Figure 2. Engineered native E. coli can engraft in the luminal environment.

(A) Long-term colonization after gavage with 10¹⁰ CFUs of E. coli MG1655 and E. coli Nissle 1917 (two lab-strain E. coli often used as chassis for function delivery), as well as EcAZ-2 in non-antibiotic-treated CR-WT mice housed in a low-barrier, non-sterile facility after a single gavage. Sample measures in the gray area denote mice where the bacteria were not detectable at a limit of detection of Log₁₀ of 2.

(B) Colonization at 110 days (Fisher’s exact test; 4–8 mice/condition).

(C) Colonization in co-housed mice housed in a low-barrier, non-sterile facility after a single gavage, where one mouse received 10¹⁰ CFUs of EcAZ-2 and the other received vehicle via oral gavage. Arrow indicates change in stool collection protocol where mice were separated from their cage mates 24 h prior to their weekly stool collection. Mice were returned to their cage mates right after stool collection. Thus, although uncolonized mice are exposed to EcAZ-2 through coprophagia, the level is not sufficient to lead to engraftment.

(D) Colonization after gavage of different initial doses of EcAZ-2 in non-antibiotic-treated CR-WT mice housed in a low-barrier, non-sterile facility after a singlegavage (n = 5).

(E) Colonization after gavage of 10¹⁰ CFUs of EcAZ-2 in the stool of non-antibiotic-treated CR-WT mice in an SPF facility on a stable diet (10% fat) or on diets with different macronutrient profiles (non-fat diet [NFD] or high-fat diet [HFD]). Diet was changed 4 days post-gavage (4 mice/condition).

(F) Colonization after gavage of 10¹⁰ CFUs of EcAZ-2 or EcAZ-2^BSH+ in non-antibiotic-treated CR-WT mice housed in an SPF facility (4–12 mice/condition).

(G) Colonization after gavage of 10¹⁰ CFUs of EcAZ-2 or EcAZ-2^IL10+ in non-antibiotic-treated CR-WT mice housed in an SPF facility (4 mice/condition).

(H) Colonization of gastrointestinal tract in CR-WT mice 3 months after a single gavage in an SPF facility. Sample measures in the gray area denote mice where the bacteria were not detectable at a limit of detection of Log₁₀ 2. (4 mice/condition.)

(I) Colonization of EcAZ-2 and EcAZ-2^IL10+ in the gastrointestinal tract of CR-WT mice housed in an SPF facility 79 days after gavage (same mice depicted in Figure 2E; 5/condition).

All error bars indicate standard error of the mean. Samples that were not detectable were excluded from mean and standard error of mean calculations. The marker covers some error bars in (E), (F), and (G).

See also Figure S2.