Healthcare-associated infections due to multidrug-resistant organisms: a surveillance study on extra hospital stay and direct costs

BACKGROUND: The increasing antimicrobial resistance poses a challenge for surveillance systems and raises concerns about the impact of multidrug-resistant organisms on patient safety. OBJECTIVE: To estimate extra hospital stay and economic burden of infections due to alert organisms - mostly multidrug-resistant - in a teaching hospital. METHODS: The present retrospective matched cohort study was conducted through the analysis of hospital admissions at Sant'Andrea Teaching Hospital in Rome from April to December 2015. Extra hospital stay was the difference in the length of stay between each case and control. All patients developing an infection due to an alert organism were considered cases, all others were eligible as controls. The costs of LOS were evaluated by multiplying the extra stay with hospital daily cost. RESULTS: Overall 122 patients developed an infection due to alert an organism and were all matched with controls. The attributable extra stay was 2,291 days (mean 18.8; median 19.0) with a significantly increased hospitalization in intensive care units (21.2 days), bloodstream infections (52.5 days), and infections due to Gram-negative bacteria (mean 29.2 days; median 32.6 days). Applying the single day hospital cost, the overall additional expenditure was 11,549 euro per patient. The average additional cost of antibiotic drugs for the treatment of infections was about 1,200 euro per patient. CONCLUSIONS: The present study presents an accurate mapping of the clinical and economic impact of infections attributable to alert organisms demonstrating that infections due to multidrug-resistant organisms are associated with higher mortality, longer hospital stays, and increased costs.