Methicillin-resistant Staphylococcus aureus infection rate after implementation of an antibiotic care bundle based on results of rapid molecular screening

Abstract

Aim: Colonization with methicillin-resistant Staphylococcus aureus (MRSA) is a risk factor for subsequent invasive MRSA infection, particularly in patients admitted to critical areas. We conducted a surveillance among patients admitted to our Intensive Care Unit (ICU) to determine whether the implementation of a specific MRSA antibiotic care bundle (ACB) based on rapid molecular screening for MRSA and de-colonization, reduced the total MRSA infection rate.

Materials and methods: A total of 431 and 577 nasal swabs were obtained from ICU patients at admission from April 2009 through December 2010 (pre-ACB period) and, after the bundle implementation, from January 2011 through December 2012 (post-ACB period), respectively. Nasal swabs were analyzed by the rapid molecular test Xpert MRSA. All patients were followed-up during their whole ICU stay to determine whether they developed MRSA infection.

Results: Overall, 31 out of 431 (7.1%) patients were colonized with MRSA at admission during the pre-ACB period and 49 out of 577 (8.4%) were colonized with MRSA during the post-ACB period. The rate of MRSA infection in ICU significantly declined from 2% in pre-ACB to 0.3% in post-ACB, with a total decrease of 100% in two consecutive semesters between July 2011 and July 2012 (p<0.001).

Conclusion: The analysis demonstrated a significant decline in MRSA infections following the introduction of active rapid molecular surveillance and the specific ACB at our ICU and in the risk associated with MRSA bacteremia.

Keywords: Rapid molecular screening; Staphylococcus aureus; infection prevention; methicillin-resistant; nosocomial infection.