Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 29
Filter
Add more filters










Publication year range
1.
Bull Soc Pathol Exot ; 103(1): 14-8, 2010 Feb.
Article in French | MEDLINE | ID: mdl-20099054

ABSTRACT

We report the first case of primary amoebic meningoencephalitis in a 9-year-old boy in Guadeloupe. The outcome was rapidly fatal in 7 days. The patient presumably acquired the infection by swimming and diving in a basin supplied by natural thermal water 1 week before onset of the disease. The possibility of a free-living amoeba infection was suspected both on the negativity of all bacterial and viral initial tests and on the observation of peculiar cells in stained cerebrospinal fluid samples. Although the amoeba was not isolated, Naegleria fowleri could be identified by polymerase chain reaction with specific primers on DNA extracted from frozen cerebrospinal fluid samples. Furthermore, as the internal transcribed spacer (ITS1) region of DNA is variable in length between the different strains of N. fowleri, sequencing of the amplified ITS1 demonstrated that the responsible N. fowleri strain belongs to a common genotype present in the American and European continent.


Subject(s)
Central Nervous System Protozoal Infections/parasitology , DNA, Protozoan/cerebrospinal fluid , Meningoencephalitis/parasitology , Naegleria fowleri/genetics , Base Sequence , Central Nervous System Protozoal Infections/cerebrospinal fluid , Child , DNA, Protozoan/chemistry , Fatal Outcome , Genotype , Guadeloupe , Humans , Male , Meningoencephalitis/cerebrospinal fluid , Molecular Sequence Data
2.
Water Res ; 36(14): 3429-38, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12230188

ABSTRACT

This study investigates the effects of pulsed electric fields on the inactivation of trophozoite form of Naegleria lovaniensis Ar9M-1 in batch and flow processes, systematically examining the lethal effect of field strength, pulse duration, number of pulses, and pulse frequency. Our results show that amoebae eradication is modulated by pulse parameters, composition of the pulsing medium, and physiological state of the cells. Cell survival is not related to the energy delivered to the cell suspension during the electrical treatment. For a given energy a strong field applied for a short cumulative pulse duration affects viability more than a weak field with a long cumulative pulsation. We also determine the optimal electrical conditions to obtain an inactivation rate higher than 95% while using the least energy. Flow processes allow to treat large-scale volumes. Our results show that the most efficient flow process for amoeba eradication requires a field parallel to the flow. Pulsed electric fields are a new and attractive method for inactivating amoebae in large volumes of fresh water.


Subject(s)
Naegleria/isolation & purification , Water Microbiology , Water Purification/methods , Animals , Electricity , Survival , Water Supply
3.
Protist ; 152(2): 115-21, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11545434

ABSTRACT

Trophozoites of several isolates from one location in Australia have failed consistently to transform into flagellates, although they display all other characteristics of the genus Naegleria. When changing the standard transformation test, flagellates were produced. In phylogenetic trees derived from partial small subunit ribosomal DNA (SSUrDNA) sequences, one of these strains branches close to a cluster comprising N. clarki, N. australiensis, N. italica and N. jadini. It is proposed that these Australian isolates represent a new species, named N. fultoni (strain NG885). Failing to form flagellates since their isolation, even when different transformation procedures are used, are two Naegleria strains from Chile and Indonesia. In SSUrDNA-based phylogenetic trees the Chilean strain clusters with N. pussardi and the Indonesian strain clusters with N. galeacystis, but the degree of sequence difference from these described species (3.5% and 2.2%, respectively) is sufficient to propose that both of the strains represent new species, named N. chilensis (strain NG946) and N. indonesiensis (strain NG945), respectively. The close relationships between each of the new species and the Naegleria species with which they cluster in SSUrDNA-based trees were confirmed by ribosomal internal transcribed spacer region (ITS) sequence comparisons. In France, several non-flagellating N. fowleri strains were isolated from one location. ITS rDNA sequence comparisons indicated that they correspond to a 'type' of N. fowleri found in both Europe and the USA. A redefinition of the genus Naegleria is proposed as a consequence of these and previous findings.


