Effect of Active Surveillance Intervention on Incidence of Methicillin-Resistant Staphylococcus aureus (MRSA)Infections in Surgical Intensive Care Unit

• Main Authors: Jen-Zon Chen, 陳貞蓉
• Other Authors: Chi-Tai Fang
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/73231251735380219333

碩士 === 國立臺灣大學 === 流行病學與預防醫學研究所 === 100 === Background and aim: Methicillin-resistant Staphylococcus aureus (MRSA) is a one of the leading pathogens in healthcare-associated infections. Patients with healthcare-associated MRSA infections suffer increased mortality and morbidity, as well as prolonged hospital stays and extra medical costs. Strategies to prevent systemic S. aureus infections by eliminating nasal carriage of S. aureus have been proposed, as a substantial proportion of S. aureus bacteremia cases appear to be of endogenous origin from colonies in the nasal mucosa. A recent randomized controlled trial conclusively showed that active surveillance to identify asymptomatic MRSA carriers followed by MRSA eradication can effectively reduce surgical-site MRSA infection rates. Nevertheless, whether similar intervention strategies can also reduce MRSA infections in non-RCT daily practice remains unclear. This study aimed to evaluate the effectiveness of routine active surveillance culture followed by a mupirocin treatment of MRSA carriers in controlling healthcare–associated MRSA infections in surgical ICU patients. Methods: This retrospective cohort study was conducted in the surgical intensive care unit (SICU) of a tertiary care, university-affiliated teaching hospital in northern Taiwan. This hospital has a 702-bed capacity, with 18 beds (all single-bed rooms) in the SICU. The study was conducted from January 2007 through September 2010. The intervention consisted of active surveillance cultures from the anterior nares of all patients admitted to the SICU for the identification of asymptomatic MRSA carriers. When the nasal swab culture was positive for MRSA, the MRSA was eradicated by administration of mupirocin ointment to the nares three times a day for 5 days, and the skin was decolonized with 4% chlorhexidine gluconate once daily for 5 days. Contact precautions were also employed,” if this maintains the intended meaning. The study period was divided into four stages. The first period (from January to September 2007) was the baseline period, and no active intervention was conducted. Contact precautions, eradication and environmental disinfection before patient discharge were performed only when clinical cultures were positive for MRSA. Active intervention, which was supported by a research grant from the hospital, was initiated at the start of the second period, lasting from October 2007 through April 2008. The intervention was halted in the third period (from May 2008 through August 2009), due to a lack of research grants. The intervention was resumed in the fourth period (from September 2009 through September 2010) after a surge in the SICU MRSA infection rate in the third period prompted the hospital leadership to provide financial support for active MRSA interventions. We compared healthcare-associated MRSA infection rates between patients admitted during the intervention and non-intervention periods. We further surveyed the Department of Health Death registry database and the National Health Insurance database to obtain information on 1-year outcomes. All causes of 1-year mortality and severe morbidity rates in patients admitted during the intervention and non-intervention periods were analyzed. Severe morbidity was defined as the onset of permanent dialysis or ventilator dependence registered with a catastrophic illness card by the National Health Insurance. Results: During the study period, a total of 2373 patients were admitted to the SICU. The MRSA infection rate in the surgical ICU was 3.58‰ (period 1), 0.42‰ (period 2), 2.21‰ (period ), and 0.18‰ (period 4). Multiple logistic regression analysis showed that intervention is an independent protective factor for MRSA infection in ICUs (adjusted odds ratio [OR]: 0.1, 95% CI, 0.02-0.4), after adjusting for the effects of potential confounding factors. The in-hospital MRSA infection rates was 1.42‰ (period 1), 0.29‰ (period 2), 0.75‰ (period ), and 0.24‰ (period 4). Multiple logistic regression analysis showed that intervention is an independent protective factor for in-hospital MRSA infection (adjusted OR: 0.3, 95% CI, 0.1-0.8), after adjusting for the effects of potential confounding factors. The time to mortality or to the onset of severe morbidity in the patients admitted during periods 1 and 2 were analyzed by multiple Cox regression analysis, which showed that intervention is an independent protective factor for mortality or the onset of severe morbidity (adjusted hazard ratio [HR]: 0.4, 95% CI, 0.3-0.6), after adjusting for the effects of potential confounding factors. The median costs of SICU hospitalization for patients with healthcare-associated MRSA infections were NT $754,845, an excess of NT $640,000 in comparison with patients without healthcare-associated MRSA. The number of MRSA cases averted by the intervention was estimated to be 13 during the intervention period. For every dollar spent on interventions, $30 can be saved in medical costs. Conclusion: Our study results showed that routine active surveillance and MRSA eradication in the SICU can effectively reduce MRSA infection rates, mortality, and the onset of severe morbidity, as well as medical costs. We recommend routine active surveillance and eradication intervention in SICUs to increase patient safety and enhance the quality of medical services.