Multiple-host sharing, long-term persistence, and virulence of Escherichia coli clones from human and animal household members

Abstract

During a 3-year surveillance, six household members (five humans and the family dog) yielded 14 Escherichia coli clones. Virulence genes, group B2, and having caused cystitis (in the mother or dog) corresponded to colonization endpoints (number of samples, colonies, hosts, and dates). The dog's cystitis clone was the most extensively recovered clone.

FIG. 1.

Distribution of E. coli clones by host over time among five human household members and their pet dog. Each color represents a different unique clone (a total of 14 clones, arbitrarily designated A to L). The width of each rectangle is proportional to the number of colonies accounted for by the particular clone among the total number of colonies analyzed from the particular sample (usually, five colonies per sample). Sequential sampling number (#) and week number, counting from the mother's initial UTI episode, are shown below the chart. Rectangles with heavy black borders indicate symptomatic UTI episodes (mother, sampling 1; dog, sampling 4). Results for samplings 1 to 3 were reported previously (6). The daughters were redesignated here according to age (1 = older, 2 = younger, the reverse of the previously used designations [6]). Gray and white background = humans; buff background = dog.

FIG. 2.

Clone-sharing relationships among six household members at each of six sampling points and overall. A colored line indicates detection of the corresponding clone (see the color code key) in both individuals connected by the line, either concurrently at the same sampling point (top and bottom small boxes for sampling points 1 to 6) or at any time during the study (center large box). F, father; M, mother; S, son; D₁, daughter 1; D₂, daughter 2. Results for samplings 1 to 3 were reported previously (6). Daughters were redesignated here according to age (1 = older, 2 = younger, the reverse of the previously used designations [6]).