Subject(s)
Amebiasis/diagnosis , Eukaryota/genetics , Naegleria/genetics , Amebiasis/parasitology , Animals , Base Sequence , DNA, Protozoan/analysis , Eukaryota/physiology , Molecular Sequence Data , Naegleria/classification , Naegleria/physiology , Phylogeny , Sequence Analysis, DNA
4.
Appl Environ Microbiol ; 67(7): 2927-31, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11425704

ABSTRACT

Free-living Naegleria fowleri amoebae cause primary amoebic meningoencephalitis (PAM). Because of the apparent conflict between their ubiquity and the rarity of cases observed, we sought to develop a model characterizing the risk of PAM after swimming as a function of the concentration of N. fowleri. The probability of death from PAM as a function of the number of amoebae inhaled is modeled according to results obtained from animals infected with amoeba strains. The calculation of the probability of inhaling one or more amoebae while swimming is based on a double hypothesis: that the distribution of amoebae in the water follows a Poisson distribution and that the mean quantity of water inhaled while swimming is 10 ml. The risk of PAM for a given concentration of amoebae is then obtained by summing the following products: the probability of inhaling n amoebae x the probability of PAM associated with inhaling these n amoebae. We chose the lognormal model to assess the risk of PAM because it yielded the best analysis of the studentized residuals. Nonetheless, the levels of risk thereby obtained cannot be applied to humans without correction, because they are substantially greater than those indicated by available epidemiologic data. The curve was thus adjusted by a factor calculated with the least-squares method. This provides the PAM risk in humans as a function of the N. fowleri concentration in the river. For example, the risk is 8.5 x 10(-8) at a concentration of 10 N. fowleri amoebae per liter.


Subject(s)
Amebiasis/transmission , Meningoencephalitis/transmission , Models, Biological , Naegleria fowleri , Swimming , Water/parasitology , Amebiasis/mortality , Amebiasis/parasitology , Animals , Humans , Meningoencephalitis/mortality , Meningoencephalitis/parasitology , Mice , Models, Animal , Risk Assessment
5.
Epidemiol Infect ; 126(2): 231-9, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11349974

ABSTRACT

Two cases of legionellosis occurring 3 years apart were acquired in the same French thermal spa and were apparently due to the same strain of Legionella pneumophila serogroup 1, as shown by genomic macrorestriction analysis. Minor differences between the two isolates were found by random amplification PCR profiling which showed an additional band with one of the isolates. Analysis of 107 L. pneumophila strains isolated from the spa waters by genome macrorestriction failed to identify the infective strain, but a closely related L. pneumophila serogroup 3 strain differing from the clinical isolates by only one band was found. To determine if the clinical L. pneumophila serogroup 1 isolates was better adapted for intracellular multiplication than related serogroup 3 environmental isolates, the growth kinetics of six isolates were determined in co-culture with Acanthamoeba lenticulata. One clinical isolate failed to grow within amoeba, while the other clinical isolate yielded the highest increase in bacterial cell count per amoeba (1,200%) and the environmental isolates gave intermediate values. Genetic analysis of L. pneumophila isolates by DNA macrorestriction does not therefore appear to reflect their growth kinetics within amoeba, and is not sufficiently discriminatory to identify potentially virulent strains.


Subject(s)
Legionella pneumophila/genetics , Water Microbiology , Amoeba , Animals , Baths , Electrophoresis, Gel, Pulsed-Field , Humans , Legionella pneumophila/growth & development , Legionella pneumophila/isolation & purification , Legionnaires' Disease/etiology
6.
Parasitol Res ; 86(8): 634-41, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10952262

ABSTRACT

Monoclonal antibody (Mab) 5D12 against Naegleria fowleri was analyzed for species specificity. Mab 5D12 reacted with a ubiquitous epitope present on the membrane of N. fowleri but not with soluble antigens. The Mab did not react with N. lovaniensis, N. gruberi, N. australiensis, or Acanthamoeba castellanii. The decreased reactivity of Mab 5D12 with N. fowleri observed after periodate oxidation, after digestion of carbohydrate moieties by three glycosidases, or after treatment of amebas with tunicamycin strongly suggests that the antigenic determinant has a polysaccharide component. Inhibition of the reactivity of Mab 5D12 by soluble saccharides supports the idea that N-acetyl or amino groups may play an important role in the recognition of the carbohydrate component of the epitope by the Mab. The specificity of Mab 5D12 makes this an ideal reagent for the identification of N. fowleri in environmental samples or in clinical specimens.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Protozoan/immunology , Antibody Specificity , Antigens, Protozoan/immunology , Naegleria fowleri/immunology , Animals , Epitopes , Naegleria/immunology , Polysaccharides/immunology , Species Specificity
7.
J Eukaryot Microbiol ; 47(2): 116-21, 2000.
Article in English | MEDLINE | ID: mdl-10750838

