the behavior of the patient. In Mexico it is considered the unique mycosis of mandatory reporting to health authorities. Therefore, in this work a literature review was conducted to know the state of the art of the vulvovaginitis caused by Candida spp. (VVC), as well as provide a brief description about the frequency presented by this infection in different countries of Latin America, with special emphasis on Mexico. It shows that the frequencies of VVC in Latin America, are very similar to those reported in countries such as the United States of America; in addition, Candida albicans still prevails as the main etiologic agent. The differences found between developed countries with respect to Latin American countries basically consist of the diagnostic methods and the type of treatment. Unfortunately, in Mexico, while the VVC ranks ninth among the 20 principal causes of disease in the country, in very few cases is carried out the identification of the causative species, which constitutes a fact of epidemiological importance, considered as the basis for investigating the factors that increase the risk of infection, especially by Candida nonalbicans species and to determine if the disease is preventable or controllable

MLST and Whole-Genome-Based Population Analysis of Cryptococcus gattii VGIII Links Clinical, Veterinary and Environmental Strains, and Reveals Divergent Serotype Specific Sub-populations and Distant Ancestors.

The emerging pathogen Cryptococcus gattii causes life-threatening disease in immunocompetent and immunocompromised hosts. Of the four major molecular types (VGI-VGIV), the molecular type VGIII has recently emerged as cause of disease in otherwise healthy individuals, prompting a need to investigate its population genetic structure to understand if there are potential genotype-dependent characteristics in its epidemiology, environmental niche(s), host range and clinical features of disease. Multilocus sequence typing (MLST) of 122 clinical, environmental and veterinary C. gattii VGIII isolates from Australia, Colombia, Guatemala, Mexico, New Zealand, Paraguay, USA and Venezuela, and whole genome sequencing (WGS) of 60 isolates representing all established MLST types identified four divergent sub-populations. The majority of the isolates belong to two main clades, corresponding either to serotype B or C, indicating an ongoing species evolution. Both major clades included clinical, environmental and veterinary isolates. The C. gattii VGIII population was genetically highly diverse, with minor differences between countries, isolation source, serotype and mating type. Little to no recombination was found between the two major groups, serotype B and C, at the whole and mitochondrial genome level. C. gattii VGIII is widespread in the Americas, with sporadic cases occurring elsewhere, WGS revealed Mexico and USA as a likely origin of the serotype B VGIII population and Colombia as a possible origin of the serotype C VGIII population. Serotype B isolates are more virulent than serotype C isolates in a murine model of infection, causing predominantly pulmonary cryptococcosis. No specific link between genotype and virulence was observed. Antifungal susceptibility testing against six antifungal drugs revealed that serotype B isolates are more susceptible to azoles than serotype C isolates, highlighting the importance of strain typing to guide effective treatment to improve the disease outcome.

International Society of Human and Animal Mycology (ISHAM)-ITS reference DNA barcoding database--the quality controlled standard tool for routine identification of human and animal pathogenic fungi.

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.

Candidosis vaginal. primera parte: revisión de la clínica, epidemiología y situación de México / Vaginal candidiasis. first part: epidemiology and current state of Mexico

En esta sección se presentan los datos de diversos autores en cuanto a etiología, epidemiología, fisiopatogenia y el perfil clínico de la candidosis o candidiasis vulvo vaginal, con especial atención al escenario actual en México, país en donde es la única micosis de reporte obligatorio ante las autoridades sanitarias, situación que nos motivó a efectuar la presente revisión bibliográfica. La literatura evaluada contempló el período 2007-2013. La vulvovaginitis por Candida spp (VVC), es una infección que habitualmente no se considera incapacitante, aunque sus manifestaciones clínicas pueden dar lugar a gran estrés en las pacientes. En México, los estudios epidemiológicos, han estado enfocados, principalmente, a describir la frecuencia con la que Candida se asocia a casos de vulvo vaginitis y la respuesta clínica a diferentes terapias; sin embargo, es evidente la falta de estudios que relacionen la presencia de Candida con diversos factores de riesgo, la frecuencia de mujeres que recurren a la automedicación y estudios enfocados a la fisiopatología de la vulvo vaginitis causada por este patógeno. Según la literatura consultada, todas estas circunstancias son conocidas y siguen siendo motivo de estudio en países desarrollados.

