Abstract
Surveillance culture surveys targeting methicillin-resistant Staphylococcus aureus (MRSA) are often conducted at high-risk wards such as intensive care units. The surveillance culture strategies vary depending on the conditions at each institute, but cost-effectiveness should be considered on the individual institute basis to avoid excessive labor and financial costs. In our hospital, the numbers of culture specimens increased 1.5 times every year from 2005 to 2010. Among the various types of culture specimens, the numbers of feces and nasal swabbing samples increased more sharply, suggesting increased frequencies of surveillance cultures. This trend was most prominently observed in the neonatal intensive care unit (NICU), so how surveillance culture was performed in the NICU was further investigated. In 2008, when MRSA isolations increased in the NICU, weekly examination of both feces and nasal swabbing specimens started routinely for all hospitalized infants. However, this surveillance method seemed not to be optimally cost-effective, because retrospective analysis of MRSA isolations revealed that MRSA was usually identified in both samples at the same time and colonized afterward in most infants carrying MRSA. Therefore, we changed the surveillance culture strategy in 2011 to limit surveillance culture specimens to nasal swabbing, and once MRSA had colonized, surveillance culture was discontinued. These changes resulted in 32% reduction of sample numbers with estimated 74% cost savings for surveillance culture per year. In conclusion, epidemiological analyses can help to improve the cost-effectiveness of surveillance culture surveys.
