TABLE 3.

Tigecycline MICs determined by different methods, inhibition zone diameter determinations (disc diffusion), and susceptibility categorization using different media for Enterobacter cloacae strains (five replicates for each method with each medium)^a

Medium	E. cloacae 1				E. cloacae 2
	Etest MIC (μg/ml) [modal value (range)]	Disc diffusion zone diam (mm; mean ± SD)b	Broth dilution MIC (μg/ml) [modal value (range)]	Agar dilution MIC (μg/ml) [modal value (range)]	Etest MIC (μg/ml) [modal value (range)]	Disc diffusion zone diam (mm; mean ± SD)b	Broth dilution MIC (μg/ml) [modal value (range)]	Agar dilution MIC (μg/ml) [modal value (range)]
Difco	2 (2-2)*S	16.2 ± 0.8I	2 (2-4)*S	4 (4-8)I	2 (2-3)*S	16.7 ± 0.6I	4 (4-8)I	8 (4-8)R
Merck	2 (2-2)*S	16.5 ± 0.3I	4 (4-8)I	4 (4-4)I	3 (1.5-3)*I	16.4 ± 0.1I	8 (4-8)R	4 (4-4)I
Remel	3 (3-3)*I	15.1 ± 0.6I	2 (2-8)*S	4 (4-8)I	3 (3-3)*I	16.4 ± 0.3I	4 (4-8)I	8 (4-8)R
BBL	3 (3-3)*I	15.9 ± 0.2I	4 (2-4)I	8 (4-8)R	4 (3-4)I	15.3 ± 0.4I	8 (4-8)R	8 (4-8)R
Oxoid	4 (4-6)I	14.7 ± 0.6I	4 (4-8)I	8 (4-8)R	3 (3-4)*I	14.8 ± 0.4I	8 (4-16)R	8 (4-8)R
bioMérieux	4 (3-4)I	15.1 ± 0.5I			4 (4-4)I	14.5 ± 0.3I

^aFor susceptibility determinations according to the FDA guidelines, “S” indicates susceptibility, “I” indicates intermediate susceptibility, and “R” indicates resistance. The FDA MIC susceptibility and resistance breakpoints were ≤2 μg/ml and ≥8 μg/ml, respectively; the FDA disc diffusion zone diameter susceptibility and resistance breakpoints were ≥19 mm and ≤14 mm, respectively. For BSAC/EUCAST susceptibility determinations, the absence of a symbol indicates susceptibility, an asterisk indicates intermediate susceptibility, and underlining indicates resistance. The BSAC/EUCAST MIC susceptibility and resistance breakpoints were ≤1 μg/ml and ≥4 μg/ml, respectively; the BSAC/EUCAST disc diffusion zone diameter susceptibility and resistance breakpoints were ≥24 mm and ≤19 mm, respectively.

^bMean values were rounded up or down to the nearest digit for susceptibility interpretations.