First insights into the microbiota within the oral cavity of the pygmy sperm whale (Kogia breviceps)

The number of environmental surveillance reports of the ocean ecosystem through systematic studies on marine mammal health and disease is increasing. Understanding host-microbe interactions in cetaceans may contribute to the identification of compromised populations, microbial markers of disease, and ultimately to scientifically base population management decisions. This study is the first assessment of the oral microbiome of three pygmy sperm whales (Kogia breviceps), found stranded in Atlantic Iberian waters, by 16S rDNA-amplicon sequencing. A constrained canonical analysis approach showed that the oral microbiomes were shaped by the host species when compared to the oral microbiomes of three Odontoceti species obtained in a previous study (Delphinus delphis, Stenella coeruleoalba, and Phocoena phocoena). A total of 9 ASVs, belonging to the genera Campylobacter (2 ASVs), Phocoenobacter (4 ASVs), Psychrobacter (1 ASV), Tenacibaculum (1 ASV), and Terasakiispira (1ASV), contributed exclusively for the pigmy sperm whales clustering. Evaluating these potential microbial signatures from the K. breviceps specimens, we were able to highlight features evidencing high homology with known marine pathogens, such as Actinobacillus delphinicola, Pasteurella skyensis, Tenacibaculum gallaicum, and Te-nacibaculum soleae, thus suggesting a disease association. These should be further explored as mi-crobiota fingerprints towards cetacean population control and biomonitoring.