FIG 1.

Prevalence of FQ-R E. coli variants among clinical isolates and human volunteers. (A) Clinical isolates (6,569) at the MVAMC. (B) Fecal surveillance subjects (MVAMC veterans and their household members). H30R, prevalence of the ST131-H30R subclone; ST1193, prevalence of ST1193-H64; ST1193/FQ-R, prevalence of ST1194-H64 among FQ-R E. coli clinical isolates (A) or FQ-R E. coli-colonized subjects (B). P values not preceded by Δ are for the respective curve or curve segment’s fit to a chi-squared test for linear trend; those preceded by Δ are for the change in slope at the inflection point, according to multivariable logistic regression analysis. The vertical lines mark inflection points used to define curve segment boundaries (i.e., ST1193 and ST1193/FQ-R) for analyses of segmental slope and change in slope. Curves without a vertical line (i.e., FQ-R and H30R) were analyzed in total. P values are shown where P is less than 0.10. NS, nonsignificant (P ≥ 0.10). Numbers of isolates (top) or subjects (bottom) per year are shown below the x axis.