TABLE 1.

Correlation between presence of HPI, production of Ybt, and affiliation to each of the phylogenetic groups of E. coli

Phylogenetic group (no. of strains)	Presence of HPI			Ybt production
	No. of strains	CCa	P	No. of strains	CCa	P
A (20)	7	−0.37	<0.001	5	−0.31	0.009
B1 (23)	11	−0.24	0.032	5	−0.40	0.008
B2 (37)	34	0.50	<0.001	32	0.58	<0.001
D (2)	2	0.31	NSb	2	0.15	NS

^aCorrelation coefficient (CC) measured by Spearman rank order correlation represents the strength of correlation, with the maximum value for positive association at 1 and that for negative association at −1.

^bNS, not statistically significant.