Clostridium difficile infection
Clostridium difficile infection (CDI) has become more refractory to standard therapy. Recent data showed severe refractory CDI successfully treated with tigecycline. Oral vancomycin is now advocated as the therapy of choice for severe CDI. Vancomycin administered intravenously does not reach therapeutic levels in the colonic lumen. Metronidazole, administered either orally or intravenously, only reaches low therapeutic levels in the colon. Therefore, even a slightly elevated minimal inhibitory concentration (MIC) of C. difficile for metronidazole may lead to therapy failure. Recently, C. difficile was reported to have low MIC values for tigecycline.
Because C. difficile colitis is a toxin-mediated disease, it has been assumed that immune globulin acts by binding and neutralizing toxin. Off-label use of pooled IVIG from healthy donors has been used in cases of severe refractory C. difficile infection and in patients with recurrent disease.