Identification of bacteria present in ulcerative stomatitis lesions of captive sea turtles Chelonia mydas.

Anthropogenic activities, predation, and diseases have contributed to a decrease in the sea turtle population in recent years. Ulcerative stomatitis is a condition that occurs in both wild and captive populations. The etiology of this condition is associated with bacteria such as E. coli, Citrobacter diversus, Klebsiella spp., Pseudomonas spp., Flavobacter calcoaceticus, Staphylococcus spp., and Flavobacterium spp. Some of these microorganisms are part of the oral microbiota of turtles, but alterations in the immune response can disturb the homeostatic relationship and cause an increase in the population of microorganisms, which in turn can cause disease. This work presents results on the isolation and identification of bacteria present in ulcerative stomatitis lesions in captive C. mydas turtles. Oral mucosa samples from 20 clinically healthy turtles and ten animals with ulcerative stomatitis lesions were studied. The samples were cultivated in enriched and differential media, and the identification was made using an automated method. The results showed a great diversity of bacteria in animals with ulcerative stomatitis with a higher prevalence of S. lentus and C. braakii was higher (60 and 50%, respectively) than in healthy animals. E. faecium was identified in 40% of diseased animals and 55% healthy animals. Turtles in this study had a diverse oral microbiota, and S. lentus and C. braakii may be involved in the etiopathogenesis of ulcerative stomatitis.

Characterisation of the green turtle's leukocyte subpopulations by flow cytometry and evaluation of their phagocytic activity.

Phagocytosis is a fundamental aspect of innate immunity that is conserved across many species making it a potentially useful health-assessment tool for wildlife. In non-mammalian vertebrates, heterophils, monocytes, macrophages, melanomacrophages, and thrombocytes all have phagocytic properties. Recently, B lymphocytes from fish, amphibians, and aquatic turtles have also showed phagocytic capacity. Phagocytes can be studied by flow cytometry; however, the use of this tool is complicated in reptiles partly because nucleated erythrocytes complicate the procedure. We separated green turtle leukocytes by density gradient centrifugation and identified subpopulations by flow cytometry and confocal microscopy. Additionally, we assessed their ability to phagocytize Fluorspheres and Ovoalbumin-Alexa. We found that heterophils and lymphocytes but not monocytes could be easily identified by flow cytometry. While heterophils from adults and juvenile turtles were equally able to phagocytize fluorspheres, adults had significantly more phagocytic ability for OVA-Alexa. Lymphocytes had a mild phagocytic activity with fluorospheres (27-38 %; 39-45 %) and OVA-Alexa (35-46 %; 14-22 %) in juvenile and adult green turtles, respectively. Confocal microscopy confirmed phagocytosis of fluorospheres in both heterophils and lymphocytes. This provides the first evidence that green turtle lymphocytes have phagocytic activity and that this assay could potentially be useful to measure one aspect of innate immunity in this species.