A monophyletic group of black yeast-like fungi containing opportunistic pathogens around Exophiala spinifera is analyzed using sequences of the small-subunit (SSU) and internal transcribed spacer (ITS) domains of ribosomal DNA. The group contains yeast-like and annellidic species (anamorph genus Exophiala) in addition to sympodial taxa (anamorph genera Ramichloridium and Rhinocladiella). The new species Exophiala oligosperma, Ramichloridium basitonum, and Rhinocladiella similis are introduced and compared with their morphologically similar counterparts at larger phylogenetic distances outside the E. spinifera clade. Exophiala jeanselmei is redefined. New combinations are proposed in Exophiala: Exophiala exophialae for Phaeococcomyces exophialae and Exophiala heteromorpha for E. jeanselmei var. heteromorpha.A significant portion of the species of black yeasts and their filamentous relatives, anamorphs of members of the order Chaetothyriales, are regularly encountered as causative agents of human mycoses (9). They exhibit a relatively high degree of molecular diversity (10) but seem to possess common factors which enable them to invade the human host, resulting in a bewildering diversity of mycoses, such as chromoblastomycosis, mycetoma, brain infection, and other types of phaeohyphomycosis (9). In harboring a wide array of clinically relevant species, the Chaetothyriales are unique in the fungal kingdom: they are only matched by the Onygenales, the order containing the dermatophytes and the dimorphic pathogens. Understanding the species diversity of the Chaetothyriales and their specific ecology is of considerable medical relevance.This wide species spectrum is only poorly understood, as until recently insufficient markers were available for a reliable distinction of taxa. Morphology is poorly developed in these fungi, and when present, very similar microscopic structures can be expressed in phylogenetically remote species (15). Sequencing studies of the ribosomal operon have shown that this gene can be successfully applied to species delimitation and identification. A large number of new taxa have to be introduced; many of these have a pathogenic potential.In an extended 18S ribosomal DNA (rDNA) sequencing study of black yeasts and their allies, Haase et al. (15) showed that the phylogenetic tree of the Chaetothyriales is poorly resolved, which indicates a radiation of taxa within a relatively short evolutionary period. All anamorph genera concerned proved to be polyphyletic (15); the morphological entities were nevertheless maintained for practical reasons. The single teleomorph genus in the order, Capronia, was found throughout the tree but appeared to have limited clinical relevance.
Background SARS-CoV-2 predisposes patients to secondary infections; however, a better understanding of the impact of coinfections on the outcome of hospitalized COVID-19 patients is still necessary. Aim To analyse death risk due to coinfections in COVID-19 patients. Methods We evaluated the Odds of death of 212 severely ill COVID-19 patients, with detailed focus on the risks for each pathogen, site of infection, comorbidities and length of hospitalization. Findings The mortality rate was 50.47%. Fungal and/or bacterial isolation occurred in 89 patients, of which 83.14% died. Coinfected patients stayed hospitalized longer and had an increased Odds of dying (OR = 13.45, R 2 =0.31). The risk of death was increased by bacterial (OR=11.28) and fungal (OR=5.97) coinfections, with increased levels of creatinine, leukocytes, urea and C-reactive protein. Coinfections increased the risk of death if patients suffer from cardiovascular disease (OR= 11.53), diabetes (OR=6.00) or obesity (OR=5.60) in comparison with patients with these comorbidities but without pathogen isolation. The increased risk of death was detected for negative-coagulase Staphylococcus (OR=25.39), Candida non- albicans (OR=11.12), S. aureus (OR=10.72), Acinetobacter spp. (OR=6.88), Pseudomonas spp. (OR=4.77) and C. albicans (OR=3.97). The high-risk sites of infection were blood, tracheal aspirate and urine. Patients with coinfection undergoing invasive mechanical ventilation were 3.8 times more likely to die than those without positive cultures. Conclusions Severe COVID-19 patients with secondary coinfections required longer hospitalization and had higher risk of death. The early diagnosis of coinfections is essential to identify high-risk patients and to determine the right interventions to reduce mortality.
