Novel diversity of bacterial communities associated with bottlenose dolphin upper respiratory tracts

Abstract

Respiratory illness is thought to be most the common cause of death in both wild and captive populations of bottlenose dolphins (Tursiops truncatus). The suspected pathogens that have been isolated from diseased animals have also been isolated from healthy individuals, suggesting they may be part of the normal flora. Our current understanding of the bacteria associated with the upper respiratory tract (URT) of bottlenose dolphins is based exclusively upon culture-based isolation and identification. Because < 1% of naturally occurring bacteria are culturable, a substantial fraction of the bacterial community associated with the dolphin URT remains to be described. The dolphin URT microbiota revealed by sequencing of bacterial 16S rDNA exhibits almost no overlap with the taxa indicated in culture-based studies. The most abundant sequences in our libraries were similar among all of our study animals and shared the greatest homology to sequences of bacteria belonging to the genera Cardiobacterium, Suttonella, Psychrobacter, Tenacibaculum, Fluviicola and Flavobacterium; however, they were sufficiently different from database sequences from both cultured and uncultured organisms to suggest they represent novel genera and species. Our findings also demonstrate the dominance of three of the four bacterial phyla that dominate other mammalian microbiomes, including those of humans, and show tremendous diversity at the species/strain level, suggesting tight coevolution of the dolphin host and its URT bacterial community.

An Economical Custom-Built Drone for Assessing Whale Health

“…Taxa names correspond to the highest taxonomic level identification, full taxonomies are present in Supplementary Tables 3-6) only the top taxa by abundance are shown in the legend. (Johnson et al, 2009;Lima et al, 2012). These findings may indicate that these genes are part of the normal microflora of dolphins, whilst presence in whales until now was unknown.…”

Isolation of culturable aerobic bacteria and evidence of Kerstersia gyiorum from the blowhole of captive Yangtze finless porpoises

“…Because of the critically endangered status of the YFPs, we have used a relatively convenient and non-invasive method to collect blowhole samples from captive YFPs, to provide the first preliminarily baseline record of the normal respiratory tract bacterial microbiota. The three bacterial phyla (Proteobacteria, Firmicutes and Bacteroidetes) found in the blowhole of YFPs are also commonly found in the respiratory tracts of other marine mammals, such as bottlenose dolphins (Tursiops truncatus) (Johnson et al 2009;Morris et al 2011) and manatees (Trichechus manatus manatus) (Vergara-Parente et al 2003). However, the relative proportions of these phyla differed among mammals.…”

“…However, the relative proportions of these phyla differed among mammals. Interestingly, Actinobacteria (1 % of our total sequences) is also not commonly found in the respiratory tracts of bottlenose dolphins (Johnson et al 2009). The blowhole bacterial species diversity of the captive YFPs tended to be lower.…”

“…Recently, novel non-invasive sampling strategies, for the collection of exhaled breath condensate or 'blow', have been used successfully to collect samples from many free-ranging and captive cetaceans (Acevedo-Whitehouse et al 2010;Johnson et al 2009;Lima et al 2012). This strategy could be used as a monitoring tool for microbial populations associated with the cetacean respiratory system.…”

“…Often, those organisms are present as part of the normal microbiota and only become opportunistic pathogens when the animals are stressed, immunosuppressed, or under antimicrobial treatment (Avalos-Téllez et al 2010;Johnson et al 2009). This is true for captive or rescued YFPs in China as well, where these illnesses are rarely diagnosed in time for a successful treatment.…”