Neisseria lactamica septicemia in an immunocompromised patient.

Neisseria lactamica was isolated from the blood of a 7-year-old girl who was immunosuppressed from chemotherapy for acute lymphocytic leukemia. She was receiving trimethoprim-sulfamethoxazole prophylactically. The isolate was resistant to trimethoprim-sulfamethoxazole and sensitive to penicillin. The patient responded to intravenous penicillin therapy. The organism did not produce immunoglobulin A1 protease.