Extranasal S aureus colonization predisposes to bloodstream infections in patients on hemodialysis with non-cuffed internal jugular vein catheters

Background: Staphylococcal infection of endogenous origin is an important cause of morbidity and mortality in patients who receive hemodialysis (HD). The risk of such infections in nasal carriers of the organism is well defined. Extranasal carriage of the organism at extranasalsites may pose similar risks. Design: Prospective observational study. Setting and Participants: A total of seventy patients about to undergo internal jugular vein catheterization for HD were enrolled. Swab cultures were obtained from anterior nares, posterior pharynx, axillae, toe toe web spaces and vascular access sites at baseline and one week later. A patient was defined as a persistent carrier when the same organism was grown in both samples. Outcomes: S. aureusbloodstream infections as assessed by blood and catheter tip cultures over a 90 day period. Measurement: Number of catheter related bloodstream infections amongst different subgroups using parameteric and non-parameteric tests. Results: The mean age of the patients was 43.71±16.2 years. Persistent S. aureus carriage at anterior nares, throat, axilla, toe web spaces, vascular access site and all sites was documented in 27.9%, 11.4%,40%,32.9%,4.3% and 64.2% of patients respectively. Fifteen patients developed S. aureus related infections. Catheter related S. aureus infections (CRI) were more likely in persistent carriers than non persistent carriers with odds ratios (95% CI) of 10.2 (2.8-37.1), 8.6 (1.7-42.2), 17.3 (3.4-86.0), 3.0 (0.9-9.8) and 1.9 (0.2-22.4) foranterior nares, throat, axilla, toe web spaces andvascular access site carriers respectively. The probability of developing CRI in persistent S. aureus carriers was 55% compared to none in non carriers at 90 days (p=0.04). Limitations: Small number of subjects, lack of molecular phenotyping. Conclusion: ExtranasalS aureuscarriage is as significant a risk factor as nasal carriage for staphylococcal infections in patients on HD through catheters.