Ticarcillin-induced neutropenia corroborated by in vitro CFU-C toxicity.

A patient developed a drug rash and neutropenia while receiving tobramycin, ticarcillin and flucloxacillin intravenously for osteomyelitis. Incorporation of these antibiotics into in vitro cultures of bone marrow granulocyte macrophage precursors (CFU-C) showed no inhibition of the patient's marrow or normal marrow by tobramycin. The patient's marrow was more sensitive to ticarcillin than were control cultures, and all cultures incorporating flucloxacillin failed to show growth of CFU-C. Drugs of the penicillin group appear to be responsible for the patient's neutropenia.