. 2010 Apr 5;54(6):2666–2669. doi: 10.1128/AAC.01743-09

TABLE 2.

Resistance gene microarray hybridization results for E. coli isolates having an aminoglycoside resistance phenotype not explained by any genes detected using the oligonucleotide microarray

Isolate	Unexplained resistance phenotype^a	aac(3)-III	aac(6′)-IIa	aac(3)-IVa	aac(3)-IVa	aacC2	aadA1	aadA2	aadA21	aadA5	aph(3′)-Ia	aph4	aphA7	strA	strB
1090	Gentamicin, amikacin							+	+		+		+	+	+
2517	Gentamicin, amikacin										+		+	+	+
2521	Gentamicin, amikacin								+		+		+
2534	Amikacin				+		+	+			+		+	+	+
2538	Amikacin	+				+		+	+		+		+	+	+
2545	Amikacin			+			+	+	+		+	+	+
2550^b	Gentamicin, amikacin									+	+		+	+	+
2551^b	Amikacin	+	+				+	+	+				+	+	+
2577	Gentamicin, amikacin												+	+	+
2612	Amikacin	+	+			+				+	+	+	+	+	+
2614	Amikacin	+				+				+	+		+	+	+

Phenotypic resistance characteristic for which no explanatory gene was detected on the array. All isolates were resistant to the four aminoglycosides, amikacin, gentamicin, kanamycin, and streptomycin, as measured by a standard disk diffusion assay, and all isolates demonstrated a MIC of >32 μg/ml for amikacin and >8 μg/ml for gentamicin. All isolates were PCR positive for the new methyltransferase gene (GenBank accession no. GU201947) described herein.

Isolates 2550 and 2551 were from the same calf fecal sample.