Association of antimicrobial perioperative prophylaxis with cefuroxime plus metronidazole or amoxicillin/clavulanic acid and surgical site infections in colorectal surgery.

OBJECTIVE: To compare intravenous (IV) amoxicillin/clavulanic acid (A/CA) to IV cefuroxime plus metronidazole (C + M) for preventing surgical site infections (SSI) in colorectal surgery. BACKGROUND: Given their spectra that include most Enterobacterales and anaerobes, C + M is commonly recommended as prophylaxis of SSI in colorectal surgery. A/CA offers good coverage of Enterobacterales and anaerobes as well, but, in contrast to C + M, it also includes Enterococcus faecalis which is also isolated from patients with SSI and could trigger anastomotic leakage. METHODS: Data from a Swiss SSI surveillance program were used to compare SSI rates after class II (clean contaminated) colorectal surgery between patients who received C + M and those who received A/CA. We employed multivariable logistic regression to adjust for potential confounders, along with propensity score matching to adjust for group imbalance. RESULTS: From 2009 to 2018, 27,922 patients from 127 hospitals were included. SSI was diagnosed in 3132 (11.2%): 278/1835 (15.1%) in those who received A/CA and 2854/26,087 (10.9%) in those who received C + M (p < 0.001). The crude OR for SSI in the A/CA group as compared to C + M was 1.45 [CI 95% 1.21-1.75]. The adjusted OR was 1.49 [1.24-1.78]. This finding persisted in a 1:1 propensity score matched cohort of 1835 patients pairs with an OR of 1.60 [1.28-2.00]. Other factors independently associated with SSI were an ASA score > 2, a longer duration of operation, and a reoperation for a non-infectious complication. Protective factors were female sex, older age, antibiotic prophylaxis received 60 to 30 min before surgery, elective operation, and endoscopic approach. CONCLUSIONS: Despite its activity against enterococci, A/CA was less effective than C + M for preventing SSI, suggesting that it should not be a first choice antibiotic prophylaxis for colorectal surgery.

Surveillance quality correlates with surgical site infection rates in knee and hip arthroplasty and colorectal surgeries: A call to action to adjust reporting of SSI rates.

OBJECTIVE: The incidence of surgical site infections may be underreported if the data are not routinely validated for accuracy. Our goal was to investigate the communicated SSI rate from a large network of Swiss hospitals compared with the results from on-site surveillance quality audits. DESIGN: Retrospective cohort study. PATIENTS: In total, 81,957 knee and hip prosthetic arthroplasties from 125 hospitals and 33,315 colorectal surgeries from 110 hospitals were included in the study. METHODS: Hospitals had at least 2 external audits to assess the surveillance quality. The 50-point standardized score per audit summarizes quantitative and qualitative information from both structured interviews and a random selection of patient records. We calculated the mean National Healthcare Safety Network (NHSN) risk index adjusted infection rates in both surgery groups. RESULTS: The median NHSN adjusted infection rate per hospital was 1.0% (interquartile range [IQR], 0.6%-1.5%) with median audit score of 37 (IQR, 33-42) for knee and hip arthroplasty, and 12.7% (IQR, 9.0%-16.6%), with median audit score 38 (IQR, 35-42) for colorectal surgeries. We observed a wide range of SSI rates and surveillance quality, with discernible clustering for public and private hospitals, and both lower infection rates and audit scores for private hospitals. Infection rates increased with audit scores for knee and hip arthroplasty (P value for the slope = .002), and this was also the case for planned (P = .002), and unplanned (P = .02) colorectal surgeries. CONCLUSIONS: Surveillance systems without routine evaluation of validity may underestimate the true incidence of SSIs. Audit quality should be taken into account when interpreting SSI rates, perhaps by adjusting infection rates for those hospitals with lower audit scores.

Performance of surgical site infection risk prediction models in colorectal surgery: external validity assessment from three European national surveillance networks.

