TABLE 1.

Antimicrobial susceptibility of S. pyogenes isolates with different macrolide resistance genotypes in Germany from 1999 to 2000

S. pyogenes type (n)	Antibiotic	MIC (μg/ml)a			No. (%) of strainsb
		Range	50%	90%	Susceptible	Intermediate	Resistant
All strains (381)	Penicillin G	≤0.016-0.06	≤0.016	≤0.016	381 (100)	0 (0)	0 (0)
	Erythromycin A	≤0.03-≥32	≤0.03	4	326 (85.6)	1 (0.3)	54 (14.2)
	Clarithromycin	≤0.03-≥32	≤0.03	2	327 (85.8)	5 (1.3)	49 (12.9)
	Roxithromycinc	≤0.03-≥32	0.125	8	NDd	ND	ND
	Azithromycin	≤0.03-≥32	0.06	8	324 (85.0)	2 (0.5)	55 (14.4)
	Clindamycin	≤0.03-≥32	≤0.03	0.25	377 (98.9)	0 (0)	4 (1.1)
	Levofloxacin	0.125-≥32	0.5	0.5	380 (99.7)	0 (0)	1 (0.3)
	Telithromycinb	≤0.03-≥32	≤0.03	≤0.03	379 (99.5)	0 (0)	2 (0.5)
Erythromycin A resistant (54)	Penicillin G	≤0.016-0.06	≤0.016	≤0.016	54 (100)	0 (0)	0 (0)
	Erythromycin A	1-≥32	8	≥32	0 (0)	0 (0)	54 (100)
	Clarithromycin	0.5-≥32	4	≥32	0 (0)	5 (9.3)	49 (90.7)
	Roxithromycinc	1-≥32	16	≥32	ND	ND	ND
	Azithromycin	1-≥32	8	≥32	0 (0)	1 (1.9)	53 (98.1)
	Clindamycin	≤0.03-≥32	0.06	0.25	50 (92.6)	0 (0)	4 (7.4)
	Levofloxacin	0.125-1	0.5	0.5	54 (100)	0 (0)	0 (0)
	Telithromycinc	≤0.03-≥32	0.25	0.5	52 (96.3)	0 (0)	2 (3.7)
mef(A) positive (30)	Penicillin G	≤0.016	≤0.016	≤0.016	30 (100)	0 (0)	0 (0)
	Erythromycin A	1-16	8	16	0 (0)	0 (0)	30 (100)
	Clarithromycin	0.5-16	4	8	0 (0)	1 (3.3)	29 (96.7)
	Roxithromycinc	1-32	16	32	ND	ND	ND
	Azithromycin	1-32	8	16	0 (0)	1 (3.3)	29 (96.7)
	Clindamycin	≤0.03-0.25	≤0.03	0.25	30 (100)	0 (0)	0 (0)
	Levofloxacin	0.125-1	0.5	0.5	30 (100)	0 (0)	0 (0)
	Telithromycinc	≤0.03-1	0.25	0.5	30 (100)	0 (0)	0 (0)
erm(A) positive (17)	Penicillin G	≤0.016-0.03	≤0.016	≤0.016	17 (100)	0 (0)	0 (0)
	Erythromycin A	2-≥32	4	8	0 (0)	0 (0)	17 (100)
	Clarithromycin	0.5-≥32	1	8	0 (0)	4 (23.5)	13 (76.5)
	Roxithromycinc	2-≥32	8	32	0 (0)	0 (0)	17 (100)
	Azithromycin	2-≥32	16	32	0 (0)	0 (0)	17 (100)
	Clindamycine	≤0.03-0.25	0.06	0.25	17 (100)	0 (0)	0 (0)
	Levofloxacin	0.25-1	0.25	0.5	17 (100)	0 (0)	0 (0)
	Telithromycinc	≤0.03	≤0.03	≤0.03	17 (100)	0 (0)	0 (0)
erm(B) positive (7)	Penicillin G	≤0.016	≤0.016	≤0.016	7 (100)	0 (0)	0 (0)
	Erythromycin A	8-≥32	≥32	≥32	0 (0)	0 (0)	7 (100)
	Clarithromycin	1-≥32	≥32	≥32	0 (0)	1 (14.3)	6 (85.7)
	Roxithromycinc	4-≥32	≥32	≥32	0 (0)	0 (0)	7 (100)
	Azithromycin	8-≥32	≥32	≥32	0 (0)	0 (0)	7 (100)
	Clindamycin	0.25-≥32	≥32	≥32	3 (42.9)	0 (0)	4 (57.1)
	Levofloxacin	0.25-0.5	0.25	0.5	7 (100)	0 (0)	0 (0)
	Telithromycinc	≤0.03-≥32	0.5	≥32	5 (71.4)	0 (0)	2 (28.6)

^a50% and 90%, MIC₅₀ and MIC₉₀, respectively.

^bBreakpoints: penicillin G, intermediate, 0.1 to 1 μg/ml, resistant, ≥2 μg/ml; erythromycin A, intermediate, 0.5 μg/ml, resistant, ≥1 μg/ml; clarithromycin, intermediate, 0.5 μg/ml, resistant, ≥1 μg/ml; azithromycin, intermediate, 1 μg/ml, resistant, ≥2 μg/ml; clindamycin, intermediate, 0.5 μg/ml, resistant, ≥1 μg/ml; and levofloxacin, intermediate, 4 μg/ml, resistant, ≥8 μg/ml (11).

^cRoxithromycin breakpoints are not NCCLS approved. For telithromycin breakpoints of ≤1 μg/ml, ≥4 μg/ml was used (8).

^dND, no data.

^eAll strains were inducibly clindamycin resistant (Table 2).