Screening, Decolonization are Effective Interventions for Decreasing MRSA Burden

In November 2004, a national target was set for hospitals in England to reduce the methicillin-resistant Staphylococcus aureus (MRSA) bactermia rate by 60 percent by April 2008 against the number during 2003/04 (baseline year). Sarma, et al. (2013) report that in their organization the number of MRSA bactermias has risen since 2002 and peaked at 75 in 2005/06. A target was set to reduce the number and string of specific and non-specific interventions was introduced including universal MRSA screening. This study analyzes the impact of universal MRSA screening using a quasi-experimental design using routinely gathered data.
 
This study used data gathered routinely for clinical governance, quality control, financial management and outbreak monitoring purposes. Interrupted Time Series (ITS) analysis of 15 pre- and 19 post- universal MRSA screening (and decolonization) quarterly numbers of bactermias was carried out where methicillin-sensitive Staphylococcus aureus (MSSA) numbers served as non-equivalent dependent variable (control).
 
An immediate sharp decrease in MRSA bactermias was observed following the universal MRSA screening (and decolonization) commenced in Q2, 2007. The number dropped sharply from 23 (Q2, 2007) to 10 (Q3, 2007) all MRSA bactermias, and, from 15 (Q2, 2007) to 6 (Q3, 2007) for bactermias >= 48 hours of hospitalization. The declining trend continued reaching zero in Q2, 2009 and Q4, 2010 for those with >=48 hours of hospitalization and, all bactermias, respectively. ITS analysis revealed significant impact of universal MRSA screening on all MRSA bactermias (beta2 -0.554, p 0.000) and those with >=48 of hospitalization (beta2 -0.577, p 0.001), respectively. Impact estimation predicted 17 and 13 bactermias for all and those with >=48 hours hospitalization, respectively in the 19th quarter post-intervention, if the intervention did not occur. The number of MRSA isolates from non-blood culture systemic sources as percentage of admissions also dropped significantly from 3.32 percent in Q2, 2007 to 1.51 percent in Q3, 2007 (beta2 -0.506, p 0.000) which is still running low at 0.33 percent at the end of Q1, 2012. On the other hand, there was no statistically significant impact of universal screening on MSSA bactermias.
 
The researchers conclude that of all interventions, the universal MRSA screening (and decolonization) is the most effective intervention associated with significant and sharp drop in MRSA burden. Their research was published in Antimicrobial Resistance and Infection Control. 

Reference: Sarma JB, Marshall B, Cleeve V, Tate D and Oswald T. Impact of universal screening on MRSA bactermias in a single acute NHS organisation (2006--12): interrupted time-series analysis  Antimicrobial Resistance and Infection Control 2013, 2:2 doi:10.1186/2047-2994-2-2