C. difficile
noun [ U ] medical specialized uk/ˌsiː dɪˈfɪs.ɪ.liː/ us/ˌsiː dɪˈfɪs.ɪ.liː/ (also C. diff, uk/ˌsiːˈdɪf/ us)
艰难梭菌（一种细菌，极小的生物，能导致难以治愈的重病，Clostridium difficile的缩写）
abbreviation for Clostridium difficile: a type of bacterium (= an extremely small organism) that can cause serious illness and that is very difficult to treat
The elderly are at increased risk from C. diff. 老人更容易感染艰难梭菌。