TABLE 2.

MICs for NA and C among 40 clinical and reference E. coli isolates, and their NA-resistant derivatives, according to VF content

MIC endpoint (strain)	VF(s) (no. positive, of 40)b	Median MIC (range) (mg/liter) when:		P value(s)c
		VF(s) present	VF(s) absent
NA MIC (parent)	K1 (4)	0.63 (0.38-1.0)	1.0 (0.75-3.0)	0.009
	ExPEC (26)	1.0 (0.38-3.0)	1.25 (1.0-3.0)	0.02
C MIC (parent)	pap genes (13-18)d	0.007 (0.002-0.012)	0.008 (0.004-0.016)	0.005-0.02d
	iha (17)	0.008 (0.002-0.012)	0.008 (0.004-0.016)	0.014
	sat (15)	0.006 (0.002-0.012)	0.008 (0.004-0.016)	0.01
	iutA (17)	0.006 (0.002-0.012)	0.008 (0.004-0.016)	0.005
C MIC (NA-resistant derivativee)	afa/dra (4)	0.45 (0.3-1.0)	0.21 (0.03-1.7)	0.009
	K1 (4)	0.13 (0.03-0.25)	0.24 (0.12-1.7)	0.047

^aafa/dra codes for Dr-binding adhesins; ExPEC is defined by the presence of two or more of the following: papA and/or papC (P fimbriae structural subunit and assembly), sfa/foc (S fimbriae/F1C fimbriae), afa/dra, kpsM II (group 2 capsule), and iutA (aerobactin system). iha codes for putative siderophore adhesin; K1 is a kpsMII variant; sat codes for secreted autotransporter toxin.

^bOnly VFs yielding P values of <0.05 with at least one MIC endpoint are shown. VFs detected in ≥1 isolate but not yielding P values of <0.05 include the following (no. of isolates shown in parentheses): astA, coding for enteroaggregative E. coli heat-stable toxin 1 (2); cdtB, coding for cytolethal distending toxin (3); cnf1, coding for cytotoxic necrotizing factor (5); cvaC, coding for microcin (colicin) V; fimH, coding for type 1 fimbriae (39); focG, coding for F1C fimbriae (5); fyuA, coding for yersiniabactin system (25); H7 fliC, coding for flagellin variant (1); hly, coding for hemolysin (9); ireA, coding for siderophore receptor (6); iroN, coding for siderophore receptor (9); iss, coding for increased serum survival (1); kpsMTIII, coding for group 3 capsule (1); malX, pathogenicity island marker (12); ompT, coding for outer membrane protease T (16); papG allele III, coding for P adhesin variant (7); rfc, coding for O4 lipopolysaccharide synthesis (2); sfaS, coding for S fimbriae (2); traT, which is serum resistance associated (17); and usp, coding for uropathogenic-specific protein (10). Not detected were the following: afaE8, coding for afimbrial adhesin VIII; bmaE, coding for M fimbriae; clpG, coding for CS31A adhesin; F17, coding for F17c fimbriae; gafD, coding for G fimbriae; ibeA, associated with invasion of brain endothelium; K2, kpsMII variant; and papG allele 1, coding for P adhesin variant I.

^cP values determined by Mann-Whitney U test (exact, two-tailed).

^dpapA (n = 18; P = 0.006), papC (n = 18; P = 0.006), papEF (P fimbriae tip pilins: n = 19; P = 0.02), papG (P adhesin; n = 17; P = 0.014), and papG allele II (P adhesin variant; n = 13; P = .005) yielded identical comparative C MIC results (as shown) with the parent strain.

^eNA resistance defined here as an NA MIC of ≥250 mg/liter.