RESUMEN
New mold species are increasingly reported in invasive fungal infections. However, these fungi are often misdiagnosed or undiagnosed due to the use of inappropriate laboratory diagnostic tools. Tropical countries, such as French Guiana, harbor a vast diversity of environmental fungi representing a potential source of emerging pathogens. To assess the impact of this diversity on the accuracy of mold-infection diagnoses, we identified mold clinical isolates in French Guiana during a five-month follow-up using both microscopy and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. In total, 38.8% of the 98 obtained molds isolates could not be identified and required a DNA-based identification. Fungal diversity was high, including 46 species, 26 genera, and 13 orders. Fungal ecology was unusual, as Aspergillus species accounted for only 27% of all isolates, and the Nigri section was the most abundant out of the six detected Aspergillus sections. Macromycetes (orders Agaricales, Polyporales, and Russulales) and endophytic fungi accounted for respectively 11% and 14% of all isolates. Thus, in tropical areas with high fungal diversity, such as French Guiana, routine mold identification tools are inadequate. Molecular identifications, as well as morphological descriptions, are necessary for the construction of region-specific mass spectrum databases. These advances will improve the diagnosis and clinical management of new fungal infections. LAY SUMMARY: In French Guiana, environmental fungal diversity may be a source of emerging pathogens. We evaluated microscopy and mass spectrometry to identify mold clinical isolates. With 39% of unidentified isolates, a region-specific mass spectrum database would improve the diagnosis of new fungal infections.
RESUMEN
Since 1817, seven cholera pandemics have plagued humankind. As the causative agent, Vibrio cholerae, is autochthonous in the aquatic ecosystem and some studies have revealed links between outbreaks and fluctuations in climatic and aquatic conditions, it has been widely assumed that cholera epidemics are triggered by environmental factors that promote the growth of local bacterial reservoirs. However, mounting epidemiological findings and genome sequence analysis of clinical isolates have indicated that epidemics are largely unassociated with most of the V. cholerae strains in aquatic ecosystems. Instead, only a specific subset of V. cholerae El Tor 'types' appears to be responsible for current epidemics. A recent report examining the evolution of a variety of V. cholerae strains indicates that the current pandemic is monophyletic and originated from a single ancestral clone that has spread globally in successive waves. In this review, we examine the clonal nature of the disease, with the example of the recent history of cholera in the Americas. Epidemiological data and genome sequence-based analysis of V. cholerae isolates demonstrate that the cholera epidemics of the 1990s in South America were triggered by the importation of a pathogenic V. cholerae strain that gradually spread throughout the region until local outbreaks ceased in 2001. Latin America remained almost unaffected by the disease until a new toxigenic V. cholerae clone was imported into Haiti in 2010. Overall, cholera appears to be largely caused by a subset of specific V. cholerae clones rather than by the vast diversity of V. cholerae strains in the environment.
Asunto(s)
Cólera/epidemiología , Cólera/microbiología , ADN Bacteriano/análisis , Epidemias , Vibrio cholerae/genética , Genoma Bacteriano , Haití/epidemiología , Humanos , México/epidemiología , Filogenia , Análisis de Secuencia de ADN , América del Sur/epidemiologíaRESUMEN
Cholera appeared in Haiti in October 2010 for the first time in recorded history. The causative agent was quickly identified by the Haitian National Public Health Laboratory and the United States Centers for Disease Control and Prevention as Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. Since then, >500 000 government-acknowledged cholera cases and >7000 deaths have occurred, the largest cholera epidemic in the world, with the real death toll probably much higher. Questions of origin have been widely debated with some attributing the onset of the epidemic to climatic factors and others to human transmission. None of the evidence on origin supports climatic factors. Instead, recent epidemiological and molecular-genetic evidence point to the United Nations peacekeeping troops from Nepal as the source of cholera to Haiti, following their troop rotation in early October 2010. Such findings have important policy implications for shaping future international relief efforts.
Asunto(s)
Cólera/epidemiología , Epidemias , Vibrio cholerae O1/clasificación , Vibrio cholerae O1/aislamiento & purificación , Cólera/mortalidad , Haití/epidemiología , Humanos , Personal Militar , Epidemiología Molecular , Nepal , Naciones UnidasAsunto(s)
Cólera/epidemiología , Cólera/transmisión , Brotes de Enfermedades , Haití/epidemiología , HumanosRESUMEN
Cystic echinococcosis (CE) is a widespread and severe zoonotic disease caused by infection with the larval stage of the eucestode Echinococcus granulosus sensu lato. The polymorphism exhibited by nuclear and mitochondrial markers conventionally used for the genotyping of different parasite species and strains does not reach the level necessary for the identification of genetic variants linked to restricted geographical areas. EmsB is a tandemly repeated multilocus microsatellite that proved its usefulness for the study of genetic polymorphisms within the species E. multilocularis, the causative agent of alveolar echinococcosis. In the present study, EmsB was used to characterize E. granulosus sensu lato samples collected from different host species (sheep, cattle, dromedaries, dogs, and human patients) originating from six different countries (Algeria, Mauritania, Romania, Serbia, Brazil, and the People's Republic of China). The conventional mitochondrial cox1 and nad1 markers identified genotypes G1, G3, G5, G6, and G7, which are clustered into three groups corresponding to the species E. granulosus sensu stricto, E. ortleppi, and E. canadensis. With the same samples, EmsB provided a higher degree of genetic discrimination and identified variations that correlated with the relatively small-scale geographic origins of the samples. In addition, one of the Brazilian single hydatid cysts presented a hybrid genotypic profile that suggested genetic exchanges between E. granulosus sensu stricto and E. ortleppi. In summary, the EmsB microsatellite exhibits an interesting potential for the elaboration of a detailed map of the distribution of genetic variants and therefore for the determination and tracking of the source of CE.
Asunto(s)
ADN de Helmintos/genética , Equinococosis/parasitología , Equinococosis/veterinaria , Echinococcus granulosus/clasificación , Echinococcus granulosus/genética , Variación Genética , Repeticiones de Microsatélite , Argelia , Animales , Brasil , Camelus , Bovinos , China , Análisis por Conglomerados , Perros , Echinococcus granulosus/aislamiento & purificación , Genotipo , Humanos , Mauritania , Rumanía , Sensibilidad y Especificidad , Serbia , OvinosRESUMEN
With more than 50 countries affected and 200,000 notified cases per year (which is a gross underestimation), cholera, after having almost disappeared 50 years ago, has again become the calamity it was in the 19th century. To understand how this plague could have suddenly reappeared and spread all over the world and then taken root in the world's poorest countries, we give a brief outline here of the epidemiology of cholera, divided into three parts. The first part examines the origin and spread of the cholera pandemics, and particularly that of the seventh pandemic which, more than forty years after it began, is still, raging, in successive epidemic waves. The second part describes the modes of transmission of the cholera vibrio as they are seen in the field, examining the case of the cholera epidemic in the Comoro Islands in 1998. The third part shows the links between cholera and humanitarian disasters, through the use of concrete examples (refugee settlements, cyclones and volcanic eruptions). In conclusion, all the arguments presented here highlight not only the role of water and the lack of hygiene, but also the role of technical progress, especially in international transports, in the spread of the present pandemic.