Chapter 23 : Gastrointestinal Infections

Abstract:

Gastrointestinal (GI) infections in the immunocompromised host include the common bacterial, viral, fungal, and parasitic agents that also cause infections in the immunocompetent host ( Table 1 ). Of special consideration is that immunocompromised patients may be at increased risk for, or experience, increased disease length and severity caused by many common GI pathogens. As the stomach is a major barrier to colonization by some enteric pathogens, it is not surprising that there may be changes in gastric microbiota in the immune-compromised patient that could be involved in increasing the risk of infection ( 1 ). Patients with human immunodeficiency virus (HIV) infection, recipients of solid-organ and bone-marrow transplant, patients with hematologic or other malignancies, or with diabetes, or patients receiving immunosuppressive chemotherapy and corticosteroid therapy, as well as patients with poor nutritional status, and/or at the extremes of age, are all at risk for conventional and opportunistic infections of the GI tract. Patients with primary immunodeficiencies may have GI lesions that are similar to other noninfectious diseases ( 2 ). Additionally, certain microorganisms cause infection in the compromised host but rarely, if ever, are observed in the normal, immunocompetent population ( Fig. 1 ). Some infections that may indicate an underlying immunodeficiency include Candida spp. esophagitis or microsporidial enteritis, which may be the first acquired immunodeficiency syndrome (AIDS)-defining illness experienced by patients with HIV infection.