OBJECTIVE: To assess the validity of multivariable models for predicting risk of surgical site infection (SSI) after colorectal surgery based on routinely collected data in national surveillance networks. DESIGN: Retrospective analysis performed on 3 validation cohorts. PATIENTS: Colorectal surgery patients in Switzerland, France, and England, 2007-2017. METHODS: We determined calibration and discrimination (ie, area under the curve, AUC) of the COLA (contamination class, obesity, laparoscopy, American Society of Anesthesiologists [ASA]) multivariable risk model and the National Healthcare Safety Network (NHSN) multivariable risk model in each cohort. A new score was constructed based on multivariable analysis of the Swiss cohort following colorectal surgery, then based on colon and rectal surgery separately. RESULTS: We included 40,813 patients who had undergone elective or emergency colorectal surgery to validate the COLA score, 45,216 patients to validate the NHSN colon and rectal surgery risk models, and 46,320 patients in the construction of a new predictive model. The COLA score's predictive ability was poor, with AUC values of 0.64 (95% confidence interval [CI], 0.63-0.65), 0.62 (95% CI, 0.58-0.67), 0.60 (95% CI, 0.58-0.61) in the Swiss, French, and English cohorts, respectively. The NHSN colon-specific model (AUC, 0.61; 95% CI, 0.61-0.62) and the rectal surgery-specific model (AUC, 0.57; 95% CI, 0.53-0.61) showed limited predictive ability. The new predictive score showed poor predictive accuracy for colorectal surgery overall (AUC, 0.65; 95% CI, 0.64-0.66), for colon surgery (AUC, 0.65; 95% CI, 0.65-0.66), and for rectal surgery (AUC, 0.63; 95% CI, 0.60-0.66). CONCLUSION: Models based on routinely collected data in SSI surveillance networks poorly predict individual risk of SSI following colorectal surgery. Further models that include other more predictive variables could be developed and validated.

Structure, Process, and Outcome Quality of Surgical Site Infection Surveillance in Switzerland.

OBJECTIVE To assess the structure and quality of surveillance activities and to validate outcome detection in the Swiss national surgical site infection (SSI) surveillance program. DESIGN Countrywide survey of SSI surveillance quality. SETTING 147 hospitals or hospital units with surgical activities in Switzerland. METHODS Site visits were conducted with on-site structured interviews and review of a random sample of 15 patient records per hospital: 10 from the entire data set and 5 from a subset of patients with originally reported infection. Process and structure were rated in 9 domains with a weighted overall validation score, and sensitivity, specificity, positive predictive value, and negative predictive value were calculated for the identification of SSI. RESULTS Of 50 possible points, the median validation score was 35.5 (range, 16.25-48.5). Public hospitals (P<.001), hospitals in the Italian-speaking region of Switzerland (P=.021), and hospitals with longer participation in the surveillance (P=.018) had higher scores than others. Domains that contributed most to lower scores were quality of chart review and quality of data extraction. Of 49 infections, 15 (30.6%) had been overlooked in a random sample of 1,110 patient records, accounting for a sensitivity of 69.4% (95% confidence interval [CI], 54.6%-81.7%), a specificity of 99.9% (95% CI, 99.5%-100%), a positive predictive value of 97.1% (95% CI, 85.1%-99.9%), and a negative predictive value of 98.6% (95% CI, 97.7%-99.2%). CONCLUSIONS Irrespective of a well-defined surveillance methodology, there is a wide variation of SSI surveillance quality. The quality of chart review and the accuracy of data collection are the main areas for improvement. Infect Control Hosp Epidemiol 2017;38:1172-1181.

First Results of the Swiss National Surgical Site Infection Surveillance Program: Who Seeks Shall Find.

OBJECTIVES To report on the results of the Swiss national surgical site infection (SSI) surveillance program, including temporal trends, and to describe methodological characteristics that may influence SSI rates DESIGN Countrywide survey of SSI over a 4-year period. Analysis of prospectively collected data including patient and procedure characteristics as well as aggregated SSI rates stratified by risk categories, type of SSI, and time of diagnosis. Temporal trends were analyzed using stepwise multivariate logistic regression models with adjustment of the effect of the duration of participation in the surveillance program for confounding factors. SETTING The study included 164 Swiss public and private hospitals with surgical activities. RESULTS From October 2011 to September 2015, a total of 187,501 operations performed in this setting were included. Cumulative SSI rates varied from 0.9% for knee arthroplasty to 14.4% for colon surgery. Postdischarge follow-up was completed in >90% of patients at 1 month for surgeries without an implant and in >80% of patients at 12 months for surgeries with an implant. High rates of SSIs were detected postdischarge, from 20.7% in colon surgeries to 93.3% in knee arthroplasties. Overall, the impact of the duration of surveillance was significantly and independently associated with a decrease in SSI rates in herniorraphies and C-sections but not for the other procedures. Nevertheless, some hospitals observed significant decreases in their rates for various procedures. CONCLUSIONS Intensive post-discharge surveillance may explain high SSI rates and cause artificial differences between programs. Surveillance per se, without structured and mandatory quality improvement efforts, may not produce the expected decrease in SSI rates. Infect Control Hosp Epidemiol 2017;38:697-704.

