Identificação da microbiota esofágica e sua provável associação com lesões caseosas obstrutivas em tartarugas-verdes (Chelonia mydas)

Abstract

The occurrence of caseous lesion in the esophagus of green turtles (Chelonia mydas) from the coast of Brazil has been described as obstructive and can cause the death of animals. However, its etiology remains unclear. The aim of this study was to characterize the esophageal microbiota of green turtles (C. mydas) from the Brazilian coast and to verify their possible participation in the etiology of caseous lesions. Were used 42 animals, 33 alive and nine naturally dead who presented esophageal lesion, from Anchieta and Piúma, Espírito Santo, in which microbiological tests and morphological evaluation of the esophagus were performed. Were isolated 14 different bacterial agents from healthy animal samples, with prevalence of Pseudomonas aeruginosa (36.36%), Staphylococcus aureus (33.33%), Aeromonas hydrophila (27.27%) and Vibrio alginolyticus (24.24%). In the dead animals, only three distinct agents, S. aureus, A. hydrophila and V. alginolyticus, were isolated. The morphological evaluation revealed a predominance of the lesion at the gastroesophageal junction, with multifocal to coalescent distribution, discrete intensity and absence of obstruction. Ulceration and caseous exudate, inflammatory infiltrate, parasitic eggs and foreign body giant cells were also observed, as well as bacterial lumps and glandular alterations, such as necrosis, adenitis and fragments of adult parasites. There was a positive correlation between bacterial lumps and microbiological test and a negative correlation between bacterial lumps and microbiological test with parasites. It is noted that the esophageal microbiota of C. mydas is predominantly composed of Gram-negative bacteria such as P. aeruginosa, A. hydrophila and V. alginolyticus, in addition to several enterobacteria and Gram-positive bacteria, such as S. aureus and these agents are involved in the etiology of caseous esophagitis.