Author(s): Burton DC, Edwards JR, Horan TC, Jernigan JA, Fridkin SK
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Abstract CONTEXT: Concerns about rates of methicillin-resistant Staphylococcus aureus (MRSA) health care-associated infections have prompted calls for mandatory screening or reporting in efforts to reduce MRSA infections. OBJECTIVE: To examine trends in the incidence of MRSA central line-associated bloodstream infections (BSIs) in US intensive care units (ICUs). DESIGN, SETTING, AND PARTICIPANTS: Data reported by hospitals to the Centers for Disease Control and Prevention (CDC) from 1997-2007 were used to calculate pooled mean annual central line-associated BSI incidence rates for 7 types of adult and non-neonatal pediatric ICUs. Percent MRSA was defined as the proportion of S aureus central line-associated BSIs that were MRSA. We used regression modeling to estimate percent changes in central line-associated BSI metrics over the analysis period. MAIN OUTCOME MEASURES: Incidence rate of central line-associated BSIs per 1000 central line days; percent MRSA among S. aureus central line-associated BSIs. RESULTS: Overall, 33,587 central line-associated BSIs were reported from 1684 ICUs representing 16,225,498 patient-days of surveillance; 2498 reported central line-associated BSIs (7.4\%) were MRSA and 1590 (4.7\%) were methicillin-susceptible S. aureus (MSSA). Of evaluated ICU types, surgical, nonteaching-affiliated medical-surgical, cardiothoracic, and coronary units experienced increases in MRSA central line-associated BSI incidence in the 1997-2001 period; however, medical, teaching-affiliated medical-surgical, and pediatric units experienced no significant changes. From 2001 through 2007, MRSA central line-associated BSI incidence declined significantly in all ICU types except in pediatric units, for which incidence rates remained static. Declines in MRSA central line-associated BSI incidence ranged from -51.5\% (95\% CI, -33.7\% to -64.6\%; P < .001) in nonteaching-affiliated medical-surgical ICUs (0.31 vs 0.15 per 1000 central line days) to -69.2\% (95\% CI, -57.9\% to -77.7\%; P < .001) in surgical ICUs (0.58 vs 0.18 per 1000 central line days). In all ICU types, MSSA central line-associated BSI incidence declined from 1997 through 2007, with changes in incidence ranging from -60.1\% (95\% CI, -41.2\% to -73.1\%; P < .001) in surgical ICUs (0.24 vs 0.10 per 1000 central line days) to -77.7\% (95\% CI, -68.2\% to -84.4\%; P < .001) in medical ICUs (0.40 vs 0.09 per 1000 central line days). Although the overall proportion of S. aureus central line-associated BSIs due to MRSA increased 25.8\% (P = .02) in the 1997-2007 period, overall MRSA central line-associated BSI incidence decreased 49.6\% (P < .001) over this period. CONCLUSIONS: The incidence of MRSA central line-associated BSI has been decreasing in recent years in most ICU types reporting to the CDC. These trends are not apparent when only percent MRSA is monitored.
This article was published in JAMA
and referenced in Epidemiology: Open Access