Utilizing Pharmacy Records to Assess Antibiotic Prescribing Patterns on the Incidence of Community-Acquired...

To assess the effect of prior antibiotic therapy on the incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in children.

This was a concurrent and retrospective review of antibiotic records for children < 18 years of age with documented CA-MRSA infection identified between January 1, 2004, and December 31, 2005. Antibiotic records were compared against a control group. The primary outcome was the incidence of CA-MRSA using linear regression as a function of age and prior antibiotic therapy (i.e., 3 months prior to admission). Secondary objectives included a comparison of antibiotic courses and classes and a description of antibiotic susceptibilities in patients with CA-MRSA RESULTS: Data from 26 patients were included. Nine out of 51 patients (18%) with CA-MRSA were included. Another 17 children were enrolled in the control group. The median age was approximately 1.75 years (0.08-14 years) in the CA-MRSA group versus 2.75 years (0.005-15 years) in the control group. A statistical difference was noted in the number of patients with prior antibiotic exposure between the CA-MRSA and control group, 8 (88.9%) versus 6 (35.3%), respectively (P = .01). Antibiotic exposure was found to be a significant independent risk factor (P = .005; 95% CI, 0.167-0.846) for the development of CA-MRSA. The interaction between antibiotic exposure and age < 3 was the most significant predictor of CA-MRSA (P = .019; 95% CI, 0.139-1.40).

Prior antibiotic therapy in patients < 3 years of age was associated with a significant risk of developing CA-MRSA. A comprehensive assessment of CA-MRSA patients should include objective methods of measuring prior antibiotic exposure such as pharmacy records.