Q: What is the risk of acid suppression medication in developing C. Diff. Colitis? 

Answer: 

Acid suppression medications increases the risk of C. Diff. Colitis.

H2-receptor antagonists increased the risk 1.5-fold,

and

Proton pump inhibitors by 1.7 with once-daily use and 2.4 with more than once-daily use

Reference: 

1. Howell, MD; Novack, V; Grgurich, P; Soulliard, D; Novack, L; Pencina, M; Talmor, D (May 2010). "Iatrogenic gastric acid suppression and the risk of nosocomial Clostridium difficile infection". Archives of Internal Medicine 170 (9): 784–90.

2. Deshpande, A; Pant, C; Pasupuleti, V; Rolston, DD; Jain, A; Deshpande, N; Thota, P; Sferra, TJ et al. (March 2012). "Association between proton pump inhibitor therapy and Clostridium difficile infection in a meta-analysis". Clinical Gastroenterology and Hepatology 10 (3): 225–33.