Prevalence and Risk Factors for Methicillin-Resistant Staphylococcus aureus Colonization Among Outpatients Undergoing Hemodialysis Treatment

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) is frequent among hemodialysis patients and lead to increased morbidity and mortality rates. It is known that nasal colonization plays an important role for the development of MRSA infections. The aim of this study was to determine the prevalence and risk factors for MRSA colonization among outpatients undergoing hemodialysis. A total of 466 adult patients (199 female, 267 male; age range: 18-89 years, mean age: 55.8 +/- 15.1 years) who were under hemodialysis between September-December 2008 in different health centers at Pamukkale/Denizli region, Turkey, were included in the study. Swab samples obtained from anterior nares of patients were cultivated on sheep-blood agar and mannitol-salt agar media. The isolates were identified by conventional bacteriological methods. S.aureus strains were isolated from 204 (43.8%). patients and 34 (16.7%) were found methicillin-resistant. Thus the rate of MRSA colonization in hemodialysis patients was detected as 7.3% (34/466). All of the MRSA strains were found susceptible to vancomycin, linezolid and tigecycline, while the resistance rates for the other antimicrobial agents were as follows: 70.6% to azithromycin and claritromycin; 64.7% to erythromycin; %58.8 to clindamycin, gentamicin and trimethoprim-sulfamethoxazole; 55.9% to ciprofloxacin; 44.1% to tetracycline and rifampin; 5.9% to chloramphenicol. Inducible clindamycin resistance in MRSA isolates was %23.5 (8/34), and multidrug resistance rate was 76.5% (26/34). Multivariate analysis revealed that the history of previous hospitalization within a year [odds ratio (OR), 3.426; 95% confidence interval (Cl), 1.595-7.361, p=0.002] and the presence of chronic obstructive lung disease (OR, 5.181; 95% Cl, 1.612-16.648, p=0.006) were independent risk factors for MRSA colonization in this population. A better understanding of the prevalence and risk factors for nasal MRSA colonization among hemodialysis population may hold significant implications for both the treatment strategies and prevention of MRSA infections to establish appropriate infection control measures.