Summary of associations of gene targets with different groupings of isolates based on the Pearson Chi-square value (χ2) and the odds ratio (OR).

Empty cells mean no significant association.a Chi-square value. Asterisks indicate the level of significance*** is P** is 0.001* is 0.01b Odds-ratio (OR) and 95% confidence interval (CI).c One quadrant of the 2x2 contingency table contains a zero. For calculation of the odds-ratio the zero is replaced by 1. The given odds ratio value is the minimal value for that specific gene. No confidence interval is calculated.d No statistics were calculated because variable (gene) is a constant (i.e. does not occur among eae-negative isolates).Summary of associations of gene targets with different groupings of isolates based on the Pearson Chi-square value (χ2) and the odds ratio (OR).