Nasal Carriage ofStaphylococcus aureusAmong Patients Receiving Allergen-Injection Immunotherapy: Associated Factors and Quantitative Nasal Cultures

Abstract

AbstractObjective:To compare the prevalence of nasalStaphylococcus aureuscarriage among outpatients receiving allergen-injection immunotherapy with the prevalence among healthy controls and to determine predictors of nasalS aureuscarriage.Design:Survey.Setting:Allergy clinic of a university hospital.Participants:A volunteer sample consisting of 45 outpatients undergoing desensitization therapy and 84 first- and second-year medical students.Results:The nasalS aureuscarriage rate was significantly higher among patients (46.7%) than among students (26.2%;P=.019). In a multivariate model adjusted for age and gender, the presence of atopic dermatitis or eczema was the only independent predictor of nasal Saureuscarriage (odds ratio [OR], 4.4; 95% confidence interval [CI95], 1.2-16.0;P=.02). The only other participant characteristic associated with nasalS aureuscarriage was immunotherapy with allergen injections (OR, 1.98; CI95, 0.7-6.0), but this association did not reach statistical significance (P=.23). The probability of nasalS aureuscarriage was 88.9% for patients receiving allergen injections and having atopic dermatitis or eczema, and 36.1% for patients receiving allergen injections without atopic dermatitis or eczema.Conclusions:Patients undergoing desensitization have a higher nasal carriage rate ofS aureus.However, factors other than the regular use of needles, and in particular abnormalities related to the atopic constitution of these patients, may predispose this population forS aureuscarriage.