The prevalence of methicillin-resistant Staphylococcus aureus among the residents of six nursing homes for the elderly

Admissions to Irish hospitals from nursing homes are recognized as a high-r isk category for methicillin-resistant Staphylococcus aureus (MRSA) coloniz ation. This study was conducted bt tn-een August 1991 and May 1995 to deter mine the prevalence of MRSA within six Eastern Health Board elderly care nu rsing homes. A point prevalence survey was conducted in each home on two se parate occasions at an interval of five to six months. An MRSA prevalence r ate of 8.6% (65 of 754 residents) was recorded for the first survey and an increased prevalence rate 10.1% (75 of 743 residents) for the second. The p revalence rates within individual homes varied from 1-27%. The body site mo st commonly colonized was the nares (83%), as anticipated. The main unexpec ted finding was a lon wound colonization rate of 12%, which increased to on ly 20% among MRSA positive residents. The dynamic state of MRSA colonizatio n within nursing homes was documented among the 587 residents screened in b oth surveys. The MRSA positive status of 19 residents remained unchanged, b ut 32 who were initially positive became negative, while 34 residents acqui red the organism. Twenty-six of the 56 (46%) residents identified as MRSA p ositive in the second survey had acquired the organism within the nursing h ome over the preceding five to six months. These findings suggest that 'inf ection control' interventions could have a significant impact on MRSA preva lence within nursing homes. (C) 2000 The Hospital Infection Society.