ABSTRACT

Internal transcribed spacers (ITS) and the 5.8S ribosomal gene of 21 Naegleria fowleri strains and eight other species including Naegleria gruberi were sequenced. The results showed that this region can help differentiate between and within species. The phylogeny of Naegleria spp. deduced from the ITS and the 5.8S gene produced four major lineages, fowleri-lovaniensis, galeacystis-italica-clarki-gruberi-australiensis, andersoni-jamiesoni, and pussardi, that fit perfectly with those inferred from the 18S rRNA gene analysis. The N. gruberi isolate, NG260, was closely related to Naegleria pussardi. The other N. gruberi isolates branched together with Naegleria australiensis in another lineage. The ITS and 5.8S results for N. fowleri were congruent with those previously deduced by RAPD analysis. The phylogenetic analysis inferred from ITS and RAPD data revealed two major groups. The French Cattenom and Chooz and South Pacific strains constituted the first group. The second group encompassed the strains corresponding to the Euro-American and Widespread RAPD variants and shared the same substitution in the 5.8S gene. In addition, it was possible to define species specific primers in ITS regions to rapidly identify N. fowleri.


Subject(s)
DNA, Ribosomal/genetics , Naegleria fowleri/genetics , Naegleria/classification , Naegleria/genetics , Phylogeny , RNA, Ribosomal, 5.8S/genetics , Animals , DNA, Protozoan/genetics , Genetic Variation , Naegleria fowleri/classification , RNA, Protozoan/genetics , Random Amplified Polymorphic DNA Technique
8.
Appl Environ Microbiol ; 64(8): 2977-81, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9687460

ABSTRACT

In this study, 30 strains of the pathogenic free-living amoeba Naegleria fowleri were investigated by using the randomly amplified polymorphic DNA (RAPD) method. The present study confirmed our previous finding that RAPD variation is not correlated with geographical origin. In particular, Mexican strains belong to the variant previously detected in Asia, Europe, and the United States. In France, surprisingly, strains from Cattenom gave RAPD patterns identical to those of the Japanese strains. In addition, all of these strains, together with an additional French strain from Chooz, exhibited similarities to South Pacific strains. The results also confirmed the presence of numerous variants in Europe, whereas only two variants were detected in the United States. The two variants found in the United States were different from the South Pacific variants. These findings do not support the previous hypothesis concerning the origin and modes of dispersal of N. fowleri.


Subject(s)
Genetic Variation , Naegleria fowleri/genetics , Animals , Asia , DNA, Protozoan/analysis , Europe , Genes, Protozoan , Naegleria fowleri/classification , Naegleria fowleri/isolation & purification , Random Amplified Polymorphic DNA Technique , United States
9.
Appl Environ Microbiol ; 64(3): 955-9, 1998 Mar.
Article in English | MEDLINE | ID: mdl-9501435

ABSTRACT

Detection of pathogenic Naegleria fowleri in environmental water samples, which is necessary for the prevention of primary amoebic meningoencephalitis, generally requires concentrating the samples. Two concentration techniques, filtration and centrifugation, were used to study the recovery of N. fowleri, in vegetative or cystic form, that had been mixed with the two other thermotolerant Naegleria species, N. lovaniensis and N. australiensis. Counting of amoebae was performed by the most probable number method on 10 water replicates of 100 ml and 10 ml each. With both concentration methods, recovery was better for cysts than for trophozoites (53% +/- 21% versus 5% +/- 5% by filtration and 57% +/- 25% versus 22% +/- 5% by centrifugation). The recovery of Naegleria trophozoites by filtration was very low, and centrifugation was significantly better than filtration in recovery of Naegleria trophozoites (22% +/- 5% versus 5% +/- 5%; P < 0.001). For cysts, however, filtration appeared as efficient as centrifugation, with equivalent values for recovery (53% +/- 21% versus 57% +/- 25%; P > 0.7). Although the recovery of cysts of N. fowleri obtained by filtration (51% +/- 24%) appeared higher than that by centrifugation (36% +/- 23%), the difference was not significant (P > 0.1). Both concentration methods have highly variable recovery rates, making accurate quantification of low concentrations (< 100/liter) of N. fowleri in the environment difficult.


Subject(s)
Fresh Water/parasitology , Naegleria fowleri/isolation & purification , Animals , Centrifugation , Filtration
11.
J Clin Microbiol ; 31(10): 2758-63, 1993 Oct.
Article in English | MEDLINE | ID: mdl-8253977

ABSTRACT

Monoclonal antibodies (MAbs) reactive to the pathogenic amoeba Naegleria fowleri were analyzed by enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay, Western blotting (immunoblotting), and radioimmunoprecipitation assay (RIPA). Two MAbs (3A4 and 5D12) showed reactivity by ELISA with all N. fowleri strains tested and no reactivity with the five other Naegleria species, N. lovaniensis, N. gruberi, N. australiensis, N. jadini, and N. andersoni. These MAbs reacted with the three morphological forms of N. fowleri (trophozoites, cysts, and flagellates). The reactivity on Western blots was suppressed by treatment with metaperiodate, suggesting a carbohydrate epitope. Differences in reactivity patterns between trophozoites and cysts observed with radioimmunoprecipitation assay might reflect differences in biological properties. The formalin stability of the epitope may be useful in detecting N. fowleri in fixed biopsies and in investigating the pathological process.


