The Clostridium difficile spo0A Gene Is a Persistence and Transmission Factor

C. difficile spo0A mutants produce elevated levels of TcdA and TcdB and exhibit increased virulence in mice. (A) Kaplan-Meier survival curve of mice infected with C. difficile 630, R20291, 630Δspo0A, or R20291Δspo0A. (B) Representative images demonstrating epithelial cell damage in hematoxylin- and eosin-stained cecal sections of mice infected with C. difficile R20291 or R20291Δspo0A. Magnification, ×20. (C) Sandwich ELISA indicating the relative levels of TcdA and TcdB produced by C. difficile R20291 or R20291Δspo0A after 30 h of growth in Wilson's broth under anaerobic conditions. Data are from 3 independent experiments performed in triplicate. The error bars indicate standard deviations.

C. difficile spo0A mediates intestinal persistence in mice. Shown are the CI time courses of C. difficile R20291 and R20291Δspo0A (A) and 630 and 630Δspo0A (B). Individual CI values are illustrated as open circles, and the horizontal bars represent the geometric means. The second through fourth (A) and third and fourth (B) spo0A mutants are attenuated, as determined by the Mann-Whitney test.

The C. difficile spo0A gene is required for relapsing disease in mice. (A and B) Representative fecal shedding profiles from mice (n = 5 per group) infected with C. difficile 630, R20291, 630Δspo0A, or R20291Δspo0A. The mice were pretreated with clindamycin (clin) (represented as a gray line) for 7 days prior to infection via oral gavage. Following infection, the mice received a series of 7- to 10-day courses of vancomycin (van) (represented as green lines) during which fecal shedding of C. difficile decreased to below the detection limit of the assay in all groups of mice. The dashed horizontal lines indicate the detection limit.