Table 3.

Susceptibility to nitrofurantoin according to the Clinical and Laboratory Standards Institute (CLSI) procedure and amino acid substitutions in NfsA, NfsB, or RibE proteins of 29 clinical isolates of Escherichia coli.

Strain	Nitrofurantoin Disk 1	Clinical Category 2	Amino Acid Substitutions in
			NfsA	NfsB	RibE
11	11	R	Ile117Thr Gly126Arg Lys141Glu Gln147Arg Gly187Asp	Truncated at Glu54	None
17	27	S	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu	None
26	24	S	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu	None
66	14	R	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu Arg207His	None
302	14	R	None	Gly66Asp Met75Ile Val93Ala Ala174Glu Arg207His	None
334	15	I	Gln67Leu	Gly66Asp Met75Ile Val93Ala Arg107Cys	Pro55His
381	25	S	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu	None
387	21	S	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu	None
462	14	R	Cys80Arg Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu Gly192Ser	None
632	20	S	Glu58Asp Ile117Thr Lys141Glu Gln147Arg Gly187Asp	Val93Ala	None
751	14	R	Ile117Thr Lys141Glu Gly187Asp Arg203Cys	Gly66Asp Val93Ala Ala174Glu	Val51Ile
752	22	S	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu	None
757	16	I	Glu58Asp Truncated at Gln67	Val93Ala Lys122Arg	None
776	19	S	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu	None
789	24	S	Glu58Asp Ile117Thr Lys141Glu Gln147Arg Gly187Asp	Val93Ala	None
792	25	S	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu	None
795	16	I	His11Tyr Glu58Asp Ile117Thr Lys141Glu Gln147Arg Gly187Asp	Val93Ala	None
797	12	R	Ile117Thr Lys141Glu Gly154Glu Gly187Asp	Leu22Ile Gly66Asp Val93Ala Ala174Glu	Val51Ile
799	13	R	Ile117Thr Lys141Glu Gln147Arg Gly187Asp	Val93Ala	None
802	12	R	Truncated at Gln147	Met75Ile Val93Ala	None
809	28	S	Glu58Asp Ile117Thr Lys141Glu Gln147Arg Gly187Asp	Val93Ala	None
853	20	S	Glu58Asp Ile117Thr Lys141Glu Gln147Arg Gly187Asp	Val93Ala	None
854	16	I	None	Gly66Asp Met75Ile Val93Ala	None
860	20	S	Ile117Thr Lys141Glu Gln147Arg Gly187Asp	Val93Ala	None
871	24	S	Glu58Asp Ile117Thr Lys141Glu Gln147Arg Gly187Asp	Val93Ala	None
872	15	I	Asp19Asn Ser33Arg Ile117Thr Lys141Glu Gly187Asp	Gln44His Gly66Asp Val93Ala Ala174Glu	None
883	13	R	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Phe84Ser Val93Ala Ala174Glu	None
891	23	S	Ile117Thr Lys141Glu Gly187Asp	Gly66Asp Val93Ala Ala174Glu	None
892	10	R	None	Gly66Asp Met75Ile Val93Ala	None

¹ Diameter (in mm) of bacterial growth inhibition halo around the disk with 300 μg nitrofurantoin. ² Clinical categories of each isolate against nitrofurantoin according to CLSI breakpoints (S: susceptible; I: intermediate; R: resistant). None: no amino acid substitutions were found.