TABLE 2.

Virulence factor profiles among CGA and non-CGA Escherichia coli sewage isolates

Traita	Prevalence of associated trait [no. (%)]		P valuec
	CGA isolates (n = 15)	Non-CGA isolatesb (n = 22)
F10 papA allele	9 (60)	0 (0)	<0.0001
F16 papA allele	6 (40)	0 (0)	0.0022
papEF	15 (100)	3 (14)	<0.0001
papG allele II	6 (40)	1 (4)	0.0113
afa/dra	0 (0)	14 (64)	(<0.0001)
iha	14 (93)	3 (14)	<0.0001
sat	14 (93)	4 (18)	<0.0001
iutA	14 (93)	7 (32)	0.0002
kpsM II	15 (100)	10 (45)	0.0004
ompT	15 (100)	8 (36)	<0.0001

^aOnly those traits for which prevalence differences between CGA and non-CGA isolates were statistically significant (Fisher's exact test; P < 0.05) are shown. Trait definitions: papA, P fimbria structural subunit gene; papEF, P fimbria tip pilus gene; papG allele II, P fimbriae adhesion variant II gene; afa/dra, Dr antigen binding adhesin gene; iha, adhesin/siderophore gene; sat, secreted autotransporter toxin gene; iutA, aerobactin receptor gene; kpsM II, group II capsule gene; and ompT, outer membrane protease T gene. Other traits present in CGA but not significantly different in overall prevalence compared with non-CGA isolates,, included papC (P fimbria assembly), fimH (type 1 fimbria adhesin), fyuA (yersiniabactin receptor), and traT (serum resistance-associated gene). Traits absent from CGA isolates but detected among non-CGA isolates included the F12 papA allele, papG allele III, iroN, K1 kpsM II variant, usp, iss, and malX; however, these differences (CGA versus non-CGA) were not statistically significantly by Fisher's exact test.

^bNon-CGA, TMP-SMZ-resistant control isolates were chosen in a 2:1 ratio to the CGA isolates within each locale, with the exception of San Jose, CA, where only 18 non-CGA, TMP-SMZ resistant isolates were recovered, all of which were used as controls.

^cThe P value in parentheses is for a negative association with CGA.