A NEW CONCEPT IN THE TREATMENT OF PENI- CILLIN REACTIONS: USE OF PENICILLINASE * t

A PREVIOUS report * described the in vivo action of penicillinase on cir-culating penicillin in guinea pigs and human subjects without reactions. The following is a report of the clinical effectiveness of penicillinase in hu-mans with penicillin reactions. Penicillinase 2 is an enzyme specific for its substrate penicillin. Its in-activating action against penicillin has been utilized for years in the clinical laboratory in bacteriologic media to inhibit penicillin in body fluids to be cultured. Penicillinase can be obtained from several strains of bacteria, in-cluding staphylococci and Escherichia coli. Commercially it is produced in greatest abundance from cultures of Bacillus cereus, strain NRRL-B 569 (Schenley Laboratories). The precipitation and purification of the enzyme are described in the initial report.1 The inactivating action of penicillinase is through its catalytic hydrolysis of the lactam ring of the penicillin molecule, changing penicillin to penicilloic acid,2 '3 which is nonantigenic in this sensitivity system.1 In the original study it was found that in guinea pigs and humans with-out reactions who had received penicillin, and in whom consistent penicillin blood levels were established, no circulating penicillin could be found within * Received for publication May 17, 1957. t The penicillinase used in these studies was generously supplied by Schenley Labora