Changing patterns of bacterial resistance in relation to prophylactic use of cephaloridine and therapeutic use of ampicillin.

Antibiotic sensitivities of 15302 organisms of common pathogenic species isolated in one hospital pathology department in 1971 and 1974 have been studied. Resistance to cephaloridine did not change materially. The proportion of strains resistant to ampicillin did, however, increase, and this is attributed to the widespread therapeutic use of the antibiotic. Cephaloridine, on the other hand, was largely used in the hospital as a single-dose, intra-incisional prophylactic against surgical wound sepsis.