This section presents data from different authors in terms of etiology, epidemiology, physiopathogeny and the clinical profile of vulvovaginal candidiasis or vulvovaginal candidosis, with special attention to the current scenario in Mexico, a country where it is the only mycosis of mandatory reporting to health authorities, situation that motivated us to carry out the present literature review. The assessed literature took into account the 2007- 2013 period. The vulvovaginitis by Candida spp. (VVC), is an infection that usually is not considered disabling, but its clinical manifestations can give rise to great stress in patients. In Mexico, the epidemiological studies have been focused, primarily, in describing the frequency with which Candida is associated with cases of vulvovaginitis and the clinical response to different therapies; However, it is evident the lack of studies that relate the presence of Candida with different risk factors, the frequency of women who resort to selfmedication and studies focused on the pathophysiology of the vulvovaginitis caused by this pathogen. According to the literature consulted, these circumstances are known and are still cause for study in developed countries.

Combining forces--the use of Landsat TM satellite imagery, soil parameter information, and multiplex PCR to detect Coccidioides immitis growth sites in Kern County, California.

Coccidioidomycosis is a fungal disease acquired through the inhalation of spores of Coccidioides spp., which afflicts primarily humans and other mammals. It is endemic to areas in the southwestern United States, including the San Joaquin Valley portion of Kern County, California, our region of interest (ROI). Recently, incidence of coccidioidomycosis, also known as valley fever, has increased significantly, and several factors including climate change have been suggested as possible drivers for this observation. Up to date details about the ecological niche of C. immitis have escaped full characterization. In our project, we chose a three-step approach to investigate this niche: 1) We examined Landsat-5-Thematic-Mapper multispectral images of our ROI by using training pixels at a 750 m × 750 m section of Sharktooth Hill, a site confirmed to be a C. immitis growth site, to implement a Maximum Likelihood Classification scheme to map out the locations that could be suitable to support the growth of the pathogen; 2) We used the websoilsurvey database of the US Department of Agriculture to obtain soil parameter data; and 3) We investigated soil samples from 23 sites around Bakersfield, California using a multiplex Polymerase Chain Reaction (PCR) based method to detect the pathogen. Our results indicated that a combination of satellite imagery, soil type information, and multiplex PCR are powerful tools to predict and identify growth sites of C. immitis. This approach can be used as a basis for systematic sampling and investigation of soils to detect Coccidioides spp.

Genetic analysis of the endemic fungal pathogens Coccidioides posadasii and Coccidioides immitis in Mexico.

Coccidioidomycosis (CM) is a mycotic disease that affects mammals, including humans. Official data relative to CM in Mexico has not been collected since 1995, thus its prevalence remains unknown. The objectives of this study were to identify the predominant Coccidioides species in Mexico, infer their current geographical distribution and explore the correlation between species and clinical presentation. We collected 154 strains, which were cultured, inactivated, and processed for DNA extraction. Nine microsatellite loci, the Ag2/PRA gene and Umeyama Region were amplified from each isolate. To infer the current geographical distribution of Coccidioides spp. and to establish a correlation between genotype and clinical presentation, we evaluated genetic population structure under the following grouping criteria: putative origin and clinical presentation records. Microsatellite analysis showed that 82% of the isolates corresponded to C. posadasii and 18% were C. immitis. The species identification results obtained using Umeyama region, Ag2/PRA, and microsatellites of five of the isolates were inconsistent with the data collected for the remaining isolates. C. posadasii strains were found primarily in the northeastern region and C. immitis in the northwestern region. However, there was no relationship between clinical presentation and Coccidioides species. The molecular markers used in this study proved to have a high power of resolution to identify the Coccidioides species recovered in culture. While we found C. posadasii to be the most abundant species in Mexico, more detailed clinical records are needed in order to obtain more accurate information about the infections in specific geographical locations.

AFLP analysis reveals high genetic diversity but low population structure in Coccidioides posadasii isolates from Mexico and Argentina.

BACKGROUND: Coccidioides immitis and C. posadasii cause coccidioidomycosis, a disease that is endemic to North and South America, but for Central America, the incidence of coccidioidomycosis has not been clearly established. Several studies suggest genetic variability in these fungi; however, little definitive information has been discovered about the variability of Coccidioides fungi in Mexico (MX) and Argentina (AR). Thus, the goals for this work were to study 32 Coccidioides spp. isolates from MX and AR, identify the species of these Coccidioides spp. isolates, analyse their phenotypic variability, examine their genetic variability and investigate the Coccidioides reproductive system and its level of genetic differentiation. METHODS: Coccidioides spp. isolates from MX and AR were taxonomically identified by phylogenetic inference analysis using partial sequences of the Ag2/PRA gene and their phenotypic characteristics analysed. The genetic variability, reproductive system and level of differentiation were estimated using AFLP markers. The level of genetic variability was assessed measuring the percentage of polymorphic loci, number of effective allele, expected heterocygosity and Index of Association (IA). The degree of genetic differentiation was determined by AMOVA. Genetic similarities among isolates were estimated using Jaccard index. The UPGMA was used to contsruct the corresponding dendrogram. Finally, a network of haplotypes was built to evaluate the genealogical relationships among AFLP haplotypes. RESULTS: All isolates of Coccidioides spp. from MX and AR were identified as C. posadasii. No phenotypic variability was observed among the C. posadasii isolates from MX and AR. Analyses of genetic diversity and population structure were conducted using AFLP markers. Different estimators of genetic variability indicated that the C. posadasii isolates from MX and AR had high genetic variability. Furthermore, AMOVA, dendrogram and haplotype network showed a small genetic differentiation among the C. posadasii populations analysed from MX and AR. Additionally, the IA calculated for the isolates suggested that the species has a recombinant reproductive system. CONCLUSIONS: No phenotypic variability was observed among the C. posadasii isolates from MX and AR. The high genetic variability observed in the isolates from MX and AR and the small genetic differentiation observed among the C. posadasii isolates analysed, suggest that this species could be distributed as a single genetic population in Latin America.

