Nasal and extra-nasal methicillin resistant Staphylococcus aureus colonization among hemodialysis patients; is routine culturing of other body sites necessary?

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Introduction: Asymptomatic Staphylococcus aureus carriers have become a great concern because of being at risk of subsequent S. aureus infections. The role of nasal S. aureus carriages as an endogenous source for staphylococcal infections especially methicillin resistant S. aureus (MRSA) infections has been known that seems to be contributed to morbidity, mortality, and also the cost of end-stage renal disease management. Besides, many recent studies have demonstrated that extranasal sites may be important unrecognized reservoirs for resistant S. aureus. Objectives: The purpose of the present research was to identify the frequency and factors associated with extra-nasal S. aureus colonization among maintenance hemodialysis patients. Patients and Methods: A total of 179 hemodialysis patients were enrolled in this study. Swab cultures were obtained from anterior nares, posterior pharynx, and the inguinal area. Culture plates were analyzed for the presence of methicillin-resistant or methicillin-susceptible S. aureus using standard microbiological techniques for S. aureus and MRSA. Results: 113 out of 179 patients (63%) were men and 66 (37%) were women with the mean age of 59.8±13.6 years. 36 out of 179 patients (20%) were colonized with S. aureus which 5 patients (2.7%) were colonized with MRSA. Prevalence of extra-nasal S. aureus colonization was 12% ( 22/179 patients), the prevalence of nasal S. aureus colonization was 10% (18/179 patients) and 2.7% of patients (5/179 patients) were colonized with S. aureus in more than one body site. Around 3 out of 5 MRSA colonized patients (60%) were extra-nasal carriers. There was a significant association between type of venous access for dialysis with the extra- nasal colonization (P=0.03) and also an association between underlying disease of diabetes mellitus type 2 with the extra-nasal colonization (P=0.01). Conclusion: This study has emphasized the importance of extra-nasal evaluation along with nasal site sampling as an endogenous risk factor for staphylococcal infections among hemodialysis patients.