The endogenous pathway is a major route for deep sternal wound infection

Objective: Deep wound infections pose an increasing problem in cardiac surg ery patients. Prospective infection monitoring is thus a means of identifyi ng possible risk factors. Methods: Within a period of 5 months, a total of 376 adult patients, 260 men and 116 women, with a mean age of 62.6 years (r ange 18-88), underwent coronary bypass grafting (n = 281) or other cardiac surgery procedures (n = 95). Nasal cultures were taken preoperatively from every patient, as well as cultures of the wound during surgery and when dre ssings were changed thereafter. In addition, nasal cultures were taken from all the medical and nursing staff. To differentiate endogenous and exogeno us infection pathways, DNA fingerprint analysis was performed. Results: A t otal of 38 patients (10.1%) developed a wound infection, in 14 patients thi s happened to be a deep wound infection, in 24 patients a superficial one. Five sternal wound infections were associated with mediastinitis (1.3%). Th e occurrence of a wound infection overall resulted in prolonged hospitaliza tion (29.4 +/- 24 vs. 11.9 +/- 6.9 days, P = 0.001), but not in increased h ospital mortality (4.4% vs. 3.9%). Obesity, diabetes mellitus and nasal car riage of Staphylococcus aureus proved to be independent risk factors with a n odds ratio of 2.07, 2.26 and 2.28, respectively. In all but one of the st ernal colonizations with S. aureus, DNA fingerprint analysis demonstrated a n identical pattern of S. aureus from the patient's nose and sternum, indic ating an endogenous infection pathway. Conclusions: The determination of th e endogenous pathway for severe wound infection makes prevention possible b y means of preoperative local S. aureus eradication. (C) 2000 Elsevier Scie nce B.V. All rights reserved.