Table 5.

μg/ml MIC₈₀ values for DHPS variants.

		Primary mutation				Secondary mutation		Double mutation
	R	WT	F17L	S18L	T51M	E208K	KE257_dup	F17L E208K	F17L KE257_dup	T51M E208K*
Sulfacetamide		25	41.7	20.8	12.5	50	41.7	200	133.3	200 – >200
Sulfathiazole		2.6	12.5	4.2	3.1	8.3	8.3	41.7	41.7	83.3
Sulfamethoxazole		4.2	16.7	10.4	6.3	8.3	8.3	50	41.7	66.7
Sulfisoxazole		2.1	6.3	5.2	2.1	6.3	6.3	25	25	58
Sulfapyridine		33.3	100	50	66.7	50	50	200	200 – >200	>200
Sulfadiazine		10.4	25	25	8.3	20.8	20.8	83.3	83.3	200
Dapsone		16.7	20.8	6.3	50	33.3	29.2	50	66.7	200 – >200
Sulfamethoxypyridazine		7.3	25.0	25.0	7.3	12.5	16.7	83.3	83.3	133.3
Sulfadimethoxine		2.6	12.5	4.2	3.6	8.3	8.3	33.3	25	66.7
Sulfadoxine		25	33.3	41.7	12.5	50	41.7	200	83.3	200 – >200
Chloramphenicol		4.2	4.2	3.1	3.1	3.1	3.1	3.1	3.1	3.1
Trimethoprim		1.6	0.065	0.024	0.16	1.6	1.0	0.16	0.20	2.1
$\frac{\text{Sulfamethoxazole}}{\text{Trimethoprim}}$§		$\frac{0.39}{0.021}$	$\frac{0.78}{0.041}$	$\frac{0.33}{0.017}$	$\frac{0.39}{0.021}$	$\frac{0.52}{0.027}$	$\frac{0.65}{0.034}$	$\frac{1.6}{0.082}$	$\frac{1.6}{0.082}$	$\frac{3.1}{0.16}$

MIC₈₀ values reported are an average of three experiments. Apart from T51M/E208K, all mutants were cloned via allelic replacement into an isogenic USA300 AH1263 panel.

^*T51M/E208K values were derived from the COL S. aureus strain (Supplementary Table 1).

^§The SMX/TMP combination MICs at the bottom of the Table represent co-trimoxazole at a ratio of 19:1.