Table 3. Association of Streptococcus suis serotype 2 STs and srtF and srtG pilus clusters in isolates from North America*.

ST	No. strains	srtF pilus cluster						srtG pilus cluster
		Gene†				Pili expression‡, Sfp1		Gene†			Pili expression, Sgp1‡
		srtF	sfp1	sfp2	sipF			srtG	sgp1	sgp2
1	11	11	11	11	11	11		3	3	3	0
25	36	36	36	36	36	0		36	36	36	36
28	49	49	49	49	49	46		49	49	49	47

*ST, sequence type.
†The presence of the genes was detected by PCR by using primers and conditions described by Takamatsu et al. (13).
‡Expression of pili encoded by the srtF and srtG pilus clusters was performed by Western blotting by using described antibodies directed against the major subunits of these structures (16,17).