Genotype-specific features reduce the susceptibility of South American yellow fever virus strains to vaccine-induced antibodies.

The resurgence of yellow fever in South America has prompted vaccination against the etiologic agent, yellow fever virus (YFV). Current vaccines are based on a live-attenuated YF-17D virus derived from a virulent African isolate. The capacity of these vaccines to induce neutralizing antibodies against the vaccine strain is used as a surrogate for protection. However, the sensitivity of genetically distinct South American strains to vaccine-induced antibodies is unknown. We show that antiviral potency of the polyclonal antibody response in vaccinees is attenuated against an emergent Brazilian strain. This reduction was attributable to amino acid changes at two sites in central domain II of the glycoprotein E, including multiple changes at the domain I-domain II hinge, which are unique to and shared among most South American YFV strains. Our findings call for a reevaluation of current approaches to YFV immunological surveillance in South America and suggest approaches for updating vaccines.

[Tinea capitis: clinical features and therapeutic alternatives]. / Tinea capitis: aspectos clínicos y alternativas terapéuticas.

A descriptive observational and cross-sectional study was carried out. The clinical characteristics, etiologic agents, treatments and outcome of 33 cases of tinea capitis in the Mycology Unit at Francisco J. Muñiz Hospital of Buenos Aires City between January 2015 and December 2019 were analyzed. The median age of the patients was 7 years, 21 of whom were male, 3 were HIV-positive and 22 had pets. The isolated etiologic agents were the following: Microsporum canis in 22 cases, Trichophyton tonsurans in 8, Nannizzia gypsea in 2 and Trichophyton mentagrophytes in one patient. Suppurative tinea capitis (krion Celsi) was detected in 10 cases and the same number of patients presented other skin locations of their dermatophytosis in addition to those in the scalp. Twenty-one cases were orally treated with griseofulvin and 12 with terbinafine. Those patients with suppurative tinea capitis received drops of betamethasone by mouth besides the antifungal drugs. All patients had good clinical and mycological response to the treatments, all lesions disappeared, and mycological studies turned negative by the end of the treatments. We conclude that both drugs were effective for the treatment of tinea capitis; however, lesions in those cases receiving terbinafine involuted more slowly.

Antifungal Resistance in Clinical Isolates of Aspergillus spp.: When Local Epidemiology Breaks the Norm.

Aspergillosis is a set of very frequent and widely distributed opportunistic diseases. Azoles are the first choice for most clinical forms. However, the distribution of azole-resistant strains is not well known around the world, especially in developing countries. The aim of our study was to determine the proportion of non-wild type strains among the clinical isolates of Aspergillus spp. To this end, the minimum inhibitory concentration of three azoles and amphotericin B (used occasionally in severe forms) was studied by broth microdilution. Unexpectedly, it was found that 8.1% of the isolates studied have a diminished susceptibility to itraconazole. This value turned out to be similar to the highest azole resistance rate reported in different countries across the world.

The Response of Litter-Associated Myxomycetes to Long-Term Nutrient Addition in a Lowland Tropical Forest.

Myxomycetes (plasmodial slime molds) are abundant protist predators that feed on bacteria and other microorganisms, thereby playing important roles in terrestrial nutrient cycling. Despite their significance, little is known about myxomycete communities and the extent to which they are affected by nutrient availability. We studied the influence of long-term addition of N, P, and K on the myxomycete community in a lowland forest in the Republic of Panama. In a previous study, microbial biomass increased with P but not N or K addition at this site. We hypothesized that myxomycetes would increase in abundance in response to P but that they would not respond to the sole addition of N or K. Moist chamber cultures of leaf litter and small woody debris were used to quantify myxomycete abundance. We generated the largest myxomycete dataset (3,381 records) for any single locality in the tropics comprised by 91 morphospecies. In line with our hypothesis, myxomycete abundance increased in response to P addition but did not respond to N or K. Community composition was unaffected by nutrient treatments. This work represents one of very few large-scale and long-term field studies to include a heterotrophic protist highlighting the feasibility and value in doing so.

