Transmission of methicillin-resistant Staphylococcus aureus to household contacts

Abstract

The frequency of and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) transmission from a MRSA index person to household contacts were assessed in this prospective study. Between January 2005 and December 2007, 62 newly diagnosed MRSA index persons (46 patients and 16 health care workers) and their 160 household contacts were included in the study analysis. Transmission of MRSA from an index person to household contacts occurred in nearly half of the cases (47%; n = 29). These 29 index persons together had 84 household contacts, of which two-thirds (67%; n = 56) became MRSA positive. Prolonged exposure time to MRSA at home was a significant risk factor for MRSA transmission to household contacts. In addition, MRSA colonization at least in the throat, younger age, and eczema in index persons were significantly associated with MRSA transmission; the presence of wounds was negatively associated with MRSA transmission. Furthermore, an increased number of household contacts and being the partner of a MRSA index person were household-related risk factors for MRSA acquisition from the index person. No predominant pulsed-field gel electrophoresis (PFGE) type was observed to be transmitted more frequently than other PFGE types. To date, screening household contacts and providing MRSA eradication therapy to those found positive simultaneously with the index person is not included in the "search-and-destroy" policy. We suggest including both in MRSA prevention guidelines, as this may reduce further spread of MRSA.

FIG. 1.

Rates of MRSA colonization of sites in 62 MRSA-positive index persons. n, nose only; t, throat only; p, perineum only; o, other only; nt, nose + throat; np, nose + perineum; no, nose + other; tp, throat + perineum; po, perineum + other; ntp, nose + throat + perineum; nto, nose + throat + other; tpo, throat + perineum + other; npo, nose + perineum + other; ntpo, nose + throat + perineum + other.