TABLE 2.

MIC ranges of E. coli ATCC 25922 at 24 and 48 h of incubation

Antimicrobial agent	Incubation time (h)	No. of occurrences at indicated MIC (μg/ml)a																	% of occurrences in rangeb
		<0.004	0.008	0.016	<0.03	0.06	0.12	0.25	0.5	1	2	4	8	>16	32	64	128	256
Gentamicin	24						0	0	0	4	112	60	58	6					97.5
	48						0	0	0	2	103	65	56	14					94.2
Chloramphenicol	24								0	0	2	229	24	0	0				100
	48								0	0	1	84	154	0	0				99.6
Ciprofloxacin	24				235	3	2												NRc
	48				235	3	2												NR
Doxycycline	24				0	0	0	0	1	237	17	0	0						100
	48				0	0	0	0	1	49	190	0	0						99.6
Levofloxacin	24				236	3	1	0	0	0	0	0	0						NR
	48				233	4	3	0	0	0	0	0	0						NR
Rifampin	24	0	0	0	0	0	0	0	0	0	9	25	206	0					96.3
	48	0	0	0	0	0	0	0	0	0	9	15	211	5					96.3
Azithromycin	24						0	0	0	0	4	8	107	121					NR
	48						0	0	0	0	3	8	85	144					NR
Tetracycline	24				0	0	0	0	30	176	34	0	0	0					100
	48				0	0	0	0	0	109	94	37	0	0					100
Streptomycin	24								0	0	0	0	112	126	2	0	0	0	100
	48								0	0	0	0	97	137	6	0	0	0	100
Trim/Sulfad	24					0	0	22	42	12	23	68	38	11	8				NR
	48					0	0	16	31	12	8	35	86	24	12				NR

^aThe absence of a value represents the limit of MIC dilutions tested. Recommended QC ranges are represented in boldface characters.

^bPercentage of results which fall within the recommended range (acceptable limit, ≥95%).

^cNR, no range recommended due to extreme variability or off-scale mode.

^dTrim/Sulfa, trimethoprim-sulfamethoxazole.