Diarrhea and colonization after oral challenge of A. nancymaae with S. flexneri 2a strain 2457T

Treatment (CFU)No. of animalsDiarrheaaColonizationb
No. of casesMean no. of days to onset (range)Mean no. of days to illness (range)% IncidenceMedian no. of days to onsetMedian no. of days of duration (range)
S. flexneri 2a 2457T (5 × 109)8c24 (3–5)5 (2–8)100110 (3–10)
S. flexneri 2a 2457T (5 × 1010)952 (1–4)7 (5–10)d10017.5 (2–10)
S. flexneri 2a 2457T (5 × 1011)98e3 (1–3)5 (2–10)f10018.5 (5–10)
PBS10110.9 (0–9)0
  • a Diarrhea defined as at least one loose-watery stool on at least two consecutive days during the observation period (10 days) postchallenge.

  • b Colonization assessed by plating on HE agar with confirmatory slide agglutination or colony blotting. Negative samples confirmed with ipaH-specific PCR on frozen stool specimens.

  • c One animal excluded from data analysis due to diarrhea for 2 days prior to challenge.

  • d One animal removed from the study on day 6 postchallenge; full duration data not collected.

  • e One animal removed from the study at 2 days postchallenge; excluded from diarrhea incidence data analysis.

  • f P = 0.002 (Mann-Whitney; two-tailed, α = 0.05) compared to PBS control group.