Deschampsia antarctica Desv. (Poaceae) represents one of the two vascular plants that have colonized the Antarctic continent, which is usually exposed to extreme environmental conditions. In this work, we have characterized the endophytic fungi associated with the leaves of D. antarctica. Endophytic fungi were recovered from 91 individual plants from diVerent points of Admiralty Bay at King George Island, Antarctica. A total of 26 fungal isolates were obtained from 273 leaf fragments. All isolates were identiWed by analysis of the sequences of the internal transcribed spacer region (ITS) of the rDNA. Alternaria and Phaeosphaeria were the most frequent genera associated with the plant. Other fungal isolates were identi-Wed as Entrophospora sp. and several undescribed Ascomycete species. An interesting result was obtained for the isolates UFMGCB 215 and UFMGCB 262, which were related to fungi associated with bryophytes present in boreal ecosystems. Some isolates showed low identity in the ITS sequences to sequences of fungal species deposited in GenBank, suggesting that these fungi could be new species. This work is the Wrst report on fungal endophytes associated with leaves of the Antarctic grass D. antarctica.
Protozoan parasites belonging to genera Leishmania and Trypanosoma are the etiological agents of severe neglected tropical diseases (NTDs) that cause enormous social and economic impact in many countries of tropical and sub-tropical areas of the world. In our screening program for new drug leads from natural sources, we found that the crude extract of the endophytic fungus Cochliobolus sp. (UFMGCB-555) could kill 90% of the amastigote-like forms of Leishmania amazonensis and inhibit by 100% Ellman's reagent reduction in the trypanothione reductase (TryR) assay, when tested at 20 µg mL−1. UFMGCB-555 was isolated from the plant Piptadenia adiantoides J.F. Macbr (Fabaceae) and identified based on the sequence of the internally transcribed spacer (ITS) regions of its ribosomal DNA. The chromatographic fractionation of the extract was guided by the TryR assay and resulted in the isolation of cochlioquinone A and isocochlioquinone A. Both compounds were active in the assay with L. amazonensis, disclosing EC50 values (effective concentrations required to kill 50% of the parasite) of 1.7 µM (95% confidence interval = 1.6 to 1.9 µM) and 4.1 µM (95% confidence interval = 3.6 to 4.7 µM), respectively. These compounds were not active against three human cancer cell lines (MCF-7, TK-10, and UACC-62), indicating some degree of selectivity towards the parasites. These results suggest that cochlioquinones are attractive lead compounds that deserve further investigation aiming at developing new drugs to treat leishmaniasis. The findings also reinforce the role of endophytic fungi as an important source of compounds with potential to enter the pipeline for drug development against NTDs.
Peripheral blood samples of 138 co-habitants from 25 families with recently diagnosed cases of visceral leishmaniasis in the Metropolitan Region of Belo Horizonte, Minas Gerais, Brazil, were analyzed by indirect fluorescent antibody test (IFAT), rK39 and Leishmania chagasi Enzyme Linked Immunosorbent Assay (ELISA), intradermal skin-test and Polymerase Chain Reaction (PCR) over a 12-month period. The cumulative positivity was significantly higher by PCR (29.7%) than by IFAT, rK39 ELISA, L. chagasi ELISA and intradermal skin-test (5.1%, 6.5%, 14.5% and 2.9%, respectively). In addition, the cytokine profile was measured in 16 of the 138 volunteers, of whom eight were asymptomatic carriers and eight were non-infected co-habitants. The innate immunity cells from asymptomatic carriers displayed, upon in vitro antigenic stimulation, a modulated increase in cytokine synthesis that was distinct from that observed in non-infected volunteers. This study suggests that the identification of a large proportion of asymptomatic carriers is facilitated when more than one diagnostic method is applied and that a mixed pattern of immune response is correlated with clinical status of asymptomatic individuals. These observations suggest also that asymptomatic infection by L. chagasi is a frequent event and that control programs could benefit by including this indicator in their interventions.
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