Isolated polypeptide of the toxin A and toxin B proteins of

1. A method for the prevention and/or treatment of a C. difficile associated disease (CDAD) comprising administering to a subject:

a) an isolated polypeptide, or

b) a pharmaceutical composition or immunogenic vaccine comprising the isolated polypeptide,

wherein the polypeptide comprises an amino acid sequence having at least 85% sequence identity to the amino acid sequence as set forth in SEQ ID NO: 4 and comprises 23 repeating units derived from the C-terminal domain of toxin B of C. difficile , wherein the sequence identity is determined by Needleman-Wunsch global alignment.

2. The method of claim 1 , wherein the subject is:

i) an elderly subject or a subject below 2 years of age;

ii) a subject with AIDS;

iii) a subject taking or planning to take immunosuppressing drugs;

iv) a subject with planned hospitalization or a subject that is in hospital;

v) a subject in or expected to go to an intensive care unit;

vi) a subject that is undergoing or is planning to undergo gastrointestinal surgery;

vii) a subject that is in or planning to go to a long-term care such as a nursing home;

viii) a subject with comorbidities requiring frequent and/or prolonged antibiotic use;

and/or

ix) a subject with recurrent CDAD.

3. The method of claim 1 , wherein said polypeptide comprises an amino acid sequence having has at least 90% sequence identity to the amino acid sequence as set forth in SEQ ID NO: 4.

4. The method of claim 1 , wherein said polypeptide comprises an amino acid sequence having has at least 95% sequence identity to the amino acid sequence as set forth in SEQ ID NO: 4.

5. The method of claim 1 , wherein said polypeptide comprises an amino acid sequence having has at least 99% sequence identity to the amino acid sequence as set forth in SEQ ID NO: 4.

6. The method of claim 1 , wherein said polypeptide consists of the amino acid sequence as set forth in SEQ ID NO: 4.

7. The method of claim 1 , wherein said polypeptide comprises 19 repeating units derived from the C-terminal domain of toxin A of Clostridium difficile.

8. The method of claim 1 , wherein the polypeptide elicits antibody binding to native C. difficile toxin A and/or B and neutralizes cytotoxic activity of C. difficile toxin A and/or B.

9. The method of claim 1 , wherein the polypeptide promotes survival of a hamster vaccinated with said polypeptide after intragastric administration of a lethal dose of C. difficile spores at spore doses of 10 2 , 10 3 and 10 4 .

10. The method of claim 1 , wherein the pharmaceutical composition or vaccine composition comprising the polypeptide further comprises an adjuvant.

11. The method of claim 10 , wherein said adjuvant comprises alum.

12. The method of claim 1 , wherein the pharmaceutical composition or vaccine composition comprising the polypeptide further comprises an additional agent.

13. The method of claim 1 , wherein pharmaceutical composition or vaccine composition further comprises a therapeutic agent selected from the group consisting of anesthetics, analgesics, anti-inflammatories, steroids, antibiotics, antiarthritics, anorectics, antihistamines and antineoplastics.

14. The method of claim 1 , wherein the administration is intramuscular.

15. The method of claim 1 , wherein the subject had a C. difficile infection and is at risk for re-infection with C. difficile or the subject is currently infected with C. difficile.

16. The method of claim 1 , wherein the subject is a human subject.

17. The method of claim 1 , wherein the administration comprises one dose of the polypeptide, or the pharmaceutical composition or immunogenic vaccine comprising the polypeptide.

18. The method of claim 1 , wherein the administration comprises two or more doses of the polypeptide, or the pharmaceutical composition or immunogenic vaccine comprising the polypeptide.