The intestinal microbiota of a Risso’s dolphin (Grampus griseus): possible relationships with starvation raised by macro-plastic ingestion / La microbiota intestinal del delfín gris (Grampus griseus): posibles relaciones con la inanición provocada por la ingestión de macroplásticos

Ingesting marine plastics is increasingly common in cetaceans, but little is known about their potential effects. Here, by utilizing 16S rRNA gene sequencing, we profiled the intestinal bacterial communities of a stranded Risso’s dolphin (Grampus griseus) which died because of the ingestion of rubber gloves. In this study, we explored the potential relationships between starvation raised by plastic ingestion with the dolphin gut microbiota. Our results showed significant differences in bacterial diversity and composition among the different anatomical areas along the intestinal tract, which may be related to the intestinal emptying process under starvation. In addition, the intestinal bacterial composition of the Risso’s dolphin showed both similarity and divergence to that of other toothed whales, suggesting potential roles of both host phylogeny and habitat shaping of the cetacean intestinal microbiome. Perhaps, the microbiota is reflecting a potentially disordered intestinal microbial profile caused by the ingestion of macro-plastics which led to starvation. Moreover, two operational taxonomic units (0.17% of the total reads) affiliated with Actinobacillus and Acinetobacter lwoffii were detected along the intestinal tract. These bacterial species may cause infections in immunocompromised dolphins which are malnourished. This preliminary study profiles the intestinal microbiota of a Risso’s dolphin, and provides an additional understanding of the potential relationships between starvation raised by ingesting macro-plastics with cetacean gut microbiota.(AU)

Characterization and phylogenetic analysis of a Cunninghamella bertholletiae isolate from a bottlenose dolphin (Tursiops truncatus) / Tipificación y análisis filogenético de una cepa de Cunninghamella bertholletiae aislada de un delfín mular (Tursiops truncatus)

Background. Cunninghamella is a genus of the order Mucorales which includes saprophytic species, rarely causing mycoses. The most frequently reported in human mycoses is the thermophilic species Cunninghamella bertholletiae. However, this species does not appear to cause mucormycosis in animals, so there is scarce information about C. bertholletiae isolates from animals. Aims. In this paper we describe the phenotypic and genotypic characterization, and the phylogenetic analysis, of an isolate of C. bertholletiae involved in a central nervous system mucormycosis in a dolphin. Methods. The isolate studied in this publication was characterized using the current morphological and physiological identification system for Cunninghamella species. DNA sequencing and analysis of the D1/D2 regions of the 26S rRNA gene and the ITS-5.8S rRNA gene sequences were also performed. Results. Colonies were fast-growing, white at first, although they became tannish-gray, covering the whole plate after 7 days of incubation at 30 and 40°C. Limited growth was observed after 7 days at 45°C. The micromorphology showed characteristic erect sporangiophores. The identification of the isolate was confirmed by DNA sequencing of the D1/D2 regions of the 26S and the ITS-5.8S (ITS) rRNA gene sequencing. Conclusions. In the phylogenetic study, the isolate clustered in the same clade as C. bertholletiae neotype strain although some differences were observed in the ITS sequences. In the cetacean cases, the possible sources of infection are unclear. The reasons why this pathogen has been found only in cetaceans and not in other domestic or wild animals are at the moment unknown and need further study (AU)

Antecedentes. Cunninghamella es un género perteneciente al orden Mucorales, que incluye especies saprófitas que raramente causan micosis. De este género, Cunninghamella bertholletiae es la especie termófila más frecuentemente citada en micosis humanas. No obstante, no parece que sea una causa habitual de mucormicosis en animales, ya que es escasa la información sobre cepas de esta especie procedentes de estos. Objetivos. En esta publicación describimos la tipificación fenotípica, genotípica y el análisis filogenético de una cepa de C. bertholletiae causante de una mucormicosis del sistema nervioso central en un delfín. Métodos. La cepa fue tipificada mediante los criterios morfológicos y fisiológicos actualmente utilizados para la identificación de estas especies. También se llevó a cabo la secuenciación y el análisis de los fragmentos génicos D1/D2 26S e ITS-5.8S del ARN ribosómico. Resultados. Las colonias presentaron un crecimiento rápido; eran blanquecinas al principio y se volvieron de color marrón agrisado con el tiempo, y cubrieron totalmente las placas a los 7 días de incubación a las temperaturas de 30 y 40°C. A 45°C, después de 7 días de incubación, el crecimiento fue limitado. Al microscopio se pudieron observar los característicos esporangióforos de esta especie. La identificación de la cepa se confirmó mediante la secuenciación de los fragmentos génicos D1/D2 26S e ITS-5.8S del ARN ribosómico. Conclusiones. En el estudio filogenético, la cepa se agrupó en el mismo clado que la cepa neotipo de C. bertholletiae, aunque se detectaron algunas diferencias en las secuencias correspondientes a los ITS. En los casos causados por esta especie en cetáceos, se desconocen las posibles fuentes de infección. Tampoco se conoce por el momento por qué este patógeno ha sido aislado solo de cetáceos y no de otros animales domésticos o salvajes (AU)