Reduction in the Incidence of Methicillin‐Resistant Staphylococcus aureus and Ceftazidime‐Resistant Klebsiella pneumoniae Following Changes in a Hospital Antibiotic Formulary

Abstract

In 1995, changes in our hospital formulary were made to limit an outbreak of vancomycinresistant enterococci and resulted in decreased usage of cephalosporins, imipenem, clindamycin, and vancomycin and increased usage of β-lactam/β-lactamase-inhibitor antibiotics. In this report, the effect of this formulary change on other resistant pathogens is described. Following the formulary change, there was a reduction in the monthly number (mean ± SD) of patients with methicillinresistant Staphylococcus aureus (from 21.9 ± 8.1 to 17.2 ± 7.2 patients/1,000 discharges; P = .03) and ceftazidime-resistant Klebsiella pneumoniae (from 8.6 ± 4.3 to 5.7 ± 4.0 patients/1,000 discharges; P = .02). However, there was an increase in the number of patients with cultures positive for cefotaxime-resistant Acinetobacter species (from 2.4 ± 2.2 to 5.4 ± 4.0 patients/1,000 discharges; P = .02). Altering an antibiotic formulary may be a possible mechanism to contain the spread of selected resistant pathogens. However, close surveillance is needed to detect the emergence of other resistant pathogens.