Serratia marcescens osteomyelitis in an infant

Neutrophil dysfunction can result from oxidative burst defect or from glucose-6-phosphate dehydrogenase (G6PD) deficiency; we noted both in the same patient. A 4-month-old male infant with G6PD deficiency presented with swelling of the left middle finger, left leg, and right big toe. At 5 weeks of age he was hospitalized for fever for 2 days. A maternal uncle died at 5 years of age and a male maternal cousin died at the age of 21 months, both reportedly diagnosed with chronic granulomatous disease (CGD). On physical examination, he had a swollen erythematous left third finger, left distal leg swelling, and right big toe abscess. None of these areas was significantly tender. WBC was 18.7 x 10(3)/mm(3) with 37% PMN and 5% bands. The x-ray films showed osteomyelitis in the left third proximal phalanx and the distal right first metatarsal. Culture from the toe abscess grew Serratia marcescens. His neutrophil oxidative burst was tested by the dihydrorhodamine-123 assay and was markedly suppressed, typical of CGD. The mother and maternal grandmother were found to be CGD carriers. He was treated with i.v. antibiotics for 4 weeks and was discharged on prophylactic trimethoprim, itraconazole and interferon gamma, with substantial reduction in infections. Infection in this infant was unusual in its nature, in affecting multiple sites, and in its causative organism. Immune deficiency was suspected, particularly of the phagocytic component, but could not be attributed to his moderate degree of primary G6PD deficiency. Additional immunologic evaluation and the family history led to the diagnosis of X-linked CGD.