TABLE 5.

Prevalence of SAg genes among emm-1 and emm-28 noninvasive and invasive isolates during study periods A and B

SAg gene	Prevalence (%)a
	emm-1			emm-28
	Noninvasive, period A (n = 27)	Invasive		Noninvasive, period A (n = 31)	Invasive
		Period A (n = 17)	Period B (n = 48)		Period A (n = 16)	Period B (n = 24)
speA	96	94b	67b	10	0b	38b
speC	11	24	42	81	100b	58b
speH	7	6	2	13	38b	4b
ssa	0c	35b,c	8b	6	19	29

^aThe GAS isolate may carry multiple SAg genes. Period A, 1 January to 31 October 2001; period B, 1 November 2001 to 1 August 2002.

^bP < 0.05 by comparison of invasive isolates between period A and B, as determined by the chi-square test.

^cP < 0.05 by comparison of invasive and noninvasive isolates in period A, as determined by the chi-square test.