As the child had recurrent infections caused by catalase-positive organisms (S. aureus in the family of Staphylococcaceae, and B. cepacia in the Burkholderiaceae-rRNA group II of B. cepacia complex) requiring multiple courses of IV antibiotics, Candida infection, evidence of deep-seated abscess during the past 1 year, the possibility of IEI (Jeffery Modell Foundation criteria: (1) requiring IV antibiotics to clear the infection, (2) two deep-seated infections - subcutaneous abscess and septicemia, and (3) vaginal candidiasis beyond 1 year of age) was considered. This evidence concerns the gene CAT and infection.