Is there a higher prevalence of methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) colonization in patients with antibiotic allergy labels?

Background A penicillin allergy label has been associated with significantly higher rates of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) colonization, and correspondingly poorer clinical outcomes. However, there are limited data examining the association between any antibiotic label and colonization rates. We sought to evaluate if there is a relationship between patients with an antibiotic allergy label and prevalence of MRSA or VRE colonization. Methods We retrospectively reviewed all patients with an MRSA surveillance culture between December 15, 2014 and January 31, 2015, or a VRE surveillance culture between January 1, 2013 and January 31, 2015, at a tertiary community-based teaching hospital. Our primary objective was to evaluate the prevalence of MRSA or VRE colonization among patients with and without antibiotic allergies. Bivariate analyses included the χ² test and the Student t test to determine statistical significance for categorical and continuous variables, respectively. Results We included a total of 1,053 unique patients screened for MRSA, and 290 unique patients screened for VRE. The rate of MRSA and VRE colonization was 5.8% (62 of 1,053) and 32.4% (94 of 290), respectively, in our cohort. Antibiotic allergies were documented in approximately 1 out of 3 patients, 337 (32%) for the MRSA group and 94 (32%) for VRE group. There was a significant difference in MRSA colonization between patients with and without an antibiotic allergy, 28 of 337 (8.3%) versus 34 of 716 (4.7%) (P = .025), respectively. In contrast, there was no significant difference in antibiotic allergy rates with and without VRE colonization, 34 of 94 (36.2%) versus 92 of 196 (46.9%) (P = .10), respectively. Conclusions An antibiotic allergy label was associated with significantly higher rates of MRSA colonization but no statistical difference with VRE colonization.