Nasal carriage of Staphylococcus aureus in families of children on peritoneal dialysis. European Pediatric Peritoneal Dialysis Study Group (EPPS).

Nasal carriage of Staphylococcus aureus is a risk factor for catheter-related infections with S. aureus in patients on chronic peritoneal dialysis (CPD). In children, S. aureus may transmitted to the catheter either from the patients' nares, or from the nares of caregiving carriers. As part of a prospective trial on the efficacy of mupirocin prophylaxis in children on CPD and their caregivers, we evaluated the prevalence of S. aureus carriage in 92 families of pediatric CPD patients. Patients and their caregivers (usually both parents) were screened by three nasal cultures obtained within four weeks. In 62% of the families, neither the patients nor any caregiver carried S. aureus. In 23%, the patient or at least one caregiver (sometimes both) was identified as a carrier. In 15%, at least one caregiver, but not the patient, was colonized with S. aureus. During further follow-up by once-monthly nasal cultures, 5 of the 57 initially negative patients developed S. aureus colonization, and in two families, at least one caregiver turned positive. Including these "occasional" carriers, the cumulative likelihood of one or several family members carrying S. aureus gradually increased to a plateau of about 55% after 6 observation months. Susceptibility rates of cultured S. aureus were 100% for vancomycin, 99% for aminoglycosides, 95% for piperacillin/tazobactam, 94% for cephalosporins, and 15% for ampicillin. In two patients and two caregivers (four different families), methicillin-resistant S. aureus was found. Three isolates from three different families were resistant to mupirocin. We conclude that S. aureus colonization is common in families of children on CPD. While 85% of carrier families are detected by 3 sequential nose cultures in patient and caregivers, up to 9 cultures may be required in "occasional" carriers.