Fig 4.

Successful colonization of the murine gastrointestinal tract by V. parahaemolyticus RIMD2210633 requires antibiotic pretreatment. (A) C57BL/6 mice were orally dosed with PBS (open squares) or streptomycin (Str; 20 mg/animal; filled squares) 1 day prior to oral infection with V. parahaemolyticus. At 48 h postinfection, the entire gastrointestinal tracts (small intestine to the descending colon) were isolated from infected animals. The entire gastrointestinal tracts then were homogenized in PBS and plated on LB agar containing 3% NaCl and 200 μg/ml streptomycin. (B) Tissues of the GI tract were also separated into the small intestine (filled squares), cecum (filled circles), and large intestine (filled diamonds), gently flushed of fecal content, and homogenized in PBS. Samples were serially diluted and plated on LB agar containing 3% NaCl and 200 μg/ml streptomycin to determine the numbers of tissue-associated V. parahaemolyticus cells. Data are pooled results from two separate experiments (n = 10 for each treatment). In both panels the solid line indicates the means and the dashed line indicates the limit of detection. P values were calculated using an unpaired Student's t test with a 95% confidence interval. Asterisks denote significant differences between groups for data under the bracket. **, P < 0.01; ***, P < 0.0001. Si, small intestine; Ce, cecum; Li, large intestine.