Epidemiology of Surgical Site Infections Considering the NHSN Standardized Infection Ratio in Hip and Knee Arthroplasties

Introduction Surgical site infections (SSIs) are a predominant form of hospital-acquired infections in surgical wards. The objective of the study was analysis of the incidence of SSI in, both primary and revision, hip and knee arthroplasties. Material and methods: The study was conducted in 2012-2018 in a Trauma and Orthopedics Ward in Tarnow according to the methodology of the Healthcare-Associated Infections Surveillance Network (HAI-Net), European Centre for Disease Prevention and Control (ECDC). Results: The surveillance comprised 2340 surgery patients, including: 1756 Hip Arthroplasties (HPRO) and 584 Knee Arthroplasties (KPRO). In the group of patients under study, 37 cases of SSI were detected, including: 26 cases of SSI after HPRO and 11 cases in KPRO. The average incidence of SSI amounted to 1.6% (1.5% HPRO and 1.9% KPRO) and in-hospital incidence density rates were 1.23 and 1.53 per 1000 patient-days, respectively. Median age of surgical patients in both HPRO and KPRO was 70 years. Women were undergoing arthroplasty surgery more often than men, HPRO (p < 0.05) and KPRO (p < 0.001). Patients with SSI stayed in the ward longer (SSI-HPRO, p < 0.001) (SSI-KPRO p < 0.01). In KPRO operations, the incidence of SSI was higher than expected, calculated according to the Standardized Infection Ratio (SIR). The most common etiologic agents isolated from SSIs in both HPRO and KPRO were coagulase-negative staphylococci. Conclusions: Establishing a thorough surveillance of hospital-acquired infections that takes into consideration epidemiological indicators is indispensable to properly assess the epidemiological situation in the ward. The optimal solution is to carry out long-term and multi-center surveillance in the framework of a uniform program, however, even results of single-center studies provide valuable data indicating challenges and needs in improving patient safety.