Persistent nasal methicillin-resistant staphylococcus aureus carriage in hemodialysis outpatients: a predictor of worse outcome

Background: Nasal colonization with methicillin-resistant
Staphylococcus aureus (MRSA) is a well defined risk factor for
subsequent bacteremia and death in various groups of patients, but
its impact on outcome in patients receiving long-term hemodialysis
(HD) is under debate. Methods: This prospective interventional
cohort study (performed 2004 to 2010) enrolled 289 HD outpatients
of an urban dialysis-unit. Nasal swab cultures for MRSA were
performed in all patients upon first admission, at transfer from
another dialysis facility or readmission after hospitalisation.
Nasal MRSA carriers were treated in a separate ward and received
mupirocin nasal ointment. Concomitant extra-nasal MRSA colonization
was treated with 0.2% chlorhexidine mouth rinse (throat) or
octenidine dihydrochloride containing antiseptic soaps and 2%
chlorhexidine body washes (skin). Clinical data and outcome of
carriers and noncarriers were systematically analyzed. Results: The
screening approach identified 34 nasal MRSA carriers (11.7%).
Extra-nasal MRSA colonization was observed in 11/34 (32%) nasal
MRSA carriers. History of malignancy and an increased Charlson
Comorbidity Index were significant predictors for nasal MRSA
carriers, whereas traditional risk factors for MRSA colonization or
markers of inflammation or malnutrition were not able to
discriminate. Kaplan-Meier analysis demonstrated significant
survival differences between MRSA carriers and noncarriers.
Mupirocin ointment persistently eliminated nasal MRSA colonization
in 26/34 (73.5%) patients. Persistent nasal MRSA carriers with
failure of this eradication approach had an extremely poor
prognosis with an all-cause mortality rate >85%. Conclusions:
Nasal MRSA carriage with failure of mupirocin decolonization was
associated with increased mortality despite a lack of overt
clinical signs of infection. Further studies are needed to
demonstrate whether nasal MRSA colonization represents a novel
predictor of worse outcome or just another surrogate marker of the
burden of comorbid diseases leading to fatal outcome in HD
patients.