Staphylococcus aureus nasal carriage in patients on haemodialysis:: role of cutaneous colonization

We performed a prospective study of Staphylococcus aureus nasal carriage in patients on chronic haemodialysis to determine the role of cutaneous colonization in the aetiology of recurrent nasal colonization. From February 2000 to September 2001, 71 patients on chronic haemodialysis in the dialysis unit at a university hospital were screened monthly for S. aureus nasal. carriage. Carriers received nasal mupirocin for five days and were tested for nasal, and cutaneous carriage two days later and monthly thereafter. Using genotyping results, recurrence was defined as relapse if pretreatment and subsequent nasal isolates were clonally identical; if the isolates were different, it was considered recolonization. Thirty-nine patients (55%) were nasal carriers: 11 initiatly and 28 during follow-up. Among the mupirocin-treated patients, the eradication of S. aureus nasal carriage rate was 88.5%. Nasal recurrence was documented in 17 patients (43.5%), and S. aureus nasal strains were available for molecular typing in 14 patients with a total of 23 recurrence episodes. On the basis of pulsed-field get electrophoresis analysis, 16 (70%) recurrence episodes were considered relapses and seven were considered (30%) recolonizations. Among the episodes of relapse, prior cutaneous colonization was detected in only three cases. In haemodialysis patients, the majority of nasal carriage recurrences after mupirocin therapy were due to relapses. Cutaneous colonization does not appear to be relevant in the development of these relapses. (C) 2004 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.