Colonization With Methicillin-Resistant Staphylococcus aureus Upon Intensive Care Unit Admission: Incidence and Risk Factors

Since earlier identification of methicillin-resistant Staphylococcus aureus (MRSA)-colonized patients could be helpful for reducing the overall frequency of S. aureus infections, the investigation of persons colonized with MRSA is considered to be a key component of MRSA infection prevention programs, particularly among ICU patients.
The aim of the present study was to evaluate the prevalence of nasal and extra-nasal carriers of MRSA and risk factors associated with MRSA colonization among adult patients admitted to the ICU.
In a cross-sectional study, 164 adult patients who were admitted to the ICU of a teaching hospital were screened for nasal and extra-nasal carriage of MRSA. In addition, the ICU-hospitalized patients were evaluated for MRSA acquisition during their ICU stay.
Out of the 164 patients admitted to the ICU, 12 (7.3%) patients were methicillin-susceptible Staphylococcus aureus (MSSA) carriers, and 12 (7.3%) patients carried MRSA. Four (16.6%) patients were colonized at single or multiple extra-nasal sites based on negative nares screening. Of the 15 remaining patients hospitalized at the ICU, one (6.7%) patient acquired MRSA. The patients colonized with MRSA had more advanced ages (P = 0.008), longer hospital stays before being transferred to the ICU (P > 0.001), more underlying diseases with chronic obstructive pulmonary disease (COPD) (P = 0.028), and had undergone surgery (P = 0.003). Patients transferred from the surgical wards to the ICU were found to have significantly higher carriage rates of MRSA (P = 0.041)..
The prevalence of MRSA colonization upon ICU admission at our hospital was relatively high, and routine MRSA screening is suggested, especially for patients who have certain risk factors. In addition, extra-nasal MRSA screenings upon ICU admission will help in the early detection of MRSA.