Epidemiology of Staphylococcus aureus Surgical Site Infections.

BACKGROUND: Surgical site infections (SSI) due to Staphylococcus aureus are associated with substantial mortality rates and morbidity. Hence, various strategies are being investigated to prevent them. We explore time trends and risk factors associated with S. aureus SSI to identify high risk patients who might benefit the most from these strategies. METHODS: This is a retrospective cross-sectional study on a prospectively maintained database. We identified organism specific risk factors for S. aureus SSI as a whole, methicillin-sensitive S. aureus (MSSA), and methicillin-resistant S. aureus (MRSA). We also identified procedure-specific risk factors for S. aureus SSI for colectomy, hip, and knee arthroplasty, herniorrhaphy, and cholecystectomy. RESULTS: We compared 249 patients with S. aureus SSI with 54,988 uninfected control patients. The rate of S. aureus SSI was steady throughout the study period with MSSA being more common than MRSA. Independent risk factors for S. aureus SSI from multivariable analysis were length of hospitalization prior to surgery [odds ratio (OR) 1.01; 95% confidence interval (CI), 1.00-1.02)], colectomy (OR 2.81; 95% CI, 1.94-4.07), hip or knee arthroplasty (OR 1.52; 95% CI, 1.04-2.21), extended duration of surgery (OR 1.61; 95% CI, 1.10-2.37), NNIS score of two or more (OR 2.04; 95% CI, 1.24-3.36), and re-interventions for non-infectious reasons (OR 1.82; 95% CI, 1.16-2.86). Minimally invasive (OR 0.21; 95% CI, 0.13-0.34) and emergency operations (OR 0.61; 95% CI, 0.41-0.92) were protective against S. aureus SSI. CONCLUSIONS: Future S.aureus SSI prevention measures should focus on patients with risk profiles identified from this and other similar studies.

Surgical site infections in colon surgery: the patient, the procedure, the hospital, and the surgeon.

OBJECTIVE: To determine the role of the surgeon in the occurrence of surgical site infection (SSI) following colon surgery, with respect to his or her adherence to guidelines and his or her experience. DESIGN, SETTING, AND PATIENTS: Prospective cohort study of 2393 patients who underwent colon surgery performed by 31 surgeons in 9 secondary and tertiary care public Swiss hospitals, recruited from a surveillance program for SSI between March 1, 1998, and December 31, 2008, and followed up for 1 month after their operation. MAIN OUTCOME MEASURES: Risk factors for SSI were identified in univariate and multivariate analyses that included the patients' and procedures' characteristics, the hospitals, and the surgeons as candidate covariates. Correlations were sought between surgeons' individual adjusted risks, their self-reported adherence to guidelines, and the delay since their board certification. RESULTS: A total of 428 SSIs (17.9%) were identified, with hospital rates varying from 4.0% to 25.2% and individual surgeon rates varying from 3.7% to 36.1%. Features of the patients and procedures associated with SSI in univariate analyses were male sex, age, American Society of Anesthesiologists score, contamination class, operation duration, and emergency procedure. Correctly timed antibiotic prophylaxis and laparoscopic approach were protective. Multivariate analyses adjusting for these features and for the hospitals found 4 surgeons with higher risk of SSI (odds ratio [OR] = 2.37, 95% confidence interval [CI], 1.51-3.70; OR = 2.19, 95% CI, 1.41-3.39; OR = 2.15, 95% CI, 1.02-4.53; and OR = 1.97, 95% CI, 1.18-3.30) and 2 surgeons with lower risk of SSI (OR = 0.43, 95% CI, 0.19-0.94; and OR = 0.19, 95% CI, 0.04-0.81). No correlation was found between surgeons' individual adjusted risks and their adherence to guidelines or their experience. CONCLUSION: For reasons beyond adherence to guidelines or experience, the surgeon may constitute an independent risk factor for SSI after colon surgery.

Measures to prevent surgical site infections: what surgeons (should) do.

