The impact of nasal carriage of methicillin-resistant and methicillin-susceptible Staphylococcus a ureus (MRSA & MSSA) on vascular access-related septicemia among patients with type-II diabetes on dialysis.

BACKGROUND: Fairly higher nasal carriage rates among type-II diabetics place them at a greater risk of endogenous Staphylococcus aureus linked vascular access-related septicemia (VRS) that is also dependent on the type of vascular access used for hemodialysis (HD). The prevalence of nasal carriage of methicillin susceptible and methicillin-resistant S. aureus (MSSA and MRSA) and its impact on VRS was determined in order to identify most vulnerable group and plan potential prophylactic strategies, accordingly.

METHODS: Five standardized nasal swab cultures were performed in 208 patients enrolled for long-term HD through July 1996 to July 1999. Persistent nasal carriage was defined by two or more positive cultures for MSSA or MRSA. Peripheral blood cultures were collected on clinical suspicion of septicemia.

RESULTS: The prevalence of type-II diabetes of 28.0% with 72.4% of nasal carriage rate and three folds higher S. aureus related VRS (RR-3.19, p<0.0001) than diabetic non-carriers on HD, was observed. Type-II diabetics also had higher MSSA and MRSA nasal carriage rates (53.4% and 19.0%) than non-diabetic nasal carriers (18.6 and 6.0%) yet, carried a comparable (RR-4.0 vs. 4.5) risk of VRS between MSSA and MRSA nasal carriers. Among diabetic type-II S. aureus nasal carriers, central venous catheters (CVCs) carried 35 and 38 times higher collective risk of developing MSSA and MRSA nasal carriage-related VRS respectively than Arterio-venous fistula (AVF). The AVF recorded the lowest risk of developing MSSA and MRSA nasal carriage-related VRS (0.013 and 0.010 episodes/patient-year) in both diabetic type-II MSSA and MRSA nasal carrier groups.

CONCLUSIONS: Diabetic type-II S. aureus nasal carriers on HD through CVCs make an extremely high-risk group for MSSA and MRSA nasal carriage-related VRS. The incidence of S. aureus nasal carriage-related VRS could reasonably be reduced through a challenging obligation of optimizing AVF prevalence in this high-risk group, while limiting the use of CVCs, at the same time.