Clinical comparison of two Mexican coccidioidins.

Coccidioidin, an extract from the saprophytic mycelial form of Coccidioides spp., has been a very useful antigen preparation both for skin and serological tests for coccidioidomycosis. Unfortunately, coccidioidin is not currently available for skin testing in the United States. Coccidioidin has been produced commercially in Mexico by a vaccine and reagents laboratory of the Mexican Federal Government. It also has been produced at the Microbiology Laboratory of the Faculty of Medicine, Universidad Nacional Autónoma de México exclusively as an antigen for research projects. The objective of the study was to compare both coccidioidins in their reactivity and safety when applied in humans. One hundred and eighty-four volunteers were tested; median age was 33 (range 14-82). When the cutoff point is set in 5 mm, 88 subjects (47.8%) had a positive test for the commercial coccidioidin and 76 (41.3%; CI(95%) 0.50, 1.15; P = 0.20) were positive with the research antigen. Seventy-five subjects were positive for both antigens and 96 were negative for both. Fifty-nine subjects (31.3%) reported an adverse reaction after the application of the antigen; they were mostly very mild local reactions. Mexican research coccidioidin is a safe and reliable antigen that can be used for the detection of coccidioidomycosis infection in mammals.

[Genetic characterization of the fungus involved in the first case of coccidioidomycosis described by Alejandro Posadas in 1892]. / Identidad genética del hongo causante del primer caso de coccidioidomicosis descripto por Alejandro Posadas en 1892.

In 1892 Alejandro Posadas described the first worldwide case of coccidioidomycosis in a patient named Domingo Escurra. A preserved necropsy piece from the patient's remains is conserved in the Museum of Pathology of the Medical School, Buenos Aires University. Paraffin-embedded specimens obtained from this piece served to identify the fungus involved in the case. Histological slices from different lesion sites were submitted to a genus-specific immunohistochemical staining in order to select the more suited areas in terms of abundance/integrity of fungal esporangia and endospora. Fungal DNA was amplified from selected deparaffinated slices using a nested PCR designed to amplify a segment of the gen Ag2/PRA and differentiate C. immitis from C. posadasii. This PCR was also applied to two reference strains (C. immitis M38-05, C. posadasii 1-NL) and isolates obtained from four recent coccidioidomycosis cases occurred in Argentina. Amplified products were submitted to sequencing of both DNA strands. The obtained sequences were edited, aligned and compared with C. posadasii (Access N degrees AY536446, strain Silveira) and C. immitis (Access N degrees AY536445) deposited in GenBank. DNA sequences from Escurra's lesions were 100% homologous to the recent Argentinean cases and the reference strain 1-NL. A single point C(R)G difference in position 1228 was observed with respect to sequence of strain C. posadasii Silveira. For the first time, Coccidioides DNA is recovered from a museum piece which is more than 100-year-old. Our results confirm that the original case of Posadas's disease was caused by the recently described C. posadasii.

Identidad genética del hongo causante del primer caso de coccidioidomicosis descripto por Alejandro Posadas en 1892 / Genetic characterization of the fungus involved in the first case of coccidioidomycosis described by Alejandro Posadas in 1892

