Composition of the cutaneous bacterial community in amphibians in the Western region of Pará, Amazon, Brazil

Abstract

The cutaneous tissue of amphibians is fundamental in many aspects of their lives. The natural characteristics of an amphibian's skin provide an ideal microenvironment for the growth of diverse microorganisms that assist in many important processes for hosts. Therefore, the present study aimed to characterize the cultivable cutaneous microbiota of amphibians sampled in the Santarém region, Western of Pará, Amazonia, Brazil. For this, the amphibians were captured in active searches at night, between the months of November 2017 to April 2019. The cutaneous material was collected by smear in the dorsoventral region of the animal, using a swab soaked in 0.85% saline until dilution 10-3, and cultured in Petri dishes containing PCA medium. Subsequently, the isolation of the colonies was carried out according to the bacterial morphotypes and the identification of the strains was carried out using a biochemical key to identify until the lowest taxonomic level. Two species of amphibians were captured, totaling 25 individuals, being 15 specimens of Rhinella major and 10 individuals of Rhinella marina. 101 bacterial strains were identified and of these 94% were Gram-positive bacteria. The most representative bacterial genera in both amphibian species were Corynebacterium, Lactobacillus and Mycobacterium. Although some genera of bacteria identified in this study have species that are characterized as potential pathogens, there was no evidence that they were causing damage to the animals studied. Thus, it is important that further studies are carried out with the aim of sublimating and inspecting the amphibian microbiota.