NATURAL-HISTORY OF STAPHYLOCOCCUS-AUREUS NASAL CARRIAGE AND ITS RELATIONSHIP TO EXIT-SITE INFECTION

Objective:To study the natural history of nasal carriage of Staphyloco ccus aureus (SA) and its impact on exit-site infection (ESI). Setting: A teaching hospital single-center study. Design: A prospective cohort study in prevalent continuous ambulatory peritoneal dialysis (CAPD) p atients. Patients: 153 patients (76 male, 77 female; mean age 46 years ) with a mean duration of CAPD of 2.4 years. Methods: Nasal swabs were taken at approximately 2-month intervals over the mean period of foll ow-up of 22.6 months and cultured for SA. Results: An average of 69% o f patients received systemic antibiotics for therapy of ESI, peritonit is, and other infections during the period of the study, but none rece ived local nasal antibiotics. Four groups of patients were identified according to their nasal carriage history: chronic, intermittent, occa sional, and noncarriers.The intermittent and chronic carriers had sign ificantly higher SA ESI than the occasional and noncarrier groups. The intermittent group also had the highest percentage of non-SA ES infec tions. Conclusion: Although this study shows that only half of our CAP D patients with nasal carriage were at risk of developing ESI, we reco mmend that patients with a positive nasal swab;at the start of CAPD th erapy should be treated with nasal antibiotics or local antibiotics at the exit site.