Subject(s)
Antibodies, Monoclonal/immunology , Naegleria fowleri/classification , Naegleria/classification , Animals , Enzyme-Linked Immunosorbent Assay , Female , Mice , Mice, Inbred BALB C , Naegleria/immunology , Naegleria/pathogenicity , Naegleria fowleri/immunology , Naegleria fowleri/pathogenicity , Radioimmunoprecipitation Assay
12.
Ann Pediatr (Paris) ; 39(5): 326-32, 1992 May.
Article in French | MEDLINE | ID: mdl-1616253

ABSTRACT

A placebo-controlled multicenter study was carried out to evaluate the effectiveness and safety of Actapulgite in infants and children with acute diarrhea. One hundred and thirteen patients, with a mean age of 28 months, were enrolled by pediatricians in the office. As recommended during acute diarrhea, the dosage of Actapulgite was doubled during the first three treatment days (2 to 4 packets a day according to the patient's weight), and reduced by half thereafter. The main effectiveness criteria was passage of the first normally formed stool, which denotes normalization of intestinal transit time. The first normally formed stool was recorded after two days of treatment with Actapulgite and was followed, on the next day, by a second normal stool, denoting complete recovery. The greater effectiveness of Actapulgite as compared with the placebo was demonstrated by the fact that both the first and the second normally formed stools were passed one day earlier with the active treatment (p = 0.01 and p = 0.002, respectively). In addition, resumption of a normal diet occurred significantly earlier with Actapulgite (4.4 days) than with the placebo (5.1 days). In addition to being effective, the study drug proved remarkably well tolerated. This study is especially valuable because of its office setting and the use of exclusively clinical criteria with a strict methodology.


Subject(s)
Diarrhea/drug therapy , Magnesium Compounds , Magnesium/therapeutic use , Silicon Compounds , Silicon/therapeutic use , Acute Disease , Adolescent , Child , Child, Preschool , Diarrhea, Infantile/drug therapy , Double-Blind Method , Female , Humans , Infant , Male , Placebos
13.
Bull Soc Pathol Exot ; 85(3): 226-31, 1992.
Article in French | MEDLINE | ID: mdl-1422274

ABSTRACT

We report here the third case of Acanthamoeba keratitis discovered in France in a 30 year-old man wearing soft contact lenses. Amoebas of Acanthamoeba genus could be isolated twice from his corneal ulcer with simple ocular swabs. Owing to medical treatment alone, a successful healing of his eye was obtained. The isolated strain was studied morphologically and biochemically: the cysts observed microscopically after silver stain possessed less than six arms surrounded by a non reticulated ectocyst and belonged to group II defined by Pussard and Pons. But the isoenzymatic study of the ocular strain by isofocusing did not allow us to identify it with any one of the 18 reference strains used, although these represent 14 different described species.


Subject(s)
Acanthamoeba Keratitis/parasitology , Acanthamoeba/cytology , Acanthamoeba/enzymology , Isoenzymes/analysis , Acanthamoeba/isolation & purification , Adult , Animals , Cornea/parasitology , Humans , Male , Silver Staining
14.
Parasitol Res ; 78(6): 479-81, 1992.
Article in English | MEDLINE | ID: mdl-1359532

ABSTRACT

We report for the first time the isolation in Europe of Naegleria fowleri showing a type of restriction-fragment-length polymorphism (RFLP) usually found in Australia. The presence of this type as well as the European type fluctuated with time in the cooling waters of the nuclear power station investigated. Two possible explanations for the appearance of the Australian N. fowleri type in Europe are presented.


