In chronic granulomatous disease, which of the following pathogens is commonly involved?

Chronic granulomatous disease (CGD) is a genetic disorder characterized by the inability of phagocytes to effectively kill certain types of bacteria and fungi due to a defect in the NADPH oxidase enzyme complex. This defect leads to impaired production of reactive oxygen species (ROS), which are crucial for the oxidative burst required to destroy ingested pathogens.

Individuals with CGD have a heightened susceptibility to catalase-positive organisms because these pathogens can neutralize the hydrogen peroxide that could otherwise be used in the immune response. Staphylococcus aureus is a catalase-positive bacterium that is commonly involved in infections in patients with CGD. Other catalase-positive organisms that may cause issues in CGD patients include Aspergillus species and other fungi.

The other pathogens listed are either catalase-negative or less commonly associated with infections in the context of CGD. For example, Escherichia coli is catalase-positive but primarily associated with infections in those with normal immune function rather than CGD, while Streptococcus pneumoniae is generally treated effectively by the innate immune system, and Clostridium difficile does not typically pose a significant risk to patients with CGD compared to catalase-positive organisms. Therefore, the correct answer highlights the typical infections seen