[Clinical problems in medical mycology: Problem number 51]. / Problemas clínicos en micología médica: problema número 51.

A 48 year-old immunocompetent woman, who had a nodular lesion in the neck and a dense infiltrate at the lower lobe of the left lung, presented at the Mycology Unit of Muñiz Hospital of Buenos Aires City. The pulmonary infiltrate disappeared spontaneously 3 months later. The histopathological study of the nodular lesion showed capsulated yeasts (mucicarmin and alcian blue positive stains) compatible with Cryptococcus. The mycological study of a new sample, obtained by a nodular puncture, allowed the isolation of yeasts, identified as Cryptococcus gattii (VGII). Latex test for Cryptococcus capsular antigen in serum was positive (1/100). CSF cultures rendered negative results. Fluconazole at a daily dose of 800mg was given during 45 days with partial improvement; as cultures from a new clinical sample were positive for Cryptococcus, the antimycotic was changed to itraconazole 400mg/day for 5 months, with an excellent clinical response.

[Clinical problems in medical mycology: Problem number 52]. / Problemas clínicos en micología médica: problema número 52.

The case of a 60 year old woman with hemoptysis and a thin-walled cavitary lesion at the upper lobe of the right lung is presented. The woman presented at the Mycology Unit of the Muñiz Hospital in Buenos Aires City 3 months after the beginning of her clinical manifestations. A hyaline micelial fungus with chlamido-arthroconidias was isolated from the bronchoalveolar lavage. Immunodiffusion and counter-immnunoelectrophoresis with coccidioidin and histoplasmin rendered positive results against both antigents, and skin tests with coccidioidin and histoplasmin were also positive with strong reactions. The isolated fungus was identified as Coccidioides posadasii at the National Microbiology Institute Carlos Malbrán, by means of a molecular technique. The patient was treated with itraconazole by oral route at a daily dose of 200mg with good clinical response, but due to the persistence of the lung cavity, a surgical removal of the upper lobe of the right lung had to be scheduled.

Cryptococcosis in an Infectious Diseases Hospital of Buenos Aires, Argentina. Revision of 2041 cases: Diagnosis, clinical features and therapeutics.

BACKGROUND: Cryptococcosis is still a life-threatening mycosis that continues to be of serious concern in Latin American countries, especially among HIV+positive population. However, there is not any reliable information about the prevalence of this disease in this region. AIMS: The aim of this study is to report data of 2041 patients with cryptococcosis that were attended at the Infectious Diseases Hospital F. J. Muñiz over a 30 year-period. METHODS: Information about demographic and clinical data, survival time and the applied treatment, was taken from the Mycology Unit database. Mycological exams from different clinical samples were performed. Cryptococcal capsular antigen in serum and cerebrospinal fluid was detected through the latex agglutination technique. Cryptococcus isolates were phenotypically identified and the genotype was determined in some of them. Susceptibility tests were carried out following M27-A3 document. RESULTS: Seventy five percent of HIV+positive patients and 50% of the HIV-negative population were males. Mean ages were 34.1 in HIV+positive patients and 44.8 in the HIV-negative. Cryptococcosis was associated with AIDS in 98% of the cases. Meningeal compromise was seen in 90% of the patients. Although cerebrospinal fluid rendered more positive results, blood culture was the first diagnostic finding in some cases. Cryptococcal antigen showed positive results in 96.2% of the sera samples and in the 93.1% of the cerebrospinal fluid samples. Most of the isolates were Cryptococcus neoformans and belonged to genotype VNI. Minimal inhibitory concentration values were mostly below the epidemiological cutoff values. CONCLUSIONS: We observed that thanks to a high level of clinical suspicion, early diagnosis, combined therapy and intracranial pressure control by daily lumbar punctures, the global mortality rate has markedly decreased through the years in the analyzed period.

[Clinical problems in medical mycology: Problem number 50]. / Problemas clínicos en micología médica: problema número 50.

