An antibiotic care bundle approach based on results of rapid molecular screening for nasal carriage of methicillin-resistant Staphylococcus aureus in the intensive care unit.

The potential role of active methicillin-resistant Staphylococcus aureus (MRSA) surveillance in the intensive care unit (ICU), has been recently proposed as a guide for antibiotic treatment in patients suspected of being infected with MRSA by using an antibiotic care bundle (ACB) approach. A group of 376 consecutive ICU patients were prospectively screened for nasal carriage of MRSA using a real-time polymerase chain reaction test. The study group consisted of 244 (64.9%) males and (35.1%) females, with a median age of 64 (range 17-95 years). Overall, 26 (6.9%) patients were positive for MRSA, while 350 (93.1%) were MRSA-negative. No difference was observed in gender and age between groups. During ICU stay, 9 (2.4%) patients developed generalized MRSA infection, of whom 8 out of 26 (30.8%) were MRSA-carriers and one out of the 350 (0.3%) was MRSA-negative. Thus, a strong relationship between MRSA infection and MRSA carriage (relative risk=107.7, 95% confidence interval=14.0-828.5, p<0.0001) was found. Subsequently, in our ICU, we developed and introduced a new ACB approach based on rapid nasal screening results for improving the management of critically ill patients. The use of anti-MRSA agents should be re-evaluated daily on the basis of clinical and laboratory features, with positive cultures from sterile site or signs of active infection supporting prolongation of empirical treatment. On the contrary, MRSA-negative clinical cultures support a de-escalation strategy. In conclusion, the early identification of MRSA-carriers using a rapid molecular screening is safe and accurate, allowing MRSA-positive patients, who will more likely develop MRSA infections, to be detected.