RESUMO
INTRODUCTION: Nocardia brasiliensis is a very rarely reported cause of chronic phagedenic ulcerations. We report the case of an elderly woman who developed such an infection after falling on her right leg on the road in the Bresse country (an essentially agricultural and bovine-cattle breading region) and developed a chronic phagedenic ulcer secondarily complicated by nodular lymphangitis of the thigh. CASE REPORT: A 75 year-old woman fell on her right leg on the side of the main road outside her hamlet in the Bresse country and secondarily developed a chronique phagedenic ulceration. We first considered her as suffering from pyoderma gangrenosum. A complete scanning only revealed an autoimmune thyroiditis and a rapidly healing gastric ulceration, and none of the treatments, either local or systemic, helped the skin condition to heal. After 3 weeks of application of a local corticoid ointment, the patient developed fever, general malaise, an exacerbation of her wound and an infiltration of the skin round her knee, together with nodular lymphangitic dissemination. A supplementary bacterial swab disclosed massive proliferation of a slow-growing Gram-positive bacillus, which proved to be Nocardia brasiliensis, together with a methicillino-sensitive Staphylococcus aureus. The treatment with sulfamethoxazole-trimetoprim gave a rash after 12 hours and was changed to amoxicillin and clavulanic acid, which rapidly proved to be permanently effective. DISCUSSION: The revelation of this particular slow-growing bacteria is difficult and requires bacterial swabs. Nocardia brasiliensis is relatively rare in primary skin ulcerations and we discuss the reasons why an elderly women should find this bacteria on the road outside her hamlet in the French countryside. This particular infectious condition requires general scanning, to make sure that the primary skin condition does not extend to other organs. We review the therapeutical options for patients who exhibit allergic reactions to the classically effective antibiotic drugs.
Assuntos
Úlcera da Perna/etiologia , Úlcera da Perna/microbiologia , Nocardiose/complicações , Acidentes por Quedas , Idoso , Combinação Amoxicilina e Clavulanato de Potássio/uso terapêutico , Doença Crônica , Quimioterapia Combinada/uso terapêutico , Feminino , Humanos , Linfangite/etiologia , Nocardia/patogenicidade , Nocardiose/tratamento farmacológicoRESUMO
We investigated the genotypic composition of the digenetic parasite Schistosoma mansoni for its adult stages within the definitive host (the wild rat, Rattus rattus) and for the larval stages within the intermediate host (the snail, Biomphalaria glabrata) both collected at the same transmission site. Our analyses are based upon the recognition and distribution of 200 different multilocus genotypes generated by RAPD markers. While intramolluscan larval infrapopulations are characterized by a low infection rate (0.6 % on average) and low intra-host genetic diversity (1.1 genotype on average per infected snail), adult infrapopulations within rats showed a high infection rate (94%) and a substantial intra-host genetic diversity (34 genotypes on average) linked to high intensities (160 worms per host on average). A single definitive host bearing 105 different genotypes harboured 52 % of the total genetic diversity detected within the whole parasite population. Analysis of the genetic data allowed the identification of various ecological, behavioural and immunological factors which are likely to enhance transmission of multiple parasite genotypes towards the vertebrate hosts. From the distribution of repeated identical multilocus genotypes within the parasite population and among the hosts, we have inferred different parameters of the cercarial transmission efficiency as well as patterns and processes by which vertebrate hosts acquire infection in the field.
Assuntos
Biomphalaria/parasitologia , Variação Genética , Muridae/parasitologia , Doenças dos Roedores/transmissão , Schistosoma mansoni/genética , Esquistossomose mansoni/transmissão , Animais , DNA de Helmintos/análise , Feminino , Genótipo , Guadalupe , Interações Hospedeiro-Parasita , Larva/classificação , Larva/genética , Estágios do Ciclo de Vida , Masculino , Técnica de Amplificação ao Acaso de DNA Polimórfico , Ratos , Doenças dos Roedores/parasitologia , Schistosoma mansoni/classificação , Esquistossomose mansoni/parasitologiaRESUMO
We studied the population genetic structure of 360 and 1247 adult Schistosoma mansoni using seven microsatellite and seven random amplified polymorphic DNA (RAPD) markers, respectively. Parasites were collected from their natural definitive host Rattus rattus in Guadeloupe (West Indies). We found a sex-specific genetic structure, a pattern never before reported in a parasitic organism. Male genotypes were more randomly distributed among rats than female genotypes. This interpretation was consistent with a lower differentiation between hosts for males relative to females, the higher genetic similarity between females in the same host and the observed local (i.e. within-individual-host) differences in allele frequencies between the two sexes. We discuss our results using ecological and immunological perspectives on host-parasite relationships. These results change our view on the epidemiology of schistosomiasis, a serious disease affecting humans in African and American intertropical zones.
