The chiroptera gut microbiota: evidence for bifidobacteria presence in Rousettus aegyptiacus

Bifidobacteria represent one of the main bacterial groups occurring in the gut of primates and other animals and are well known for their positive role on host health. Moreover, bifidobacteriaceae are used in coevolution studies since they are maintained within host lineages across hundreds of thousands of host generations. Therefore, the discovery of bifidobacterial diversity in the gastrointestinal tract together with the isolation and characterization of novel bacterial taxa in different hosts is essential. Until now no evidence has been reported about the occurrence of bifidobacteria in bats which are a crucial part of the ecosystem and are ecologically and economically advantageous to humans especially frugivorous ones. This study aimed at the investigation of bifidobacteria in bats belonging to Rousettus aegyptiacus species which were born in Egypt and hosted in Natura Viva Garda Zoological Park (Bussolengo, Verona, Italy). Faecal samples were serially diluted and plated on selective medium MRS supplemented with 0.05 % (w/v) cysteine, 100 mg/l norfloxacin, 2 mg/l cycloheximide, 50 mg/l mupirocin and 1 ml/l acetic acid. Strains were typed by BOX-PCR. Representative isolates of each cluster were identified sequencing 16S rRNA gene and studied for phylogenetical relationship with other Bifidobacteriaceae. Similarities among profiles were calculated by clustering the Pearson‟s correlation matrix using UPGMA algorithm. A total of 13 bifidobacteria were isolated and two of them belonged to new bifidobacterial species according to 16S rRNA gene analysis. The majority of strains revealed a phylogenetic relationship with bifidobacteria isolated from non-human primates. This evolutive link of bifidobacterial microbiotas between bats and non-human primates will be further investigated studying bifidobacteria characterizing Rousettus aegyptiacus bats from Egypt in order to offer new insights about bats origin.