(a) Genetic environment of a chromosomal fosfomycin resistance gene, fosA7, and its neighboring region (∼19.7 kb) in Salmonella Heidelberg ABB07-SB3031. The gene cassettes are not drawn to scale. (b) Alignment generated in T-Coffee of amino acid sequences of the newly identified FosA7 (in bold) with 13 known fosfomycin resistance proteins found in different bacterial species. Asterisk, amino acid residues conserved among the 14 fosfomycin resistance determinants; colon and dots, amino acid substitutions that result in homologous amino acid residues. The protein GenBank accession numbers are FosA7, KKE03230; FosA2, ACC85616; FosA3, AB522970; FosA4, AB908992; FosA5, AJE60855; FosA6, NG051497; FosAPA, AAT49669; FosATN, AAA98399; FosB, ABS73480; FosC, AAZ14834; FosC2, AB522969; FosK, AB917040; FosX, CWV56762; and open reading frame 1 (ORF1), AAP50248. (c) Phylogenetic relationships between 14 fosfomycin determinants, including the newly described FosA7 (boxed) calculated at http://www.phylogeny.fr.