Active surveillance and decolonization of MRSA carriers as a tool for MRSA bacteremia reduction

1. Active surveillance and decolonization of MRSA carriers as a tool for MRSA bacteremia reduction B. CHAZAN, N. TEITLER, R. COLODNER, O. NITZAN, H. EDELSTEIN, R. RAZ Ha’ Emek Medical Center Afula Israel

2. Abstract: • Background: • Methicillin resistant Staphylococcus aureus (MRSA) is endemic in Israel's hospitals. Patients (pts) colonized with MRSA are a reservoir for spreading the bacteria and self infection. Active surveillance (AS) is an infection control measure used in order to reduce MRSA invasive infection. • Since 2001 we conducted an-ongoing bacteremia (B) surveillance in our hospital, and noticed a continuous rise in MRSA B rates: 22.9%, 16.7%, 30.8%, 32.7%, 36.8% (2001 to 2005). • Material and methods: • The study was conducted at the Ha’Emek Medical Center, a community teaching hospital in northern Israel serving a population of ~500,000 inhabitants. • An AS of MRSA carriers was implemented since 2004. Risk groups for MRSA colonization at admission were defined: long term care facility residents (LTCFR) and pts. hospitalized in the prior 3 months. • Nostrils, peri-anal and armpit cultures were obtained, and contact isolation was implemented pending results. Decolonization (DC) protocol was applied to MRSA carriers. • Results: • MRSA carriers were found in 25% of LTCFR, 20% and 33% of readmission pts. (from our & other hospitals respectively). >90% of the carriers were identified by nose and peri-anal cultures without additional benefit of armpits cultures, thus policy was changed to nose and peri-anal swabs alone. DC procedures were carried out in pts during hospitalization. • Following the intervention the rate of MRSA B decline from 32.7% (2004) to 10.3% (2007) (p<0.01). • Conclusions: • Ongoing B surveillance is an excellent tool to identify changes in antimicrobial susceptibilities • Nasal and peri-anal swab cultures identified most MRSA carriers • Contact isolation and DC of MRSA carriers contributed to the decrease of MRSA B rates • Infection control measures are mandatory in order to keep lower levels of MRSA B

3. Background: • Methicillin resistant Staphylococcus aureus (MRSA) is endemic in Israel's hospitals. Patients colonized with MRSA are a reservoir for spreading the bacteria and become infected themselves. • Active surveillance is one of the infection control measures that aim to reduce the level of MRSA distribution and invasive infection. • Since 2001 we conducted an-ongoing bacteremia surveillance in our hospital, and noticed a continuous rise in MRSA B rates: 22.9%, 16.7%, 30.8%, 32.7%, 36.8% (2001 to 2005).

4. Objectives: • Active surveillance : to identify patients colonized with Methicillin resistant Staphylococcus aureus (MRSA) at admission. • To implement a policy of : • Contact isolation of high risk patients for MRSA colonization (until culture results were obtained) • Decolonization of patients with MRSA positive cultures . • To evaluate if a “search and destroy policy” is an effective tool to stop the increase in MRSA bacteremia rates.

5. Methods: • The study was conducted at the Ha’Emek Medical Center, a community teaching hospital in northern Israel serving a population of ~500,000 inhabitants. • An active surveillance of MRSA carriers was implemented since 2004. • Risk groups for MRSA colonization at admission were defined: • Long term care facility residents. • Prior hospitalized in in another hospital (3 months). • Readmission from our hospital ( 3 months). • Nostrils, peri-anal and armpit cultures were obtained. • Contact isolation in the patientws room was implemented pending results. • Decolonization protocol was applied to MRSA carriers • Nasal Mupirocin twice daily for 5 days in each nostril • Daily shower with chlorhexidine gluconate 4% • All consecutives episodes of Staphylococcus aureus bacteremia (MSSA and MRSA) since 1.1.2001 until 31.12.2007 were registered.

6. Results • The rate of MRSA colonization was: • 25% in long term care facility residents. • 20% in readmitted patients. • 33% in patients hospitalized previously in another hospital. • Nose and perianal cultures identified more than 90% of MRSA carriers, while armpits did not improve the sensitivity of the surveillance. • No significant changes were observed in the rate of S. aureus bacteremia (11.2% in 2001, 9.2 % in 2007). • Decontamination procedures were carried out in all hospitalized patients identified as MRSA carriers. • Following the intervention the rate of MRSA bacteremia decline from 32.7% (2004) to 10.3% (2007) (p<0.01).

7. Frequency of bacteremia by year 2001-2007: all isolates Vs. S. aureus (MSSA and MRSA) (N.S. for all)

8. Frequency of S. aureus bacteremia by year 2001-2007: % of MSSA Vs MRSA isolates *p= 0.01 between 2004 and 2007

9. Conclusions: • Ongoing bacteremia surveillance is an excellent tool to identify changes in antimicrobial susceptibilities • No significant changes were found in the frequency of bacteremic isolates as in the rate of S. aureus bacteremia through seven years surveillance. • The rate of MRSA colonization was lower in readmitted patients, higher in long term care facility residents and highest in patients coming from another hospital. • Nasal and peri-anal swab cultures identified most MRSA carriers. • A policy of “search and destroy” (contact isolation and decontamination of MRSA carriers) contributed not only to halt the increasing rate in MRSA bacteremic isolates but to decrease this worrisome trend. • Infection control measures are mandatory in order to keep these lower levels of MRSA bacteremia.