Defects of innate immunity are associated with which infections?

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Defects in innate immunity primarily impair the body's first line of defense against certain bacteria, especially where opsonization and neutrophil killing are key. The innate system, including neutrophils and the complement cascade, helps clear extracellular bacteria and encapsulated organisms. When this system is defective, you see susceptibility to pyogenic (pus-forming) bacteria and to Neisseria species. Neisseria infections ( meningitis, gonorrhea) are particularly linked to deficiencies in the complement pathway that affect bacterial clearance and membrane attack complex formation, while broader deficiencies in opsonization (like C3) lead to recurrent pyogenic infections by encapsulated bacteria.

Candida infections are more strongly associated with problems in cell-mediated immunity or with severe neutropenia in other contexts, and malaria is caused by a protozoan parasite, with its susceptibility pattern not classically tied to isolated innate immune defects.