Environmental microbial colistin resistance in an elderly south Brazilian long-term care facility

Colistin resistance is a global health concern, with antibiotics being the last treatment for Gram-negative bacteria infections. We aimed to identify colistin-resistant enterobacteria on environmental surfaces of a long-term care facility (LTCF) for the elderly in southern Brazil. Samples were collected and screened on MacConkey agar plus colistin, followed by API20E identification and PCR. Two isolates were founded and identified as Klebsiella pneumoniae and Providencia stuartii harboring mcr-1 gene with MICs > 128 µg mL^-1 for colistin. This is the first isolation of microorganisms resistant to colistin in the environment of a LTCF for the elderly in south Brazil, urging monitoring programs to reduce environmental contamination by multiresistant microorganisms.