Hello, My answers are as follows: In most cases animals and pets (dogs and cats) serve as carriers or vectors of C. difficile to humans. Dogs get the bacteria through close contact with infected individuals, but they just eliminate it and usually pets do not get sick, even though in some cases C. difficile could be the cause of fatal diarrhea in dogs. C. difficile eliminated by dogs and excreted in environment could infect again humans and in these cases the bacteria strains are highly resistant to metronidazole, clindamicin and other macrolides used mostly to treat C.difficile infection in humans. Therefore, pets are rather safe from the infection but they are also to be screened because that could serve as reservoirs of the bacteria and source of infection to humans. With regard to your second question, I guess that you have already used metronidazole and vancomycin. Literature suggests that recurrence of disease is found in about 25% of cases. The use of Fidaxomicin, a macrolide class antibiotic, could be helpful in these cases as it is associated with lower relapse rate. Also, high doses of Vancomycin (500mg every 6 hours) IV or per rectumcould be helpful for resistant cases. Sometimes, the so-called fecal transplantation could be used to treat peudomembranous colitis. However, these options should be discussed with your specialist doctor in order to decide the best treatment regime for you. To prevent the infection meticulous hygienic and disinfection measures have to be taken, in close consultation with your doctor as well. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Ervin Toçi