En 1892, Alejandro Posadas documentó el primer caso mundial de coccidioidomicosis en un paciente argentino de nombre Domingo Escurra. Con el objetivo de identificar la especie de Coccidioides involucrado en ese caso, analizamos una pieza de necropsia del paciente, conservada en el Museo de Patología de la Facultad de Medicina de la Universidad de Buenos Aires, Argentina. La porción del tejido con mayor número de endosporas del hongo libres e integras fue elegida utilizando una coloración inmunohistoquímica específica. El ADN fúngico fue amplificado usando una PCR anidada que reconoce un fragmento del gen Ag2/PRA cuyo polimorfismo diferencia Coccidioides immitis y C. posadasii. Se amplificó además, el ADN de dos cepas de referencia: C. immitis (M38-05) y C. posadasii (1-NL) y de cuatro aislamientos de Coccidioides de pacientes argentinos. Los fragmentos amplificados fueron secuenciados en ambas hebras. Las secuencias fueron editadas, alineadas y comparadas con las depositadas en GenBank C. posadasii (Acceso N° AY536446, cepa Silveira) y C. immitis (Acceso N° AY536445). Las secuencias del Coccidioides del caso Escurra, de los aislamientos argentinos y de la cepa 1-NL fueron idénticos entre sí y mostraron una mutación puntual de C→G en la posición 1228 en comparación con la secuencia de C. posadasii, cepa Silveira. Este es el primer trabajo donde se busca ADN de Coccidioides en una pieza anatómica de museo con más de 100 años de antigüedad. Los resultados confirman que el primer caso de coccidioidomicosis o enfermedad de Posadas documentado mundialmente fue producido por el recientemente descripto C. posadasii.

In 1892 Alejandro Posadas described the first worldwide case of coccidioidomycosis in a patient named Domingo Escurra. A preserved necropsy piece from the patient's remains is conserved in the Museum of Pathology of the Medical School, Buenos Aires University. Paraffin-embedded specimens obtained from this piece served to identify the fungus involved in the case. Histological slices from different lesion sites were submitted to a genus-specific immunohistochemical staining in order to select the more suited areas in terms of abundance/integrity of fungal esporangia and endospora. Fungal DNA was amplified from selected deparaffinated slices using a nested PCR designed to amplify a segment of the gen Ag2/PRA and differentiate C. immitis from C. posadasii. This PCR was also applied to two reference strains (C. immitis M38-05, C. posadasii 1-NL) and isolates obtained from four recent coccidioidomycosis cases occurred in Argentina. Amplified products were submitted to sequencing of both DNA strands. The obtained sequences were edited, aligned and compared with C. posadasii (Access N° AY536446, strain Silveira) and C. immitis (Access N° AY536445) deposited in GenBank. DNA sequences from Escurra's lesions were 100% homologous to the recent Argentinean cases and the reference strain 1-NL. A single point C→G difference in position 1228 was observed with respect to sequence of strain C. posadasii Silveira. For the first time, Coccidioides DNA is recovered from a museum piece which is more than 100-year-old. Our results confirm that the original case of Posadas's disease was caused by the recently described C. posadasii.

Molecular identification of coccidioides isolates from Mexican patients.

Molecular studies of the genome of the fungus Coccidioides have demonstrated two nearly identical, but well-identified species, Coccidioides immitis and C. posadasii, known as "California" and "non-California" species, respectively. The objective of this study was to determine, through molecular methods, whether both species of Coccidioides are present in Mexican patients with coccidioidomycosis and to estimate, their geographical distribution in Mexico. We analyzed 56 clinical isolates of Coccidioides spp. from Mexican patients. Molecular identification of each strain was done by means of real time PCR using TaqMan(R) probes to amplify single nucleotide polymorphisms (SNPs) in four target sequences, loci, named proline 157, proline 174, hexokinase 149 and glucose-synthase 192. SNP analysis identified two of the 56 isolates as Coccidioides immitis and the remaining 54 as C. posadasii. The dual probe assay that included proline 157, proline 174 and glucose-synthase 192 gave consistent results on SNP differentiation between the two species. In contrast, the template matching hexokinase 149 gave negative results for any species in 34 samples. Our results did not show geographical overlap of the species, and they also confirmed that C. posadasii is the most frequent species in Mexico. A vast majority of C. posadasii strains were localized in the north-central region of the country.

Observaciones de micosis pulmonares oportunistas / Opportunistic pulmonary mycosis

Para conocer la frecuencia y tipo de micosis oportunistas en 240 pacientes internados en un hospital de neumología, se practicaron historia clínica y estudios micológicos consistentes en el aislamiento de hongos a partir de muestras de esputo. En cada paciente se tomaron tres muestras seriadas, las cuales fueron procesadas por examen directo, frotis y cultivo de Sabouraud. Con la metodología empleada, los resultados mostraron que de los 240 pacientes en 191 se aislaron una o más especies de hongos oportunistas (79,5%). Sin embargo, de acuerdo a la valoración clínica y a los parámetros de laboratorio, se pudo hacer el diagnóstico de candidosis pulmonar en 57 pacientes (23,7% del total), siendo la micosis oportunista la de mayor frecuencia. Otras micosis observadas fueron: aspergilosis (once), geotricosis (ocho), y nocardiosis (cinco). Asimismo se comenta la utilidad y el valor diagnóstico que tienen los estudios micológicos en el análisis clínico de pacientes con micosis oportunista