Assuntos
DNA de Protozoário/genética , Schistosoma mansoni/genética , Esquistossomose mansoni/epidemiologia , Animais , Sequência de Bases , DNA de Protozoário/química , Evolução Molecular , Feminino , Variação Genética , Genética Populacional , Guadalupe , Interações Hospedeiro-Parasita/genética , Masculino , Repetições de Microssatélites/genética , Dados de Sequência Molecular , Técnica de Amplificação ao Acaso de DNA Polimórfico , Ratos , Schistosoma mansoni/crescimento & desenvolvimentoRESUMO
The distribution of genetic diversity in a local population of the trematode Schistosoma mansoni was determined within and between individual wild rats at a microspatial geographic scale of a standing water transmission site. Using RAPD markers, molecular variance and canonical correspondence analysis were performed to test the significance of genetic differentiation between infrapopulations. Of total gene diversity, 8 and 11% was partitioned between hosts trapped at few metres distance from each other. Significant temporal differentiation (2%) was also detected among schistosomes sampled at 6 month intervals with more infrapopulation pairs differentiated during the dry season of parasite transmission than during the rainy season (45 and 12%, respectively). A combination of factors such as restricted displacement of rats, patchy spatial aggregation of infected snails and limited cercarial dispersion in standing water are likely to promote the genetic differentiation observed between infrapopulations at this microgeographic scale.
Assuntos
DNA de Helmintos/genética , Schistosoma mansoni/genética , Esquistossomose mansoni/epidemiologia , Animais , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , Feminino , Variação Genética , Guadalupe/epidemiologia , Desequilíbrio de Ligação/genética , Masculino , Ratos , Schistosoma mansoni/química , Estações do AnoRESUMO
Random amplified polymorphic DNA (RAPD) markers were used to quantify genetic diversity within and between 5 populations of Schistosoma mansoni within its definitive host (Rattus rattus) and the 5 corresponding populations of the snail intermediate host (Biomphalaria glabrata) from a limited endemic area of murine schistosomiasis on the island of Guadeloupe. Analysis of molecular variance (AMOVA) and canonical correspondence analysis (CCA) were used to test the significance of genetic differentiation between populations. Both methods gave similar results. Of total gene diversity, 15.1% (AMOVA) and 18.8% (CCA) was partitioned between localities for S. mansoni with an absence of association between genetic and geographical distances. Geographical localities accounted for 20.5% (CCA) of the total diversity for B. glabrata populations. The genetic distances between pairs of parasite populations were not correlated with the genetic distances between the corresponding pairs of snail host populations. Such strong patterns of local differentiation of both parasite and snail populations are consistent with predictions based on metapopulation dynamics and may have implications on host-parasite susceptibility relationship through local adaptation processes.
Assuntos
Biomphalaria/genética , Variação Genética , Schistosoma mansoni/genética , Animais , Biomphalaria/parasitologia , Geografia , Guadalupe , Interações Hospedeiro-Parasita , Prevalência , Técnica de Amplificação ao Acaso de DNA Polimórfico , Ratos , Schistosoma mansoni/fisiologia , ÁrvoresAssuntos
Repetições de Microssatélites/genética , Schistosoma mansoni/genética , Alelos , Animais , Primers do DNA , DNA de Helmintos/análise , DNA de Helmintos/genética , Frequência do Gene , Biblioteca Genômica , Guadalupe , Heterozigoto , Dados de Sequência Molecular , Muridae/parasitologia , Reação em Cadeia da Polimerase , Polimorfismo Genético , Sequências Repetitivas de Ácido NucleicoRESUMO
Random-amplified polymorphic DNA markers have been used to assess the amount and the distribution of the genetic diversity of Schistosoma mansoni within a natural population of Biomphalaria glabrata at a transmission site of the murine schistosomiasis focus of Guadeloupe. Despite high infection rate and heavy schistosome load within the definitive hosts (Ratus rattus), prevalences within intermediate snails ranged from 0.2 to 4.8%. Whatever the transmission season may be (rainy vs. dry), most of the infected snails were spatially aggregated and 88.4% of them harbored a single parasite genotype indicative of a monomiracidial infection; 4.7% had dual sex infections and a parasite intensity not exceeding 3 miracidia per snail. A substantial resistance level toward the parasite and recruitment regulatory process within snails may explain in part the observed low parasite prevalences and intensities. Considering such a distribution pattern of larval S. mansoni genetic diversity among B. glabrata, mobility of the definitive hosts, or rapid turnover of infected snails, or both, are required to maintain genetic heterogeneity within adult schistosome populations.