Bacteria richness and antibiotic-resistance in bats from a protected area in the Atlantic Forest of Southeastern Brazil

Abstract

Bats play key ecological roles, also hosting many zoonotic pathogens. Neotropical bat microbiota is still poorly known. We speculate that their dietary habits strongly influence their microbiota richness and antibiotic-resistance patterns, which represent growing and serious public health and environmental issue. Here we describe the aerobic microbiota richness of bats from an Atlantic Forest remnant in Southeastern Brazil, and the antibiotic-resistance patterns of bacteria of clinical importance. Oral and rectal cavities of 113 bats from Carlos Botelho State Park were swabbed. Samples were plated on 5% sheep blood and MacConkey agar and identified by the MALDI-TOF technique. Antibiotic susceptibility tests were performed using Kirby-Bauer's antibiotic disc diffusion technique.We identified 596 isolates at the genus level and tentatively to the species level. Proteobacteria was the most abundant phylum in all the dietary guilds, representing 87% of the total identified samples. The most common bacteria within bat individuals were Escherichia coli, Klebsiella oxytoca and Serratia marcescens, and within bat species were Serratia marcescens, Pseudomonas sp. and Staphylococcus sp. Frugivores presented the most diverse microbiota. In general, the antibiogram results indicated a low occurrence of resistance on eigth potentially pathogenic bacteria species. The resistance to antibiotics found on our samples was related mostly to the intrinsic resistance of the tested species.The low occurrence of resistant bacteria in our samples could be related to the well preserved environment where bats were caught. Once the major causes of resistance-acquiring are related to anthropic activites, the controlled access of tourists on certain regions of the Park seems to be effectively protecting the environment.

Fig 1. Venn-diagram showing the distribution of bacterial taxa from oral swabs of five dietary guilds of bats on Carlos Botelho State Park, São Paulo State.

The number of taxa within each guild is represented in parenthesis. The abundance of each taxa on bat species is presented in the graph, and separated by dietary guilds.

Fig 2. Venn-diagram showing the distribution of bacterial taxa from rectal swabs of five dietary guilds of bats on Carlos Botelho State Park, São Paulo State.

The number of taxa within each guild is represented in parenthesis. The abundance of each taxa on bat species is presented in the graph, and separated by dietary guilds.