PMC4410979_01
Platelet counts and piperacillin administration in the patient presented in this report. The bars at the top represent administration of piperacillin on Days 1-3, 6-10, and 19-21.
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F1
On Day 11, his platelet count decreased to 70,000/microL from 201,000/microL the previous day (Fig. 1). On Day 13, the platelet count began to recover after reaching a nadir of 33,000/microL, becoming normal on Day 16 (Fig. 1). The patient's platelet count recovered to normal 3 days after piperacillin/tazobactam was stopped (Fig. 1).
Demonstration of a piperacillin-dependent, platelet-reactive antibody in the patient presented in this report (left) and absence of a detectable tazobactam-dependent, platelet-reactive antibody (right). Results shown are representative of three independent studies that gave essentially identical results. Platelet median fluorescence intensity (MFI values shown) obtained with our patient's serum plus piperacillin (9.0) differed significantly from those obtained with our patient' serum plus buffer (4.4) and with normal serum plus piperacillin (4.4) (P < 0.01, Student's t-test). The much stronger drug-dependent reaction of serum from a patient with quinine-induced thrombocytopenia plus quinine (65) is also shown.
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F2
Piperacillin as the etiology of the thrombocytopenia in our patient was confirmed by documentation of piperacillin-dependent platelet-reactive antibodies and by the absence of tazobactam-dependent platelet-reactive antibodies (Fig. 2).