Italy has joined the plasmid-borne colistin resistance club (colistin is the last line of defense against carbapenem-resistant enterobacteriaceae–’CRE’–except when it doesn’t work). From ProMED (boldface mine):
The mcr-1 gene, which encodes transferable resistance to colistin, has been confirmed in commensal _Escherichia coli_ from Italy, in primary production of turkeys.
The 1st confirmed mcr-1-positive isolate is among colistin-resistant isolates detected from the harmonised monitoring programme performed on cecal samples at slaughter in 2014, and aimed at estimating the AMR [antimicrobial resistance] prevalence in major zoonotic (e.g. _Salmonella_, _Campylobacter jejuni_) and indicator commensal bacteria (e.g. _E. coli_), according to the Decision 2013/652/EU….
The 1st isolate with the confirmed mcr-1 gene was whole genome-sequenced in collaboration with the European Union Reference Laboratory for Antimicrobial Resistance (EURL-AR), DTU [Technical University of Denmark]-Food, Denmark. It was a multidrug resistant (SMX-TMP-CIP-TET-CHL-COL-AMP) [sulfamethoxazole-trimethoprim-ciprofloxacin-tetracycline-chloramphenicol-colistin-ampicillin] Sequence Type 30 _E. coli_, also harbouring the Plasmid Mediated Quinolone Resistance (PMQR) gene qnrB19 (CIP MIC [minimal inhibitory concentration] 0.5 mg/L). Further investigation on colistin-resistant isolates from animal primary productions is ongoing.
I haven’t seen the assembly yet online, but hopefully it will arrive. The ciprofloxacin resistance is disconcerting, as ciprofloxacin is often used to treat urinary tract infections. The sulfamethoxazole-trimethoprim-tetracycline-chloramphenicol resistance phenotype is commonly found in agricultural E. coli and Salmonella isolates and is often plasmid-borne.
I still find it amazing that mcr-1 still isn’t found in the U.S., although, as best as I can tell, colistin isn’t used very frequently and only in specific circumstances (where other drugs can also be used). It wouldn’t hurt to institute a colistin ban in agriculture as this drug is the final option to treat CRE.