Risk Factors for Staphylococcus aureus Colonization in a Cardiac Surgery Population

• Published in: American journal of infection control Vol. 32; no. 3; p. E119
• Main Authors: Hopkins-Broyles∗, D., Rieger, Y., Grim, A., Nihill, D., Jones, M., Damiano, R., Warren, D.K., Fraser, V.J.
• Format: Journal Article
• Language: English
• Published: Mosby, Inc 01.05.2004
• ISSN: 0196-6553; 1527-3296
• DOI: 10.1016/j.ajic.2004.04.176

BACKGROUND/OBJECTIVES: The objective of this project was to identify the prevalence of methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) carriage among cardiac surgery patients and to identify associated risk factors for MSSA and MRSA colonization. METHODS: Nasal swab cultures for MSSA and MRSA were obtained on 173/238 (73%) patients admitted to Barnes-Jewish hospital (BJH) for cardiac surgery from September through December 2002. Patients were swabbed the day of surgery in the pre-operative holding area. Variables were collected by retrospective chart review to determine medical and healthcare exposure risk factors associated with MSSA /MRSA colonization for 34 cases compared to all 139 culture-negative patients identified during the swabbing period. Univariate analysis was performed using Chi-square and Fisher's Exact to test for statistical significance. RESULTS: Of patients tested 34/173 (20%) were colonized with S. aureus; 27/173 (16%) were colonized with MSSA; 7/173 (4%) were colonized with MRSA. Analysis identified no risk factors that were associated with S. aureus colonization. Congestive heart failure (p= 0.27), chronic obstructive pulmonary disease (p= 0.13), renal failure (p=0.42), diabetes (p=0.55), and hospitalization in the past 12 months (p= 0.39) were similar in patients with and without MRSA. Steroid use within 30 days of admission (p= 0.02), presence of an invasive device (central line, dialysis catheter, defibrillator, prosthetic joint) (p= 0.01), and long-term/group home residence (p= 0.001) were significantly associated with MRSA colonization. CONCLUSIONS: The percent of BJH cardiac surgery patients colonized with MSSA and MRSA was lower than reported in the literature. Risk factors associated with MRSA colonization were similar to the literature. Identification of risk factors for colonization with MSSA/MRSA in specific patient populations could be useful to enhance surgical antibiotic prophylaxis.