Lactobacillus acidophilus attenuates polyethylene glycol-induced susceptibility to Citrobacter rodentium infection via microbiota modulation

Figure 1 Polyethylene glycol increase the Citrobacter rodentium load and virulence. A: Mice of the two groups were gavaged with water or polyethylene glycol 1 day prior to the infection of Citrobacter rodentium (CR). Fecal pallets were collected at day 3, 5, 7, 8, and 9; B: CR load in the feces over the indicated time; C: CR load of the intestines tissue and systemic dissemination of CR; D and E: The mRNA expression of the Ler and Tir in the fecal. Data are representative of at least two independent experiments. Data are shown as mean ± SD. ^cP < 0.001. CR: Citrobacter rodentium; CFUs: Colony-forming units; PEG: Polyethylene glycol.

Figure 2 Polyethylene glycol aggravates Citrobacter rodentium induced colitis. A and B: Colon length at day 12 post Citrobacter rodentium infection; C and D: Representative hematoxylin and eosin staining (20 ×) and pathological score of the inflamed colon epithelium. Data are representative of at least two independent experiments. Data are shown as mean ± SD. PEG: Polyethylene glycol.

Figure 3 Polyethylene glycol results in an infection window of 14 days. A: Mice were gavaged with polyethylene glycol 7-day before infection with Citrobacter rodentium (CR); B: CR load of the feces; C and D: Colon length; E and F: Representative hematoxylin and eosin staining (20 ×) and pathological score of the inflamed colon epithelium; G and H: The mRNA expression of the tumor necrosis factor-α and interferon-γ of the inflamed colon; I: Mice were gavaged with polyethylene glycol 14-day before infection with CR; J: CR load of the feces; K and L: Representative hematoxylin and eosin staining (20 ×) and pathological score of the inflamed colon epithelium; M and N: The mRNA expression of the tumor necrosis factor-α and interferon-γ of the inflamed colon. Data are representative of at least two independent experiments. Data are shown as mean ± SD. CR: Citrobacter rodentium; CFUs: Colony-forming units; PEG: Polyethylene glycol; TNFα: Tumor necrosis factor-α; IFNγ: Interferon-γ.

Figure 4 Gut microbiota dysbiosis play an essential role in the polyethylene glycol relative infection. A: Principal coordinate analysis (PCoA) of fecal microbiota pre-polyethylene glycol (PEG) and 1 day post PEG; B-D: Shannon, Chao, and ACE indices of operational taxonomic unit levels of fecal microbiota; E: LDA score for differences between pre-PEG and 1 day post PEG; F-I: Relative abundance of Lactobacillus, Akkermansia, Escherichia-Shigella and Alistipes on genus levels; J: Principal coordinate analysis of fecal microbiota pre-PEG, 1 day post PEG, 3-day post PEG, 7-day post PEG and 14-day post PEG; K-M: Shannon, Chao, and ACE indices of operational taxonomic unit levels of fecal microbiota pre-PEG, 1 day post PEG, 3-day post PEG, 7-day post PEG and 14-day post PEG. Data are expressed as mean ± SD; statistical significance was determined by a two-sided Student’s t-test. PCoA: Principal coordinate analysis; PEG: Polyethylene glycol; OTU: Operational taxonomic unit; LEfSe: Linear discriminant analysis Effect Size.

Figure 5 Co-house for 7 days could eliminate the effect of polyethylene glycol. A: Mice were separately housed and co-housed for 7 days post polyethylene glycol (PEG) administration and prior to the infection of Citrobacter rodentium (CR); B: CR load in the feces; C and D: Representative hematoxylin and eosin staining (20 ×) and pathological score of the colon epithelium; E: Principal coordinate analysis of fecal microbiota among pre-PEG, 7-day post PEG of separately house and 7-day post PEG of co-house; F-H: Shannon, Chao, and ACE indices of operational taxonomic unit levels of fecal microbiota among 3 groups; I: Kruskal-Wallis H test for differences among 3 groups; J-M: Relative abundance of Lactobacillus, Akkermansia, Escherichia-Shigella and Alistipes on genus levels. Data are expressed as mean ± SD; statistical significance was determined by a two-sided Student’s t-test. CR: Citrobacter rodentium; PEG: Polyethylene glycol; CFUs: Colony-forming units; PCoA: Principal coordinate analysis; OTU: Operational taxonomic unit.

Figure 6 Supplementation of Lactobacillus acidophilus could decrease the effect of polyethylene glycol. A: Mice were gavaged with polyethylene glycol (PEG) and treated with phosphate buffered saline or Lactobacillus acidophilus (LAC) for 3 days prior to the infection of Citrobacter rodentium (CR); B: CR load in the feces; C and D: Representative hematoxylin and eosin staining (20 ×) and pathological score of the colon epithelium; E: Principal coordinate analysis of fecal microbiota among pre-PEG, 3-day post PEG and 3-day treatment of LAC; F: Shannon indices of operational taxonomic unit levels of fecal microbiota among pre-PEG, 3-day post PEG and 3-day treatment of LAC. Data are expressed as mean ± SD; statistical significance was determined by a two-sided Student’s t-test. CR: Citrobacter rodentium; PEG: Polyethylene glycol; CFUs: Colony-forming units; LAC: Lactobacillus acidophilus; PCoA: Principal coordinate analysis; OTU: Operational taxonomic unit.