RESUMO
Bloodstream infections (BSI) caused by Candida species are the fourth cause of healthcare associated infections worldwide. Non-albicans Candida species emerged in the last decades as agents of serious diseases. In this study, clinical and microbiological aspects of six patients with BSI due to the Meyerozyma (Candida) guilliermondii species complex from an oncology reference center in Brazil, were evaluated. To describe demographic and clinical characteristics, medical records of the patients were reviewed. Molecular identification of the isolates was performed by ITS1-5.8S-ITS2 region sequencing. Antifungal susceptibility was evaluated by the EUCAST method and the minimal inhibitory concentrations (MIC) assessed according to the epidemiological cutoff values. Virulence associated phenotypes of the isolates were also studied. Ten isolates from the six patients were evaluated. Five of them were identified as Meyerozyma guilliermondii and the others as Meyerozyma caribbica. One patient was infected with two M. caribbica isolates with different genetic backgrounds. High MICs were observed for fluconazole and echinocandins. Non-wild type isolates to voriconazole appeared in one patient previously treated with this azole. Additionally, two patients survived, despite infected with non-wild type strains for fluconazole and treated with this drug. All isolates produced hemolysin, which was not associated with a poor prognosis, and none produced phospholipases. Aspartic proteases, phytase, and esterase were detected in a few isolates. This study shows the reduced antifungal susceptibility and a variable production of virulence-related enzymes by Meyerozyma spp. In addition, it highlights the poor prognosis of neutropenic patients with BSI caused by this emerging species complex. LAY ABSTRACT: Our manuscript describes demographic, clinical and microbiological characteristics of patients with bloodstream infection by the Meyerozyma guilliermondii species complex at a reference center in oncology in Brazil.
Assuntos
Candidíase/sangue , Saccharomycetales/genética , Saccharomycetales/patogenicidade , Sepse/microbiologia , Adulto , Antifúngicos/farmacologia , Brasil , Candidíase/microbiologia , Estudos de Casos e Controles , Farmacorresistência Fúngica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Serviço Hospitalar de Oncologia/estatística & dados numéricos , Estudos Retrospectivos , Saccharomycetales/efeitos dos fármacos , Saccharomycetales/isolamento & purificação , Adulto JovemRESUMO
In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecular oxygen O2 (1Δg). Using analytical tools, including elemental analysis, ultraviolet/infrared absorption spectrophometry and MALDI-TOF mass spectrometry analysis, we characterized both pigment content in mycelia and secreted to the culture media as 1,8-dihydroxynaphthalene (DHN)-melanin type compound. This is sole melanin-type in M. fijiensis. Isolated melanins irradiated with a Nd:YAG laser at 532 nm produced monomol light emission at 1270 nm, confirming generation of O2 (1Δg), a highly reactive oxygen specie (ROS) that causes cellular death by reacting with all cellular macromolecules. Intermediary polyketides accumulated in culture media by using tricyclazole and pyroquilon (two inhibitors of DHN-melanin synthesis) were identified by ESI-HPLC-MS/MS. Additionally, irradiation at 532 nm of that mixture of compounds and whole melanized mycelium also generated O2 (1Δg). A pigmented-strain generated more O2 (1Δg) than a strain with low melanin content. Banana leaves of cultivar Cavendish, naturally infected with different stages of black Sigatoka disease, were collected from field. Direct staining of the naturally infected leaf tissues showed the presence of melanin that was positively correlated to the disease stage. We also found hydrogen peroxide (H2O2) but we cannot distinguish the source. Our results suggest that O2 (1Δg) photogenerated by DHN-melanin may be involved in the destructive effects of Mycosphaerella fijiensis on banana leaf tissues. Further studies are needed to fully evaluate contributions of melanin-mediated ROS to microbial pathogenesis.
