MRSA Prevalence and Decolonization in Long-Term Care Facilities (LTCFs) in Northern Israel

Background:

While MRSA is a well-known pathogen in healthcare settings, little is known about the effectiveness of MRSA carrier decolonization in high-prevalence, long-term care settings.

Objective:

To determine MRSA carrier prevalence among residents and staff of regional LTCFs during a suspected outbreak, and the effectiveness of decolonization. 

Methods:

Nasal swabs were obtained from residents and staff at 6 LTCFs during February-May 2009. MRSA was identified by direct plating on CHROMagar™ MRSA plates, and coagulase production. Definitive identification and antibiotic susceptibilities were determined by VITEK 2 and confirmed by PCR for the mecA gene.  The decolonization protocol consisted of intranasal mupirocin three times daily, and a daily wash with 4% chlorhexidine soap, both for 7 days.  The protocol was repeated once in the event of continued colonization on post-treatment MRSA screening, performed at least 1 week after the end of treatment.  Follow-up screening was performed after 3-6 months.  The proportion of successfully decolonized carriers who were still negative on follow-up screening was compared, via Fisher's exact test, with the proportion of carriers who spontaneously cleared carriage over a similar period of time without undergoing decolonization.

Results: 191 of 192 residents (99%), and 132 of 135 staff members (98%), in 6 regional LTCFs, were screened.  Median ages among those screened were 85 years (residents), and 49 years (staff).  MRSA was found in 27 residents (14%) and 14 staff members (11%).  Among residents, 12 of 24 (50%) had negative results on screening after initial decolonization treatment, and 5 of 9 (56%) had negative results on screening after subsequent treatment.  At follow-up screening of 12 residents successfully decolonized, 10 (83%) remained negative, compared with 5 of 14 (36%) who spontaneously cleared carriage (P=0.02). Among staff, 11 of 13 (85%) had negative results on screening after initial decolonization treatment, and 1 of 2 (50%) had negative results on screening after subsequent treatment.  At follow-up screening of 8 staff members successfully decolonized, 7 (88%) remained negative, compared with 2 of 5 (40%) who spontaneously cleared carriage (P=NS).       

Conclusions:

A high prevalence of MRSA carriage was found among residents and staff of LTCFs in northern Israel.  Active decolonization succeeded in lowering the MRSA burden at least in the short term, and likely lowered the chances of cross-transmission of MRSA.