Pansusceptible Escherichia coli isolates obtained from faeces of free-ranging Baird's tapirs (Tapirus bairdii) suggests a low selective pressure for resistance determinants in the northwestern region of the Talamanca Mountain Range, Costa Rica

Objectives: The main objective of this study was to analyse the antimicrobial susceptibility profile of Escherichia coli isolates obtained from faecal samples of free-ranging Baird's tapirs (Tapirus bairdii) in the northwestern region of the Talamanca Mountain Range, Costa Rica.

Methods: Faecal samples were collected by opportunistic search of the study area from February-September 2017 during seven field expeditions. Escherichia coli isolates were recovered using selective and differential MacConkey agar medium and were subjected to biochemical identification and antimicrobial susceptibility testing using a VITEK^®2 Compact automated system and the AST-N279 card.

Results: A total of 60 E. coli isolates were obtained from 63 faecal samples. Following evaluation of nine different antimicrobial classes, 98% (59/60) of the isolates were characterised as pansusceptible; only 1 isolate presented resistance to nalidixic acid.

Conclusion: We propose that the commensal intestinal microbiota of free-ranging Baird's tapirs in this area remains isolated from antibiotic selective pressure, probably because seven different protected areas converge, thus giving a possible low anthropogenic activity to the region.