Fosfomycin Resistance in Escherichia coli, Pennsylvania, USA

Abstract

Fosfomycin resistance in Escherichia coli is rare in the United States. An extended-spectrum β-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.

Keywords: 16S rRNA methyltransferase; ESBL; Escherichia coli; Pennsylvania; United States; antimicrobial resistance; bacteria; extended-spectrum β-lactamase; fosA3 gene; fosfomycin resistance; glutathione S-transferase; plasmids.

Figure 1

Comparative analysis of fosA3-carrying IncFII plasmids pYHCC with pXZ. Open reading frames are indicated by arrows and colored according to their putative functions: magenta arrows indicate genes involved in replication; blue arrows indicate genes associated with plasmid conjugal transfer. Brown arrows indicate genes involved in plasmid stability; red arrows indicate antimicrobial drug resistance genes; green arrows indicate accessory genes of mobile elements; gray arrows indicate other backbone genes and inserted foreign genes. Light blue shading indicates shared backbone regions with a high degree of homology. MRR, multidrug resistance region.

Figure 2

EcoRI restriction profile of fosA3-carrying plasmids from a woman in Pennsylvania, USA, who was colonized with fosfomycin-resistant Escherichia coli. Lanes M, lambda DNA/HindIII marker; lane 1, February 2011 (YD472); lane 2, March 2008; lane 3, June 2007 (ECRB1); lane 4, April 2008; lane 5, January 2008. Values on the left are in kilobases.