. 2017 Oct 1;12(4):362–370.

Table 2.

Inhibition of Biofilm Formation of Staphylococcus aureus Isolates at Six Sub-MICs of the Tested Antibiotics


Isolate	MIC(µg/mL)	1/2MIC	1/4MIC	1/8MIC			1/16MIC	1/32MIC			1/64MIC
				Cefazolin
S.aureus633	128	71^*a	60^*	45^*			57^*	54^*			51^*
S.aureus595	128	66^*	56^*	53^*			46^*	60^*			83^*
S.aureus622	4	14	14	7			-14	7			-7
S.aureus627	128	66^*	43^*	16			36^*	10			33^*
MRSA 33591	128	53^*	25	-8			-6	-16			-28
	Azithromycin
S.aureus633	128	7	-17	-32			-22	12			0
S.aureus595	128	3	-3	0			3	3			16
S.aureus622	128	6	-6	-66^*			-6	0			0
S.aureus627	128	26	20	-6			-23	-76^*			-70^*
MRSA 33591	128	3	-21	-28^*			-57^*	-68^*			-70^*
	Vancomycin
S.aureus633	0.5	-80^*	-48^*	-84^*			-^b	-			-
S.aureus595	0.5	0	0	-52^*			-	-			-
S.aureus622	1	45^*	48^*	54^*			57^*	-			-
S.aureus627	0.5	6	-12	-38^*			-	-			-
MRSA 33591	1	17	-4	-19			-23	-			-
	Oxacillin
S.aureus633	128	45^*	33^*		29		37^*	41^*			33^*
S.aureus595	128	37^*	23^*		30^*		35^*	32^*			32^*
S.aureus622	0.5	31	-26		-52^*		-	-			-
S.aureus627	128	39^*	34^*		19		26	36^*			41^*
MRSA 33591	32	-10	2		-7		15	-66^*			-89^*
					Minocycline
S.aureus633	64	-11	-11		-27		-22	5			-11
S.aureus595	64	8	-22		-34		-28^*	-14			-68^*
S.aureus622	64	50^*	42^*		42^*		39^*	39^*			39^*
S.aureus627	64	48^*	25		13		18	10			15
MRSA 33591	64	66^*	42^*		44^*		27^*	17			21
		% Inhibition of Biofilm Formation
Isolate	MIC(µg/mL)	1/2MIC	1/4MIC	1/8MIC			1/16MIC	1/32MIC		1/64MIC
	Cotrimoxazole
S.aureus633	21.3/106.7	-2	-5	5			-4	20		5
S.aureus595	21.3/106.7	30	-2	-23			-15	-2		-38^*
S.aureus622	0.6/3.3	-49^*	-52^*	-50^*			-18	-21		-29^*
S.aureus627	21.3/106.7	37^*	18	18			9	-20		-2
MRSA 33591	2.6/13.3	57^*	23	9			-7	-19		-3
	Rifampin ^c
S.aureus633	0.06			-
S.aureus595	128	42^*	51^*	15			0	21		-6
S.aureus622	0.06			-
S.aureus627	0.06			-
MRSA 33591	0.06			-
	Clindamycin
S.aureus633	128	50^*	46^*	35^*			29^*	24		20
S.aureus595	128	34^*	42^*	40^*			34^*	25		42^*
S.aureus622	8	27	9	18			27	18		9
S.aureus627	64	15	31	50^*			33	30		49^*
MRSA 33591	128	-83^*	-88^*	0			-9	-19		-23
	Linezolid
S.aureus633	128	37^*	41^*		37^*	22			22	50^*
S.aureus595	128	25	50^*		0	25			0	0
S.aureus622	8	16	28^*		14	-4			4	16
S.aureus627	128	13	41^*		20	30^*			24	26
MRSA 33591	64	54^*	52^*		42^*	42^*			38^*	38^*
	Clarithromycin
S.aureus633	128	32^*	40^*	32^*		29^*			25^*	-14
S.aureus595	128	45^*	44^*	31^*		22			22	11
S.aureus622	128	15	10	-15		-5			-15	-10
S.aureus627	128	73^*	65^*	59^*		30^*			39^*	33^*
MRSA 33591	128	11	-5	14		3			-11	-15

ATCC, American type culture collection

^a*

: P<0.05

^:The ratio of MIC mentioned in the table depends on the MIC of each strain. Some concentrations were excluded because they were not in the range of the tested area (0.06to 128 µg/mL).

^:Asthe range of testing concentrations was started from 0.06 µg/mL, and the sub-MICs of 4 strains for rifampin were less than this concentration, they were not included in this table.