We present the case of a 34 year-old man, HIV-positive, who had suffered a disseminated histoplasmosis treated with amphotericin B one year before his admission. He was admitted at the Infectious Diseases Muñiz Hospital with a non-lithiasic chlolecystitis. During the clinical examination perigenital skin lesions compatible with tinea cruris, as well as proximal subungual onychomycoses of toenails, were observed. Microsporum gypseum was isolated from both types of lesions. Oral terbinafine led to a good clinical response. Treatment prescription was a big challenge in this patient because he was receiving HAART and itraconazole, and there was scarce experience in the treatment of nail infections due to M. gypseum.

[Clinical problems in medical mycology: Problem number 49]. / Problemas clínicos en micología médica: problema número 49.

The case of a 22 year-old pregnant woman, suffering an infectious disease with skin lesions on the head, is presented. The patient referred a systemic mycosis 5 years before, treated with oral antifungal, with good clinical response. The mycological study of the skin clinical samples showed multiple budding yeast like elements consistent with Paracoccidioides, and the same organism was isolated in cultures. Physical examination and images studies did not show other location of the mycosis. The patient was treated with oral cotrimoxazole during pregnancy and lactation; afterwards this treatment was stopped and replaced by itraconazole by oral route at a daily dose of 200mg due to the poor clinical response observed with the first treatment. A rapid and favorable evolution was seen with the latter.

Perichaena longipes, a new myxomycete from the Neotropics.

A new species of myxomycete, Perichaena longipes, is described from 56 sporocarp specimens that appeared in moist chamber cultures prepared with samples of decaying plant materials collected in Panama, Costa Rica and Brazil. This new species is distinguished from the morphologically similar species P. pedata on the basis of the much longer stipe, lighter peridium and the unique ornamentation of the capillitium. The nuc 18S ribosomal DNA sequences obtained from four specimens of P. longipes support the distinction of this new taxon and its separation from P. pedata. Furthermore, maximum likelihood phylogeny supports earlier evidence that species currently within the genus Perichaena do not form a monophyletic clade. Instead they appear to form three separate branches within the bright-spored clade. The first clade includes P. longipes together with several species of Trichia and Metatrichia, the second includes P. pedata and P. chrysosperma, and the third clade is composed of P. corticalis, P. depressa and P. luteola.

Similarities and differences among the chromosomes of the wild guinea pig Cavia tschudii and the domestic guinea pig Cavia porcellus (Rodentia, Caviidae).

Cavia tschudii Fitzinger, 1867 is a wild guinea pig species living in South America that according to the analysis of mitochondrial genes is the closest wild form of the domestic guinea pig. To investigate the genetic divergence between the wild and domestic species of guinea pigs from a cytogenetic perspective, we characterized and compared the C, G and AgNOR banded karyotypes of molecularly identified Cavia tschudii and Cavia porcellus Linnaeus, 1758 specimens for the first time. Both species showed 64 chromosomes of similar morphology, although C. tschudii had four medium size submetacentric pairs that were not observed in the C. porcellus karyotype. Differences in the C bands size and the mean number of AgNOR bands between the karyotypes of the two species were detected. Most of the two species chromosomes showed total G band correspondence, suggesting that they probably represent large syntenic blocks conserved over time. Partial G band correspondence detected among the four submetacentric chromosomes present only in the C. tschudii karyotype and their subtelocentric homologues in C. porcellus may be explained by the occurrence of four pericentric inversions that probably emerged and were fixed in the C. tschudii populations under domestication. The role of the chromosomal and genomic differences in the divergence of these two Cavia species is discussed.

A small, new gerbil-mouse Eligmodontia (Rodentia: Cricetidae) from dunes at the coasts and deserts of north-central Chile: molecular, chromosomic, and morphological analyses.

