Identify methicillin-resistant Staphylococcus aureus nasal carriers in hemodialysis patients

Abstract

Wang et al 1 reported in the Journal of the Formosan Medical Association the prevalence rate of methicillinresistant Staphylococcus aureus (MRSA) nasal colonization in hemodialysis (HD) patients in Taiwan was 5.9%, which was nearly one-half of those reported by Lederer et al. 2 from Germany. However, the methods of detecting MRSA carriage were different in these two studies: the former used one single nasal swab culture, while the later used at least two (varied between two and 10) nasal swab screenings. It is inappropriate to compare a prevalence rate by using different detecting strategies. Our previous report detected MRSA carriers by performing two consecutive nasal swab cultures obtained at a 1-week interval in another tertiary medical center in northern Taiwan. 3 Those who had at least one positive culture of MRSA were defined as MRSA carriers. We found the prevalence of MRSA nasal carriage in HD patients was 9.48%. In detail, there were 13 (4.25%) persistent carriers and 16 (5.23%) intermittent carriers. Following this paper, serial annual surveillance of MRSA nasal carriage in our HD patients still identified these two patterns of MRSA carriers (Table 1). Using only one examination may fail to identify a significant portion of MRSA carriers. Similar findings were also shown in other studies to detect S. aureus carriership. 4,5 Therefore, we suggest screening of MRSA nasal carriage in HD patients should be carried out by at least two consecutive weekly nasal swab cultures in order to maximize the probability of identifying all MRSA carriers.