To describe the results of the first year of the Dutch national surveillance of surgical-site infections (SSIs) and risk factors, which aims to implement a standardized surveillance system in a network of Dutch hospitals, to collect comparable data on SSIs to serve as a reference, and to provide a basic infrastructure for further intervention research.

Prospective multicenter cohort study.

Acute-care hospitals in The Netherlands from June 1996 to May 1997.

38 hospitals participated, with a slight overrepresentation of larger hospitals. Following a total of 18,063 operations, 562 SSIs occurred, of which 198 were deep. Multivariate analysis of pooled procedures shows that age, preoperative length of stay, wound contamination class, anesthesia score, and duration of surgery were independent risk factors for SSI. When analyzed by procedure, the relative importance of these risk factors changed. Bacteriological documentation was available for 56% of the SSIs; 35% of all isolates were Staphylococcus aureus. Multiple regression analysis computed the mean extra postoperative length of stay associated with SSI to be 8.2 days.

The first year of national surveillance has shown that it is feasible to collect comparable data on SSI, which are already used for education, policy, and decision making in the network of participating hospitals. This gives room to effectuate the next aim, namely to use the network as an infrastructure for intervention research. Multivariate analysis shows that feedback on a procedure-specific level is important.

To determine the relative importance of different risk factors for the development of surgical-site infections (SSIs) in orthopedic surgery with prosthetic implants.

In a cohort of 272 patients, the following possible risk factors were studied: age, gender, method of hair removal, duration of operation, surgeon, underlying illness, and nasal carriage of Staphylococcus aureus. Infections were recorded following the Centers for Disease Control criteria. The relation between risk factors and SSI was tested in univariate and multiple logistic regression analysis.

Community hospital in Breda, The Netherlands.

18 (6.6%) of 272 patients experienced SSI: 11 superficial and 7 deep SSI. These infections led in three cases to removal of the prosthesis and caused 286 extra days in hospital. The main causative pathogen was S aureus. In multiple logistic regression analysis, the following factors were independent risk factors for the development of SSI: high-level nasal carriage of S aureus (P=.04), male gender (P=.005), and surgeon 1 (P=.006). The only independent risk factor for SSI with S aureus was high-level nasal carriage of S aureus (P=.002).

High-level nasal carriage of S aureus was the most important and only significant independent risk factor for developing SSI with S aureus.

To investigate whether the correlation between patients' antibiotic treatment (yes/no) and patients' infections (yes/no) in each hospital department, described by Pearson's correlation coefficient (ρ) for binary data as a measure for adequate use of antibiotics, is an appropriate quality indicator.

Comparison of the results of repeated prevalence studies in different hospitals with the data of a national prevalence study, comparing the hospital (ρ) and reference (ρNIDHP[Nosokomiale Infektionen in Deutschland: Erfassung und Prävention]) correlation coefficients for “use of antibiotics/ presence of infections.”

The data of 5,377 surgical patients were separated from the total data of a national prevalence study in 72 representative hospitals to create a reference correlation coefficient (ρNIDEP) with a reference range. Nine additional prevalence studies, involving a total of 4,984 patients, were repeatedly performed in the surgical departments of 8 other hospitals during a 12-month period, whereby the correlation coefficients ρn for every prevalence investigation were determined.

In the national prevalence study, 15.3% of the surgical patients received antibiotics on the study day. Surgical patients had a 3.8% prevalence of nosocomial infections and a 7.0% prevalence of community-acquired infections. Pearson's correlation coefficient ρNIDEP for correlation between patients' binary data use of antibiotics and presence of infection was 0.62. To compare the correlation coefficient of each department with the appropriate reference range, the coefficients of the single departments were plotted against the number of patients; in these plots, three lines indicated the value ρNIDEP and the upper and lower reference ranges, depending on the number of patients. Seven of eight surgical departments investigated during the repeated prevalence studies were found to be within the reference range, near the reference value, in the majority of prevalence studies; only one of the departments was identified as an outlier as regards antibiotic use.

The correlation between patients' antibiotic treatment (yes/no) and patients' infections (yes/no) in hospitals or departments, as described by Pearson's correlation coefficient ρ for binary data with a definitive reference range depending on the number of patients, is useful for quality management in identifying the overall necessity for evaluating the indications for antibiotic use in one's own hospital.