A small, new species of gerbil rodents of the genus Eligmodontia from the southwestern dunes of the Atacama Desert in northern Chile is described; the genus had not been reported for this western lowland region. Our description is based on cytogenetic and molecular data, as well as cranial and external morphology. In order to support this hypothesis, we studied 27 specimens captured in Playa Los Choros (Coquimbo) and Copiapó (Atacama), comparing them with samples of all the extant species of the genus. Nineteen individuals consistently showed 2N=50, FN=48, with telocentric chromosomes and G-bands identical to those of the geographically northeastern E. hirtipes; these two groups were geographically separated by E. puerulus (2N = 34, FN = 48). The phylogenetic analysis of 56 Eligmodontia cytochrome-b gene sequences yielded a maximum-likelihood phylogenetic tree where the new species formed a divergent and well-supported clade within the genus, which was also confirmed by unweighted parsimony, minimum evolution, and Bayesian analyses. The new species has K2P genetic distances of 12.8% from the geographically distant E. hirtipes, and 10.3% from E. puerulus. Axes 1 and 2 of Principal Component Analysis based on 12 body and skull measurements clearly separated the new species, the latter having a smaller head+body length (70.6 +/- 3.4 mm, n = 17) and lower weight (11.9 +/- 1.9 g, n = 20). We provide strong evidence to recognize a distinct new western lineage within Eligmodontia genus, Eligmodontia dunaris sp. nov., for which we give a complete taxonomic description and a hypothetical biogeographic scenario. The new species should be considered endangered, due to its level of endemism, its low population numbers (which can be occasionally increased after a blooming desert) and its fragile dry habitat patchily distributed near the Atacama Desert.

Malformaciones Congénitas: Aspectos Generales y Genéticos / Congenital Malformations: General and Genetic Aspects

Los defectos del desarrollo se pueden deber a malformaciones congénitas, deformaciones o disrupciones. El 10% de las malformaciones se atribuyen a causas ambientales el 25% a factores genéticos y el 65% a factores desconocidos probablemente de orden multifactorial. Existe un período de mayor susceptibilidad frente a los teratógenos que corresponde a la etapa donde se están formando la mayoría de los órganos y sistemas. La ingestión de plantas teratogénicas puede dar lugar a anomalías congénitas en los fetos de animales. Los pesticidas como DDT, la contaminación de las aguas por mercurio y los disruptores endocrinos afectan la embriogénesis de las distintas especies del reino animal. También se consideran como factores causantes de malformaciones a los agentes ambientales infecciosos y a algunos medicamentos. Los agentes físicos como los aumentos de temperatura, las condiciones de hipoxia y las radiaciones afectan a distintos organismos, desde los peces al ser humano. La genética de las malformaciones ha sido difícil de establecer, principalmente porque la mayor parte de ellas se caracteriza por presentar manifestaciones fenotípicas diversas, que en muchos casos aparentemente no están relacionadas y que son variables para los individuos afectados. Por otra parte, los estudios realizados indican que frecuentemente, en la determinación genética de las malformaciones participan varios genes y las interacciones de éstos con el ambiente, aunque determinaciones monogénicas se han podido establecer para unos pocos casos. Ilustramos aquí estos dos tipos contrastantes de determinación genética, a través de la descripción de los factores genéticos que estarían involucrados en los defectos del tubo neural y en el síndrome de CHARGE, respectivamente.

Developmental defects may be due to congenital malformations, deformations or disruptions; 10% of malformations are caused by environmental factors, 25% by genetics factors and 65% are due to unknown multifactorial problems. There is a developmental period of greater susceptibility to teratogens, which corresponds to the stages when most organs and systems are being formed. Ingestions of teratogenics plants may result in congenital anomalies in animal foetuses. Pesticide such as DDT, water contamination with the Hg and the endocrine disrupters affect embryogenesis of different animal species. As factors that provoke malformations there are environmental agents, infections and some drugs. Physical agents such as increased temperature, hypoxic conditions and radiation, affect different organisms from fishes to human. Genetic of malformations have been difficult to establish, mainly because most of them are characterized by diverse phenotypic aspects, apparently not related and variable for the different affected organisms. On the other hand, studies realized indicate that frequently in the genetic determination of malformations several genes and their interactions with the environment are involved, although it has been possible to establish monogenic determination for a few cases. Here we contrast these two types of genetic determination, describing the genetic factors involved in the neural tube defects and the CHARGE syndrome, respectively.