Subject(s)
Naegleria fowleri/isolation & purification , Polymorphism, Restriction Fragment Length , Water , Animals , Australia , Europe , Naegleria fowleri/classification , Naegleria fowleri/genetics
15.
Heredity (Edinb) ; 68(2): 173-181, 1992 Feb.
Article in English | MEDLINE | ID: mdl-29231202

ABSTRACT

The genetic structure of two populations of Naegleria lovaniensis, comprising 71 isolates collected from the same local geographical area was investigated by isoenzyme analysis. Allelic variation at seven polymorphic enzymatic loci allowed identification of 45 distinctive genotype associations. Analysis of single locus variation reveals that most of them are close to Hardy-Weinberg equilibrium, which indicates segregation and free recombination between alleles. The recovery of a relatively high number of distinct genotypic associations (most of them being unique), and the absence of linkage disequilibrium between genotypes at the different loci also support the existence of recombination. Although we have no idea about the process involved, the results clearly indicate that genetic exchanges occur, at least occasionally, in natural populations of N. lovaniensis.

17.
J Protozool ; 36(2): 179-81, 1989.
Article in English | MEDLINE | ID: mdl-2724184

ABSTRACT

The allozyme survey was extended to 7 strains of Naegleria gruberi and N. jadini in order to further characterize the genetic structure of these free-living amoebas. As formerly known for several characters the electrophoretic evidence reveals considerable heterogeneity at the genetic level among N. gruberi strains. Moreover, 2 distinct gene pools, that might likely represent natural taxa, are clearly identified. The single strain of N. jadini appears evolutionarily related to 1 group of N. gruberi which is also related to N. a. australiensis.


Subject(s)
Biological Evolution , Genetic Variation , Naegleria/genetics , Alleles , Animals , Genotype , Naegleria/enzymology
18.
Parasitol Res ; 75(8): 595-8, 1989.
Article in English | MEDLINE | ID: mdl-2771927

ABSTRACT

Isoenzymatic typing of the different species of Naegleria was studied by comparing isoelectric focusing on axenic and nonaxenic strains using the most discriminating enzymes: lactate dehydrogenase (LDH), malic enzyme (ME), beta-hydroxybutyrate dehydrogenase (beta-HBDH), superoxide dismutase (SOD), and acid phosphatase (AP). The results show that bacteria in nonaxenic cultures have no influence on the interpretation of zymograms. The specificity of the enzymatic patterns of each strain is maintained in all of these enzymatic systems except LDH. With SOD, the existence of a supplementary isoenzyme among all of the nonaxenic strains is probably linked to an enzymatic induction phenomenon.


Subject(s)
Isoenzymes/classification , Naegleria/classification , Animals , Evaluation Studies as Topic , Germ-Free Life , Isoelectric Focusing , Methods , Naegleria/enzymology , Species Specificity
19.
Genetics ; 115(2): 265-70, 1987 Feb.
Article in English | MEDLINE | ID: mdl-17246363

ABSTRACT

Electrophoretic variation for 15 enzyme-coding genes was studied in various Naegleria (Rhizopoda, Vahlkampfiidae) species. The occurrence of complex banding patterns provided the first evidence of a diploid structure of the genome of these amoebae. The putative loci identified were found not to be linked and the genotypic distribution suggested chromosomal recombination for one species (Naegleria lovaniensis).

20.
Ann Gastroenterol Hepatol (Paris) ; 21(6): 361-2, 1985 Dec.
Article in French | MEDLINE | ID: mdl-4096498

ABSTRACT

Two different conditions are contrasted: mucosal prolapse in children aged between 2 and 5 years and total prolapse, which is very rare. Mucosal prolapse has become very rare in industrialised countries because of the excellent improvement in nutrition since the war, while this remains a very serious condition in under-developed countries. It is rapidly cured, provided the therapeutic errors are avoided, in particular cerclage. Sclerosis with quinine-urea is indicated in this situation. The various causes are discussed: in particular, the abnormal fixation of the rectum and the absence of the sacral curvature. The predisposing factors are essentially prolonged time spent on the pot, constipation and prolonged diarrhoea and, most importantly, malnutrition and prematurity. Total prolapse in very rare; it is about 15 centimetres long curved posteriorly and often incoercible. It occurs in younger infants and even neonates. It is often irreducible and therefore requires surgery in certain cases. It frequently disappears after the age of 8 years. There are a number of very different causes, not only malnutrition and prematurity and, in this clinical context, strain plays an important role and may be due to a vesical or urethral stone or to a congenital abnormality of these organs, but also abnormalities of the rectal segment with disorders of innervation, connective tissue diseases, any diseases affecting the internal sphincter, in particular congenital abnormalities. Abnormalities of the intrinsic rectal innervation with loss of sensitivity are frequent and can be due to denervations caused by a surgical operation (Hirschsprung's operation, for example). Abnormalities of the baso-receptors have also been observed.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Rectal Prolapse , Child, Preschool , Humans
SELECTION OF CITATIONS
SEARCH DETAIL
...