TABLE 1.

Comparison of phenotypes and genotypes of erythromycin-resistant GAS isolates^a

Phenotype^b	Genotype	No. of isolates	MIC (μg/ml)
			Erythromycin		Clindamycin
			90%	Range	90%	Range
M	mefA	33	32	8-32	0.06	0.06-0.125
iMLS_B	ermB	1		≥1,024		0.25
iMLS_B	ermTR	8	≥1,024	4-≥1024	0.25	0.06-0.5
cMLS_B	ermB	5	≥1,024	256-≥1024	512	1-512
Unknown		2		≥1,024		0.06-0.125

↵a A total of 49 isolates were tested.
↵b Abbreviations: M, efflux; iMLS_B, inducible MLS_B resistance; cMLS_B, constitutive MLS_B resistance.