Fosfomycin Resistance in Escherichia coli, Pennsylvania, USA

Fosfomycin resistance in Escherichia coli is rare in the United States. An extended-spectrum beta-lactamase producing E. coli clinical strain identified in Pennsylvania, USA, showed high-level fosfomycin resistance caused by the fosA3 gene. The IncFII plasmid carrying this gene had a structure similar to those found in China, where fosfomycin resistance is commonly described.