TABLE 1.

Activities of tetramic acids against strains of S. aureus and S. pyogenes

Organism (no. of strains)	Antibiotic	MIC (μg/ml)
		Range	50%	90%
MSSA (10)a	867	0.4-0.8	0.4	0.8
	1135	0.4-1.6	0.8	0.8
	1137	0.8-1.6	0.8	1.6
	1138	1.6-3.12	1.6	3.12
	1139	0.2-1.6	0.8	1.6
	Reutericyclin	0.1-1.6	0.8	1.6
	Mupirocin	0.05-0.2	0.12	0.2
	Vancomycin	0.4-0.8	0.8	0.8
MRSA (31)b	867	0.2-1.6	0.8	1.6
	1135	0.4-1.6	0.8	1.6
	1137	0.4-1.6	1.6	1.6
	1138	0.4-3.12	3.12	3.12
	1139	0.1-1.6	0.8	1.6
	Reutericyclin	1.6-6.25	3.12	6.25
	Mupirocin	0.1-0.8	0.2	0.4
	Vancomycin	0.2-6.25	0.8	3.12
Mupirocin-	867	0.2-1.6	0.8	1.6
resistant	1135	0.8-3.12	1.6	3.12
MRSA (10)c	1137	0.8-1.6	1.6	1.6
	1138	0.4-6.25	3.12	3.12
	1139	0.8-1.6	0.8	1.6
	Reutericyclin	0.8-3.12	1.6	3.12
	Mupirocin	12.5->200	>200	>200
	Vancomycin	0.2-0.8	0.8	0.8
S. pyogenes (14)d	867	0.024-0.8	0.2	0.8
	1135	0.012-1.6	0.2	0.8
	1137	0.012-1.6	0.2	0.8
	1138	0.05-3.12	0.4	1.6
	1139	0.05-1.6	0.4	0.8
	Reutericyclin	0.012-0.4	0.4	0.4
	Mupirocin	0.012-0.024	0.024	0.024
	Vancomycin	0.05-0.4	0.4	0.4

^aExcept for oxacillin susceptibility, the resistance phenotypes of all recent methicillin-susceptible S. aureus (MSSA) isolates are undetermined.

^bThe MRSA test panel included 10 recent isolates with undetermined resistances except to oxacillin, 3 strains with intermediate vancomycin resistance, 15 strains resistant to clindamycin, 10 strains resistant to ciprofloxacin, 7 strains resistant to gentamicin, 6 strains resistant to tetracycline, 2 strains resistant to trimethoprim-sulfamethoxazole, and 2 strains resistant to linezolid.

^cThis group consists of six high- and four low-level mupirocin-resistant strains.

^dThis group includes two macrolide-resistant strains.