Search results for "amoeba"
showing 10 items of 40 documents
Early Diagnosis of Acanthamoeba Infection during Routine Cytological Examination of Cerebrospinal Fluid
2006
ABSTRACT Early identification of Acanthamoeba in cerebrospinal fluid is mandatory to prevent fatal granulomatous amebic encephalitis. In the case presented here amebic trophozoites were detected in a routine cerebrospinal fluid sample. The antibiotic treatment and the apparently low virulence of this isolate were responsible for the benign progression of the infection.
Amebas intestinales no patógenas: una visión clinicoanalítica
2011
Human beings can be parasitized by various species of intestinal amoebae. Entamoeba histolytica is the only intestinal amoeba recognized to be pathogenic, while other amoeba species, E. dispar, E. moshkovskii, E. hartmanni, E. coli, E. polecki, Endolimax nana and Iodamoeba buetschlii are considered to be non-pathogenic. The aim of this review is to synthesize the main morphological characteristics of the trophozoite and cyst stages of each amoeba as the basis for precise microscopical diagnosis. The difficulty of morphological differentiation among species included in the so-called "Entamoeba complex" entails the use of immunological and molecular diagnoses. In addition, a summary of basic …
Interplay between Intestinal Bacterial Communities and Unicellular Parasites in a Morbidly Obese Population: A Neglected Trinomial
2022
Obesity is an epidemic causing a metabolic health crisis. Herein, the interactions between the gut prokaryotic and eukaryotic communities, metabolic comorbidities and diet were studied. Stool samples from 56 subjects, 47 with type III obesity and 9 with type II obesity and cardiovascular risk or metabolic disease, were assessed for the richness, diversity and ecology of the bacterial gut community through metagenomics, together with the study of the presence of common unicellular eukaryote parasites (Blastocystis sp., Dientamoeba fragilis and Giardia intestinalis) by qPCR. Clinical information regarding metabolic comorbidities and non-alcoholic hepatic fatty liver disease was gathered. To a…
Unexpected postmortem diagnosis of Acanthamoeba meningoencephalitis following allogeneic peripheral blood stem cell transplantation.
2008
Meningoencephalitis caused by pathogenic free-living amebas is usually fatal. Only a few cases of Acanthamoeba meningoencephalitis, diagnosed at autopsy, have been reported following hematopoietic stem cell transplantation. We here report a case of Acanthamoeba meningoencephalitis following allogeneic peripheral blood stem cell transplantation with rapidly evolving neurologic symptoms that remained unexplained. Magnetic resonance imaging failed to show brain lesions and cerebrospinal fluid was negative for microbiological cultures. Definite diagnosis was an unexpected autopsy finding. As overall and teaching hospital autopsy rates are declining worldwide, we must emphasize the need of autop…
Do Intestinal Unicellular Parasites Have a Role in the Inflammatory and Redox Status among the Severely Obese?
2022
The diagnosis of obesity comprises subjects with totally different phenotypes and metabolic profiles. Systemic inflammation and oxidative stress derived from the white adipose tissue are suggested as the link between this disease and the development of insulin resistance and metabolic comorbidities. The presence of unicellular eukaryotic parasites colonizing the human gut ecosystem is a common circumstance, and yet their influence on the inflammatory and redox status of the obese host has not been assessed. Herein, a set of inflammatory and redox biomarkers were assessed together with a parasitological analysis of 97 severely obese subjects. Information was also collected on insulin resista…
Association of colony morphotypes with virulence, growth and resistance against protozoan predation in the fish pathogen Flavobacterium columnare.
2014
Many opportunistic pathogens can alternate between inside- and outside-host environments during their life cycle. The opportunistic fish pathogen Flavobacterium columnare is an inhabitant of the natural microbial community and causes significant yearly losses in aquaculture worldwide. The bacterium grows in varying colony morphotypes that are associated with either virulence (rhizoid type) or resistance to starvation and phages (rough type). Rough type strains can arise spontaneously or can be induced by phage infection. To identify the determinants of morphotype fitness, we measured virulence, growth parameters, biofilm-forming ability and resistance to amoeba and ciliate predation of both…
Transcriptional Upregulation of Genes Related to Virulence Activation in Entamoeba histolytica
2007
Background To understand the molecular basis of virulence variability in Entamoeba histolytica , this study presents results about differential gene expression induced by E. histolytica trophozoites in liver of hamsters in order to produce experimental amebic liver abscess (ALA) and consequently reactivate its virulence. Methods Amebic cultures were studied before (BALA) and after (AALA) inoculation in hamster peritoneal cavity. Markers of pathogenicity such as the rate of erythrophagocytosis, hemolytic activity, and cytotoxic effects on MDCK cell monolayers were evaluated in order to correlate these phenotypic characteristics to differential gene expression between virulent and non-virulen…
Origin and diversity of testate amoebae shell composition: Example of Bullinularia indica living in Sphagnum capillifolium
2017
Testate amoebae are free-living shelled protists that build a wide range of shells with various sizes, shapes, and compositions. Recent studies showed that xenosomic testate amoebae shells could be indicators of atmospheric particulate matter (PM) deposition. However, no study has yet been conducted to assess the intra-specific mineral, organic, and biologic grain diversity of a single xenosomic species in a natural undisturbed environment. This study aims at providing new information about grain selection to develop the potential use of xenosomic testate amoebae shells as bioindicators of the multiple-origin mineral/organic diversity of their proximal environment. To fulfil these objective…
Free-living amoebae in sediments from the Lascaux Cave in France
2013
The Lascaux Cave in France is an old karstic channel where the running waters are collected in a pool and pumped to the exterior. It is well-known that water bodies in the vicinity of humans are suspected to be reservoirs of amoebae and associated bacteria. In fact, the free-living amoebae Acanthamoeba astronyxis, Acanthamoeba castellanii, Acanthamoeba sp. and Hartmannella vermiformis were identified in the sediments of the cave using phylogenetic analyses and morphological traits. Lascaux Cave sediments and rock walls are wet due to a relative humidity near saturation and water condensation, and this environment and the presence of abundant bacterial communities constitute an ideal habitat…
Parasitación intestinal por unicelulares eucariotas en una población con obesidad mórbida: implicaciones clínico-metabólicas
2022
La obesidad es una enfermedad grave y multidimensional que, en la actualidad, ha alcanzado dimensiones pandémicas. Muchos son los mecanismos fisiopatológicos propuestos para intentar explicar el marcado aumento de su incidencia, y que se han orientado a hallar nuevas dianas terapéuticas con las que combatirla. Clásicamente se han señalado los factores ambientales propios del estilo de vida occidental (como la alimentación hipercalórica y el sedentarismo) como relevantes en el desarrollo de esta enfermedad; sin embargo, nuevas evidencias apuntan hacia que también podrían jugar un papel importante elementos infecciosos del medio, con repercusiones tanto perjudiciales como protectoras sobre el…