INTRODUCTION
The global emergence and rapid dissemination of mobile phosphoethanolamine transferase mcr genes, responsible for transferable colistin resistance in Enterobacterales, is a public health concern (El-Sayed Ahmed et al., 2020; Wang et al., 2020). In this regard, since the first report of the mcr-1 gene, in 2016, novel alleles including mcr-2 , mcr-3 , mcr-4 ,mcr-5 , mcr-6 , mcr-7 , mcr-8 , mcr-9 andmcr-10 have been globally identified (El-Sayed Ahmed et al., 2020; Liu et al., 2016; Wang et al., 2020). Worryingly, the occurrence of mcr genes has been documented in critical-priority extended-spectrum β-lactamase (ESBL)-producing pathogens, most isolated from humans and food-producing animals (El-Sayed Ahmed et al., 2020; Liu et al., 2016; Wang et al., 2020). In this study, we report the emergence of mcr-9.1 in an ESBL-producing Enterobacter kobeiinfecting a free-living Franciscana dolphin (Pontoporia blainvillei ), threatened with extinction, in Brazil. Additionally, an epidemiological landscape on global distribution of MCR-9-producing Enterobacterales circulating at human-animal interface is presented.