Characterization of the Skin Cultivable Microbiota Composition of the Frog Pelophylax perezi Inhabiting Different Environments

Abstract

Microorganisms that live in association with amphibian skin can play important roles in protecting their host. Within the scenarios of global change, it is important to understand how environmental disturbances, namely, metal pollution, can affect this microbiota. The aim of this study is to recognize core bacteria in the skin cultivable microbiota of the Perez frog (Pelophylax perezi) that are preserved regardless of the environmental conditions in which the frogs live. The characterization of these isolates revealed characteristics that can support their contributions to the ability of frogs to use metal impacted environments. Frog’s skin swabs were collected from P. perezi populations that inhabit a metal-polluted site and three reference (non-metal polluted) sites. Bacterial strains were isolated, identified, and subjected to an acid mine drainage tolerance (AMD) test, collected upstream from a site heavily contaminated with metals, and tested to produce extracellular polymeric substances (exopolysaccharide, EPS). All frog populations had Acinetobacter in their cutaneous cultivable microbiota. Significant growth inhibition was observed in all bacterial isolates exposed to 75% of AMD. EPS production was considered a characteristic of several isolates. The data obtained is a preliminary step but crucial to sustain that the cultivable microbiota is a mechanism for protecting frogs against environmental contamination.

Skin cultivable bacterial of Melanophryniscus admirabilis (admirable red belly toad): the role of bacterial communities on species conservation

“…Enterobacteriaceae was the most abundant cultivable family identi ed in all skin samples of wild M. admirabilis. This result is in concordance with Proença et al, [20] that also showed Enterobacteriaceae was the most dominant cultivable family in skin samples of Perez's frogs (Pelophylax perezi) living in non-contaminated and contaminated rivers from Portugal. Besides, Bacillaceae, Moraxellaceae, and Aeromonadaceae were also observed in Perez's and Panamanian frogs [20,21].…”

“…Bacillus sp., Citrobacter freundii, Janthinobacterium lividum, Pseudomonas sp., Serratia sp. found on amphibian's skin already showed inhibitory activity against Bd fungus [20,24,[33][34][35][36][37][38]. In addition, several bacteria of the amphibian skin act as component of the innate immune system of amphibians, acting as a barrier to pathogen infection and maintaining the species in an environment modulated by anthropic action [20,38].…”

Ecological Factors and Anthropogenic Disturbance May Restructure the Skin Microbiota of Maoershan Hynobiids (Hynobius maoershanensis)

“…Adverse environmental changes resulting from human activities can cause changes in the symbiotic microbial community that can make the host more susceptible to pathogens [34]. Moreover, dysbiosis of the amphibian skin microbiota increases the sensitivity to pathogen infection and decreases skin defense and immune function [35,36]. For example, because integrated pig-fish farming causes pollution in ponds, the high concentration of fecal coliform bacteria in ponds largely reduces the diversity of the anurans skin microbiota, leading to a high proportion of Bd-facilitative bacteria in the skin microbiota and increasing the prevalence of Bd in the frogs [37].…”

“…Analyzing the impact of habitats disturbed by human activity on changes in the host skin microbiota is important for understanding how host-associated symbiotic microbial communities respond to changes in adverse environmental conditions [1]. Information on the skin microbiota of animals can both clarify the relationship between the skin microbiota composition and environmental factors [36] and provide a research basis for future provisioned populations. We studied the skin microbiota of Maoershan hynobiids using 16S rRNA high-throughput sequencing.…”