. 1999 Sep;37(9):2952–2961. doi: 10.1128/jcm.37.9.2952-2961.1999

TABLE 2.

Comparison of susceptibility testing methods to mecA gene analysis for 58 CoNS isolates

Method	Medium	Incubation temp (°C)	Incubation time (h)	No. of isolates					Sensitivity (%)	Specificity (%)	No growth on control
Method	Medium	Incubation temp (°C)	Incubation time (h)	mecA positive	mecA negative	S^a	I^a	R^a	Sensitivity (%)	Specificity (%)	No growth on control
Agar dilution	0% NaCl	30	24	27	27	41^b/34^c		13^b/20^c	48.1^b/59.3^c	100^b/85.2^c	4
			48	29	27	42^b/36^c		14^b/20^c	48.3^b/62.1^c	100^b/96.3^c	2
		35	24	29	28	43^b/36^c		14^b/21^c	48.3^b/65.5^c	100^b/92.9^c	1
			48	30	28	40^b/35^c		18^b/23^c	60.0^b/70.0^c	100^b/92.9^c	0
	2% NaCl	30	24	28	27	34^b/31^c		21^b/24^c	75.0^b/85.7^c	100^b/100^c	3
			48	29	28	34^b/32^c		23^b/25^c	79.3^b/86.2^c	100^b/100^c	1
		35	24	30	28	39^b/35^c		19^b/23^c	63.3^b/76.7^c	100^b/100^c	0
			48	30	28	35^b/30^c		23^b/28^c	76.7^b/93.3^c	100^b/100^c	0
	4% NaCl	30	24	26	26	28^b/27^c		24^b/25^c	92.3^b/92.3^c	100^b/96.1^c	6
			48	29	28	32^b/31^c		25^b/26^c	86.2^b/86.2^c	100^b/96.4^c	1
		35	24	29	27	31^b/30^c		25^b/26^c	86.2^b/89.7^c	100^b/100^c	2
			48	30	28	28^b/28^c		28^b/30^c	96.7^b ^d/96.7^c	96.4^b ^d/96.4^c	0
Disk diffusion	Difco	35	24	29	27	22	6	28	90.0	74.1	2
			48	30	27	20	4	33	93.3	66.7	1
	BBL	35	24	29	27	23	2	31	86.2	74.1	2
			48	29	27	20	3	33	93.1	70.4	2
Agar screen
Swab inoculation	Remel	35	24	30	28	46		12	40.0	100	—^e
			48	30	28	33		25	83.3	100	—^e
	Difco	35	24	29^f/27^g	27^f/23^g	27^f/35^g		29^f/14^g	93.1^f/51.8^g	92.6^f/100^g	2^f/1^g
			48	30^f/27^g	27^f/23^g	25^f/22^g		32^f/26^g	100^f/96.3^g	92.6^f/100^g	1^f/1^g
Spot inoculation	Remel	30	24	30	28	44		14	46.7	100	—^e
			48	30	28	39		19	63.3	100	—^e
		35	24	30	28	38		20	66.7	100	—^e
			48	30	28	38		20	66.7	100	—^e
	Difco	30	24	26	26	30		22	84.6	100	6
			48	29	28	33		24	82.3	100	1
		35	24	29	27	36		20	70.0	100	2
			48	30	28	32		26	83.3	96.4	0

S, susceptible; I, intermediate; R, resistant.

Susceptibility breakpoint, ≤2 μg/ml.

Susceptibility breakpoint, ≤1 μg/ml.

One isolate was interpreted as susceptible but was mecA positive; this isolate was interpreted as resistant by the agar screen swab inoculation method with Difco medium prepared in-house (60 colonies at 0.6 μg/ml; 20 colonies at 6.0 μg/ml).

No control plate available.

Oxacillin concentration, 0.6 μg/ml.

Oxacillin concentration, 6.0 μg/ml.