Mississippi State University, College of Forest Resources - Sandel Lab
Mississippi State University, College of Forest Resources - Sandel Lab
Dr. Michael W. Sandel
1Department of Wildlife, Fisheries, and Aquaculture, Mississippi State University; 2Department of Biological Sciences, Florida International University; 3Department of Biological Sciences, Mississippi State University; 4Maladies Infectieuses et Vecteurs : Ecologie, Génétique, Evolution et Contrôle (UMR MIVEGEC), Université de Montpellier (UM), Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE); 5Epidémiologie des maladies animales et zoonotiques (UMR EPIA), Université Clermont Auvergne, INRAE, VetAgro Sup; 6Epidémiologie des maladies animales et zoonotiques (UMR EPIA), Université de Lyon, INRAE, VetAgro Sup; 7Department of Entomology, Michigan State University; 8Ecology, Evolution and Behavior Program, Michigan State University; 9AgBioResearch, Michigan State University; 10Department of Osteopathic Medical Specialties; 11Forest and Wildlife Research Center, Mississippi State University
Mycobacterium tuberculosis is responsible for Tuberculosis (Tb), the deadliest infectious disease in human history. Investment in Tb research has guided healthcare interventions that have resulted in a 2% annual reduction in global incidence and mortality since 1990. In contrast, opportunistic non-tuberculous mycobacteria (NTM) infections are increasing worldwide, even among populations served by the world’s most advanced healthcare systems. The simultaneous opposing trends of Tb and NTM disease incidence implies a knowledge gap between the evolutionary ecology of transmissible and environmental mycobacterioses. We sought to narrow this gap by investigating an aquatic NTM species reported from tropical and subtropical regions. Mycobacterium ulcerans is responsible for Buruli ulcer (BU), a necrotic infection of skin and soft tissues that is of substantial public health concern in tropical and sub-tropical regions of the world. The same bacterium is responsible for disease outbreaks in global aquaculture, resulting in economic losses exceeding $1M annually. Previous research identified the macrolide cytotoxin mycolactone as the main virulence factor of M. ulcerans, and the proteins responsible for mycolactone synthesis are encoded by genes on the pMUM plasmid. Previous methods for detecting M. ulcerans used PCR to target genes or repeat regions on the bacterial chromosome. These are efficient methods but not phylogenetically-informative. We describe a pMUM PCR/Sanger sequencing assay that is applicable for environmental surveys, differential diagnosis of BU disease among wild and captive animal populations, and of potential utility in human clinical settings. Molecular sequence data were used to infer a new phylogeny of the M. ulcerans complex, which reveals evidence for intercontinental translocation of bacilli lineages with importance in aquaculture. Though mycobacterial disease in fishes appears to be rare, we caution that the presence of this zoonotic pathogen imparts a need for integrative risk assessment among stakeholders from aquaculture and public health organizations.
1 Matthew E. Scott, 1Kayla M. Fast, 2Alex W. Rakestraw, 3Magdalene Dogbe, 3Heather Jordan, 2 Sophie Picq, 2Joe Receveur, 2Alexandra Bauer, 4Christine Chevillon, 4,5Jean-François Guégan, 2Jennifer L. Pechal, 2,6,7,8M. Eric Benbow, 1,9Michael W. Sandel
1Department of Wildlife, Fisheries, and Aquaculture, Mississippi State University, Mississippi State, MS, USA; 2Department of Entomology, Michigan State University, East Lansing, MI, USA; 3Department of Biological Sciences, Mississippi State University, MS, USA; 4Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), Université de Montpellier (UM), Centre National de la Recherche Scientifique (CNRS), Institut pour la Recherche et le Développement (IRD), Montpellier, France; 5UMR Animal, santé, territoires, risques et écosystèmes, Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE), Centre de coopération internationale en recherche agronomique pour le développement (Cirad), Université de Montpellier (UM), Montpellier, France; 6Ecology, Evolution and Behavior Program, Michigan State University, East Lansing, MI, USA; 7AgBioResearch, Michigan State University, East Lansing, MI, USA; 8Department of Osteopathic Medical Specialties, East Lansing, MI, USA; 9Forest and Wildlife Research Center, Mississippi State University, Mississippi State, MS, USA
The Amazon Rainforest is recognized as one of the most biodiverse ecosystems on Earth, particularly when considering macroorganisms (animals, higher plants, and fungi). Relatively speaking, little attention has been paid to the microbiological diversity within this ecosystem, or to the interactions between macro and microbiological communities. Toward this end, we characterized the role of habitat parameters on the gut microbiome of freshwater fishes in three primary watersheds in French Guiana. We conducted seasonal field expeditions in the Approuague, Sinnamary, and Mana River Basins. We collected small stream fishes in the headwaters, middle tributaries, and coastal lowlands. Specimens were preserved in 95% ethanol and gut tissue was extracted using commercial DNA extraction kits. We used traditional 16S rRNA metabarcoding to determine the microbial composition in the gut. We calculated measures of microbial diversity and conducted multivariate analyses to compare microbiome composition across species, seasons, microhabitats and macrohabitats. This was done for six species across fourteen fish genera at nine sites(n=250). Preliminary results indicate that Characiformes have more diverse microbiomes than Acanthomorpha (cichlids, Poecilia, Rivulus, etc.), on average. Acanthomorpha microbiomes are more often dominated by Betaproteobacteria, whereas Characiformes are more often dominated by Alphaproteobacteria and Gammaproteobacteria. This may represent conserved regulation of the host gut microbiome within respective fish taxa. These data will also be used as a tool to detect the bacteria responsible for neglected tropical diseases (NTDs), potentially including zoonotic pathogens.
1 Hannah Pye, 1Kayla M. Fast, 2Alex W. Rakestraw, 1Heather R. Jordan, 1Manuel Ruiz-Aravena, 1J-Marcus Drymon, 1Michael W. Sandel
1Mississippi State University; 2Florida International University
Mycobacterium ulcerans is an ulcerative disease-causing bacterial species found in aquatic environments around the globe. In humans, M. ulcerans causes Buruli ulcer, but no cases have been reported in the southeastern United States. Lesions associated with M. ulcerans have been observed in Red Drum (Sciaenops ocellatus) near Louisiana and low concentrations of M. ulcerans have been detected in the environment in coastal ecosystems in the southeastern U.S. First, we surveyed the dermal mucosa of fishes from freshwater and brackish ecosystems in the southeastern U.S for M. ulcerans presence. This included 29 species of fish (n = 566) from Alabama, Mississippi, and Louisiana. Second, we determined a baseline of M. ulcerans presence in marine fishes from the Gulf of Mexico. We swabbed the cloacas and gills of fish collected in Deep Sea Fishing Rodeos in Alabama (n = 238) and Mississippi (n = 151). These collections include 38 different species representing both bony and cartilaginous fish. We noted that 7 individuals had skin lesions, and plan to test whether these are correlated with M. ulcerans presence. Using molecular detection methods, we found evidence for diverse and widespread lineages of M. ulcerans, including strains known to cause debilitating human disease such as Buruli ulcer and a novel ecovar. Mycobacterium ulcerans was present in <1.0% of freshwater fish (5/566) and 12.5% of Red Drum (2/16). These data suggest that it will be important to monitor the presence of M. ulcerans and other pathogens in fish of economic and recreational importance.