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-risk category for methicillin-resistant Staphylococcus aureus (MRSA) colonization. This study was conducted between August 1994 and May 1995 to determine the prevalence of MRSA within six Eastern Health Board elderly care nursing homes. A point prevalence survey was conducted in each home on two separate occasions at an interval of five to six months. An MRSA prevalence rate 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 prevalence rates within individual homes varied from 1-27%. The body site most commonly colonized was the nares (83%), as anticipated. The main unexpected finding was a low wound colonization rate of 12%, which increased to only 20%, among MRSA positive residents. The dynamic state of MRSA colonization within nursing homes was documented among the 587 residents screened in both surveys. The MRSA positive status of 19 residents remained unchanged, but 32 who were initially positive became negative, while 34 residents acquired the organism. Twenty-six of the 56 (46%) residents identified as MRSA positive in the second survey had acquired the organism within the nursing home over the preceding five to six months. These findings suggest that 'infection control' interventions could have a significant impact on MRSA prevalence within nursing homes.