[Onychomycosis: multicentre epidemiological, clinical and mycological study]. / Onicomicosis: estudio multicéntrico clínico, epidemiológico y micológico.

BACKGROUND: Onychomycosis accounts for up to 50% of all nail disorders. They can be caused by: yeasts, dermatophytes and non-dermatophyte moulds. OBJECTIVES AND METHODS: A multicentre study designed to determine the prevalence, mycological test results, aetiological agents, and clinical presentation of onychomycosis was carried out. All fingernail and toenail samples taken during a one year period at 9 diagnostic centres were included. RESULTS: A total of 5,961 samples were analysed, of which 82.3% were from toenails and 17.7% from fingernails. The mean age of the patients was 49.7 years, and 66% were females. Direct microscopic examination was positive in 61% of the samples. In adults, 61.2% of toenails were positive using potassium hydroxide (KOH), and 43.7% were positive in cultures. The prevailing aetiological agents belong to the dermatophyte group (82.8%), and distal subungual was the most common clinical form. In fingernails, direct examination showed 59.8% positive samples, and cultures were positive in 52.9%. The prevailing agents were yeasts belonging to Candida species, and onycholysis was the most common lesion. CONCLUSIONS: Direct mycological examinations were positive in 61%, a higher value than that found in other series. Dermatophytes were prevalent in toenails of both sexes, and in finger nails yeast were prevalent in females, and dermatophytes in males. Non-dermatophyte moulds corresponded to 4.8% of toenail and 2.05% of fingernails isolates.

Comparison of the immunogenicity of vaccines prepared from viable Mycobacterium bovis BCG, heat-killed Mycobacterium leprae, and a mixture of the two for normal and M. leprae-tolerant mice

Intradermal vaccines consisting of viable Mycobacterium bovis BCG, heat-killed Mycobacterium leprae, or mixtures of the two were titrated in mice in doses of 10(5.2), 10(5.8), 10(6.4), 10(7.0), and 10(7.6) acid-fast bacilli. The immune response was measured by sensitization (48 to 72 h foot pad enlargement on challenge with 10(7.0) heat-killed M. leprae) and by protection against infection with a viable M. leprae challenge. There was increasing response with increasing dose of vaccine, and overall the responses to the three vaccines were similar. At the lowest dose, however, the combination of BCG and M. leprae gave superior protection. The local reaction to the vaccines in the lower dose range was less severe with the M. leprae vaccine. In another experiment, the three vaccines were compared in normal mice and in mice that had been rendered tolerant by intravenous injection of M. leprae. The tolerant mice developed no measurable sensitization on vaccination with M. leprae, but they developed partial but distinct sensitization on vaccination with BCG, alone or in combination with M. leprae. The tolerant mice developed little or no protection with any of the vaccines, however..

Searches among mycobacterial cultures for antileprosy vaccines

All mycobacteria species share some antigens, so there may be cultivable mycobacterial cultures that can provide vaccine protection against leprosy. Vaccine protection against Mycobacterium leprae infections in mice has been demonstrated for M. leprae itself, as living or heat-killed suspensions, and for Mycobacterium bovis (BCG), as living suspensions. Results are reported here with 17 other cultures. The mycobacterial suspensions were injected intradermally, and the mice were challenged in the footpad with infectious suspensions of M. leprae. In two experiments the mice were also challenged by footpad injections of 10(7) heat-killed M. leprae so the footpad enlargment could be measured. That some mycobacterial suspensions were immunogenic for some of their own antigens was suggested by reactions at the vaccine site and enlargement of the regional lymph nodes. Some mycobacterial suspensions also stimulated footpad enlargement on challenge by homologous suspensions or by challenge with M. leprae suspensions. Consistent protection against infectious challenge with M. leprae was observed only with BCG and M. leprae, however...