BACKGROUND: The present study was designed to evaluate surgeons' strategies and adherence to preventive measures against surgical site infections (SSIs). MATERIALS AND METHODS: All surgeons participating in a prospective Swiss multicentric surveillance program for SSIs received a questionnaire developed from the 2008 National (United Kingdom) Institute for Health and Clinical Excellence (NICE) clinical guidelines on prevention and treatment of SSIs. We focused on perioperative management and surgical technique in hernia surgery, cholecystectomy, appendectomy, and colon surgery (COL). RESULTS: Forty-five of 50 surgeons contacted (90%) responded. Smoking cessation and nutritional screening are regularly propagated by 1/3 and 1/2 of surgeons, respectively. Thirty-eight percent practice bowel preparation before COL. Preoperative hair removal is routinely (90%) performed in the operating room with electric clippers. About 50% administer antibiotic prophylaxis within 30 min before incision. Intra-abdominal drains are common after COL (43%). Two thirds of respondents apply nonocclusive wound dressings that are manipulated after hand disinfection (87%). Dressings are usually changed on postoperative day (POD) 2 (75%), and wounds remain undressed on POD 2-3 or 4-5 (36% each). CONCLUSIONS: Surgeons' strategies to prevent SSIs still differ widely. The adherence to the current NICE guidelines is low for many procedures regardless of the available level of evidence. Further research should provide convincing data in order to justify standardization of perioperative management.

Laparoscope use and surgical site infections in digestive surgery.

OBJECTIVE: To compare surgical site infection (SSI) rates in open or laparoscopic appendectomy, cholecystectomy, and colon surgery. To investigate the effect of laparoscopy on SSI in these interventions. BACKGROUND: Lower rates of SSI have been reported among various advantages associated with laparoscopy when compared with open surgery, particularly in cholecystectomy. However, biases such as the lack of postdischarge follow-up and confounding factors might have contributed to the observed differences between the 2 techniques. METHODS: This observational study was based on prospectively collected data from an SSI surveillance program in 8 Swiss hospitals between March 1998 and December 2004, including a standardized postdischarge follow-up. SSI rates were compared between laparoscopic and open interventions. Factors associated with SSI were identified by using logistic regression models to adjust for potential confounding factors. RESULTS: SSI rates in laparoscopic and open interventions were respectively 59/1051 (5.6%) versus 117/1417 (8.3%) in appendectomy (P = 0.01), 46/2606 (1.7%) versus 35/444 (7.9%) in cholecystectomy (P < 0.0001), and 35/311 (11.3%) versus 400/1781 (22.5%) in colon surgery (P < 0.0001). After adjustment, laparoscopic interventions were associated with a decreased risk for SSI: OR = 0.61 (95% CI 0.43-0.87) in appendectomy, 0.27 (0.16-0.43) in cholecystectomy, and 0.43 (0.29-0.63) in colon surgery. The observed effect of laparoscopic techniques was due to a reduction in the rates of incisional infections, rather than in those of organ/space infections. CONCLUSION: When feasible, a laparoscopic approach should be preferred over open surgery to lower the risks of SSI.

Administrative data outperformed single-day chart review for comorbidity measure.

OBJECTIVE: The purpose of this article is to compare the Charlson comorbidity index derived from a rapid single-day chart review with the same index derived from administrative data to determine how well each predicted inpatient mortality and nosocomial infection. DESIGN: Cross-sectional study. SETTING: The study was conducted in the context of the Swiss Nosocomial Infection Prevalence (SNIP) study in six hospitals, canton of Valais, Switzerland, in 2002 and 2003. PARTICIPANTS: We included 890 adult patients hospitalized from acute care wards. MAIN OUTCOME MEASURES: The Charlson comorbidity index was recorded during one single-day for the SNIP study, and from administrative data (International Classification of Disease, 10th revision codes). Outcomes of interest were hospital mortality and nosocomial infection. RESULTS: Out of 17 comorbidities from the Charlson index, 11 had higher prevalence in administrative data, 4 a lower and two a similar compared with the single-day chart review. Kappa values between both databases ranged from - 0.001 to 0.56. Using logistic regression to predict hospital outcomes, Charlson index derived from administrative data provided a higher C statistic compared with single-day chart review for hospital mortality (C = 0.863 and C = 0.795, respectively) and for nosocomial infection (C = 0.645 and C = 0.614, respectively). CONCLUSIONS: The Charlson index derived from administrative data was superior to the index derived from rapid single-day chart review. We suggest therefore using administrative data, instead of single-day chart review, when assessing comorbidities in the context of the evaluation of nosocomial infections.