Assuntos
Melaninas/metabolismo , Musa/microbiologia , Micélio/patogenicidade , Naftóis/metabolismo , Folhas de Planta/microbiologia , Saccharomycetales/patogenicidade , Oxigênio Singlete/metabolismo , Fatores de Virulência/metabolismo , Peróxido de Hidrogênio/metabolismo , Luz , Musa/efeitos da radiação , Micélio/metabolismo , Doenças das Plantas/microbiologia , Folhas de Planta/efeitos da radiação , Saccharomycetales/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em TandemRESUMO
Fungi belonging to the genus Scytalidium are widespread around the world. Among them, two species are responsible for human superficial infections mimicking dermatophytosis: Neoscytalidium dimidiatum and Scytalidium hyalinum. Whereas these ascomycetous fungi are endemic in tropical or subtropical countries, both species have a different geographical distribution. Scytalidiosis represents approximately 40% of dermatomycoses in these areas. A few cases of invasive infections due to Scytalidium sp. have also been reported, assessing the ability of these fungi to behave as opportunists. Here we have reviewed the data on N. dimidiatum and S. hyalinum concerning their classification, clinical features, diagnosis and treatment. We also have presented the example of a specific consultation dedicated to nails in Martinique, in order to optimize the diagnosis and treatment of onychomycosis, many of which being due to Scytalidium sp. Even if Scytalidium cases are still rare in temperate countries, imported cases may increase in the future due to immigration and travel.
Assuntos
Micoses/microbiologia , Saccharomycetales , Antifúngicos/uso terapêutico , Terapia Combinada , Dermatomicoses/diagnóstico , Dermatomicoses/epidemiologia , Dermatomicoses/microbiologia , Dermatomicoses/terapia , Farmacorresistência Fúngica Múltipla , Emigração e Imigração , Doenças Endêmicas , Fungemia/diagnóstico , Fungemia/epidemiologia , Fungemia/microbiologia , Humanos , Martinica/epidemiologia , Micoses/diagnóstico , Micoses/epidemiologia , Micoses/terapia , Onicomicose/diagnóstico , Onicomicose/epidemiologia , Onicomicose/microbiologia , Onicomicose/terapia , Infecções Oportunistas/epidemiologia , Infecções Oportunistas/microbiologia , Infecções Oportunistas/terapia , Ambulatório Hospitalar , Equipe de Assistência ao Paciente , Saccharomycetales/classificação , Saccharomycetales/efeitos dos fármacos , Saccharomycetales/isolamento & purificação , Saccharomycetales/patogenicidade , Saccharomycetales/fisiologia , Especificidade da Espécie , Viagem , Clima TropicalRESUMO
The fungi Nomuraea rileyi and Isaria tenuipes (=Paecilomyces tenuipes) are ecologically obligate, widespread pathogens of lepidopterans. Bioassays were carried out to evaluate the activity of oil-suspended conidia of N. rileyi and I. tenuipes against larvae of Spodoptera frugiperda, Spodoptera exigua, Helicoverpa zea, and Heliothis virescens. The tests consisted of two bioassay sets. In the first set, conidia of N. rileyi and I. tenuipes were suspended in water+Tween 80, and in vegetable (canola, soybean) and mineral (proprietary mixture of alkanes and cyclic paraffins) oils, and tested against S. frugiperda. Both fungi were highly compatible with oils and caused mortalities near 100% in all oil treatments; the lowest LT(50) values were 4.7 days for N. rileyi in mineral oil and 6.0 days for I. tenuipes in soybean oil. The second set included additional fungal strains and oil formulations (mineral, canola, sunflower, olive and peanut oils) tested against larvae of S. exigua, S. frugiperda, H. zea and H. virescens. The highest activity was that of N. rileyi in mineral oil against Spodoptera spp., with LT(50) values of 2.5 days (strain ARSEF 135) and 3 days (strain ARSEF 762) respectively. For two different isolates of I. tenuipes the lowest LT(50) values (5.1-5.6 days respectively) were obtained with mineral oil formulations against Spodoptera spp. and H. zea respectively. Additionally, we tested both fungi against prepupae of all four lepidopteran species. Mortalities with I. tenuipes against S. exigua ranged from 90% to 100% (strains ARSEF 2488 and 4096); N. rileyi caused 95% mortality on S. frugiperda. The activity of formulations depended on host species and oil used; Spodoptera spp. was more susceptible to these fungi than Heliothis and Helicoverpa. The results indicate that a comprehensive evaluation of these entomopathogens in agriculture using oil application technologies is advisable, particularly, in organic and sustainable settings.