Clinical outcomes of penicillin skin testing

Background: Penicillin or cephalosporin allergy is a common problem with antibiotic drug prescribing in hospitalized patients. Objectives: To study the various clinical outcomes of penicillin skin testing (PST) in a community teaching hospital and to determine the percentage of patients who have an antibiotic drug modification after PST. Methods: This study was a retrospective medical record review of all inpatients who underwent PST in 6.6 years. Information was collected on 101 patients using a detailed data collection form. Data were summarized using descriptive statistics, including frequencies and percentages. Results: Of the 101 patients who underwent PST, 92 had a negative result and 5 had a positive result; in 4 patients the test result was indeterminate. There was a 96% (67/70) reduction in the use of vancomycin and a 96% (23/24) reduction in the use of fluoroquinolones after PST in patients with negative results. Forty-nine percent of patients with negative PST results were administered a penicillin-based drug, and 48% were given a cephalosporin. Cultures were positive most commonly for Staphylococcus oureus and enterococcus. There were no serious adverse reactions to PST or to the use of penicillins or cephalosporins after a negative PST result. Conclusions: Penicillin skin testing lowered the use of vancolnycin and fluoroquinolones and increased the use of penicillin-based drugs and cephalosporins in patients with a history of beta-lactaln drug allergies.