Elimination of Staphylococcus aureus nasal carriage in intensive care patients lowers infection rates
This study surveys the clinical relevance of the nasal Staphylococcus aureus colonization status on intensive care unit (ICU)–acquired S. aureus infections and compares molecular characteristics of isolates from the nose and infectious sites. The 390 patients included comprised 278 non-carriers and 112 carriers. Among the carriers, 56 were decolonized with mupirocin. Decolonization was verified through a second (negative) culture. Spa typing and virulence gene profiling were performed for all isolates. Twenty six S. aureus infections were detected in the carriage group and 20 in the non-carriage group. Eighteen of these 26 (69.2%) infections were among carriers, and 8 of these 26 (30.8%) infections occurred among decolonized carriers (p = 0.02). Overall, 31/112 (27.7%) of the colonized patients and 25/46 (60.1%) of infection were due to methicillin-resistant S. aureus (MRSA). The highest frequency virulence genes were sea and hlg (both 100%) in nasal isolates and sea, hlg, fnb, and clf (100%) for infectious isolates. t030 was the most abundant spa type overall. S. aureus carriers were more likely to develop S. aureus infection compared with decolonized and non-carrying patients. The sources of ICU S. aureus infection appear to be exogenous mostly, and a predominant clone (spa type 030) plays an important role. We confirm that nasal mupirocin treatment prevents ICU infections even when there is an increased prevalence of nosocomial MRSA.
KeywordsStaphylococcus aureus Nasal carriage Nosocomial infections Intensive care unit
This work was financially supported by the Arak University of Medical Sciences, Iran, for which we are thankful. This paper is extracted from a dissertation by Leila Akhtar Danesh to fulfill the requirement for Master of Sciences in Medical Bacteriology and Zeinab Saiedi Nejad to become a specialist in infectious diseases.
EGR, AVB, and HS conceptualized, designed, and supervised the study. LA and SF were involved in the sample collection and performed laboratory experiments. ZS managed the decolonization of patients and all other activities in the ICUs. All the authors contributed in writing and editing of the draft and have seen and agreed to the submitted version of the paper.
Compliance with ethical standards
Conflict of interest
AVB is an employee of BioMérieux, a company designing, developing, and selling infectious disease tests. The authors report no other conflicts of interest.
The company had no influence on the design and execution of the study or in the writing of the manuscript.
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