In vivo acquisition of fosfomycin resistance in Escherichia coli by fosA transmission from commensal flora. In vivo fosA acquisition in Escherichia col

Here we describe the within-host acquisition of fosfomycin resistance in Escherichia coli during oral fosfomycin treatment for chronic aortic bifurcation graft infection. Evidenced by whole genome sequencing, the E. coli bloodstream isolate acquired an extra genetic region containing a fosA gene that originated from Klebsiella variicola, previously isolated in cultures from blood and rectal swab. To our knowledge this is the first description of in vivo transfer of a fosfomycin-inactivating gene between gut commensals and opportunistic pathogens.