original article Diminishing Surgical Site Infections in Australia: Time Trends in Infection Rates, Pathogens and Antimicrobial Resistance Using a Comprehensive Victorian Surveillance Program, 2002–2013 Leon J. Worth, MBBS, FRACP; Grad Dip Epi, PhD; Ann L. Bull, PhD, M.App.Epid; Tim Spelman, BSc, MBBS; Judith Brett, BN; Michael J. Richards, MBBS, FRACP, MD OBJECTIVE . To evaluate time trends in surgical site infection (SSI) rates and SSI pathogens in Australia. design. Prospective multicenter observational cohort study. setting. A group of 81 Australian healthcare facilities participating in the Victorian Healthcare Associated Infection Surveillance System (VICNISS). patients. All patients underwent surgeries performed between October 1, 2002, and June 30, 2013. National Healthcare Safety Network SSI surveillance methods were employed by the infection prevention staff at the participating hospitals. intervention. Procedure-specific risk-adjusted SSI rates were calculated. Pathogen-specific and antimicrobial-resistant (AMR) infections were modeled using multilevel mixed-effects Poisson regression. results. A total of 183,625 procedures were monitored, and 5,123 SSIs were reported. Each year of observation was associated with 11% risk reduction for superficial SSI (risk ratio [RR], 0.89; 95% confidence interval [CI], 0.88–0.90), 9% risk reduction for deep SSI (RR, 0.91; 95% CI, 0.90–0.93), and 5% risk reduction for organ/space SSI (RR, 0.95; 95% CI, 0.93–0.97). Overall, 3,318 microbiologically confirmed SSIs were reported. Of these SSIs, 1,174 (35.4%) were associated with orthopedic surgery, 827 (24.9%) with coronary artery bypass surgery, 490 (14.8%) with Caesarean sections, and 414 (12.5%) with colorectal procedures. Staphylococcus aureus was the most frequently identified pathogen, and a statistically significant increase in infections due to ceftriaxone-resistant Escherichia coli was observed (RR, 1.37; 95% CI, 1.10–1.70). conclusions. Standardized SSI surveillance methods have been implemented in Victoria, Australia. Over an 11-year period, diminishing rates of SSIs have been observed, although AMR infections increased significantly. Our findings facilitate the refinement of recommended surgical antibiotic prophylaxis regimens and highlight the need for a more expansive national surveillance strategy to identify changes in epidemiology. Infect Control Hosp Epidemiol 2015;36(4):409 – 416 Surgical site infections (SSIs) are healthcare-associated infections (HAIs) that contribute significantly to adverse clinical outcomes and increased healthcare costs. 1 Reported rates vary according to surgical procedure, spanning <1% for clean procedures 2 to 30% for some colorectal procedures. 3–6 Standardized surveillance has long been recognized as a minimum and necessary requirement for effectual prevention strategies, 7–9 and diminishing SSI rates have been noted following the implementation of surveillance programs. 10 Surveillance data have recently been used to evaluate appropriateness of surgical antimicrobial prophylaxis in the United States. 11 In Australia, national guidelines for surgical antibiotic prophylaxis are widely available. 12 However, evaluation of pathogen-specific data concerning infections complicating the range of surgical procedures has not been performed to deter- mine whether guidelines are concordant with local epidemiology. In 2002, the Victorian Healthcare-Associated Infection Surveillance System (VICNISS) commenced monitoring of SSIs. 13,14 The objectives of this study were (1) to examine rates of SSIs according to operative procedure groups and (2) to analyze trends over time for SSI rates, pathogens responsible for SSIs, and antimicrobial susceptibility of pathogens responsible for SSIs in Victorian hospitals for the period October 1, 2002, to June 30, 2013. methods The VICNISS program was established to monitor a range of HAI processes and outcomes in Victorian hospitals, including SSIs. 15 The SSI surveillance module is based on the National Healthcare Safety Network (NHSN), Centers for Disease Control and Prevention (CDC). 16,17 For the current study, Affiliation: Victorian Healthcare Associated Infection Surveillance System (VICNISS) Coordinating Centre, Melbourne, Victoria, 3000, Australia. © 2015 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2015/3604-0006. DOI: 10.1017/ice.2014.70 Received July 16, 2014; accepted November 30, 2014; electronically published January 20, 2015 infection control & hospital epidemiology april 2015, vol. 36, no. 4