Is C. diff (Clostridium difficile) contagious? Yes, C. diff is contagious. Microorganisms can be spread from person-to-person by touch or by direct contact with contaminated objects and surfaces (for example, clothing, cell phones, door handles). Some individuals are carriers of this bacterium but have no symptoms of infection. However, these people are still infected with the bacteria can spread the infection to others. In general, the bacteria have to increase in numbers rapidly to cause disease, so the bacteria can be transferred to people, but not cause significant infection immediately. Disease occurs when conditions favor growth of these organisms. Conditions that favor growth are weakened immune systems, the elderly, and especially individuals that are hospitalized, and are being treated with antibiotics that suppress the normal bowel flora. Avoiding direct and indirect physical contact with contaminated areas reduces the likelihood of contagions.