Ferreiro, José Luis Lamas

Abstract Background Treatment of high risk AmpC-producing Enterobacterales bloodstream infections (BSIs) is challenging due to the posibility of development of antibiotic resistance during treatment. The aim of this study was to analyze the impact of antimicrobial stewardship activity and IDSA guidelines adequacy in patients with high risk AmpC-producing Enterobacterales BSIs. Methods Patients with Citrobacter spp, Enterobacter spp and Klebsiella aerogenes BSIs were included between June 2019-March 2024. Outcomes of death and relapse of infection at 30 days were assessed. Adequacy of definitive antimicrobial treatment according to IDSA guidelines was evaluated. The impact of antimicrobial stewardship activity in treatment adequacy and outcome was analyzed. Analysis was performed using SPSS version 25. Results 2049 BSIs were evaluated and 67 were finally included. 80% were monomicrobial. Median patient age was 74 years, 73% were male. The most frequent microorganism isolated was Enterobacter cloacae (55%). 50% were nosocomial and the most frequent origen was biliary tract (35,8%). 35% met sepsis criteria. 30% of cases presented cefotaxim resistance. Empiric and definitive antibiotic treatment was prescribed according IDSA guidelinesi n 34% and 91% of cases, respectively.. Death at 30 days was 6% and a combination outcome of death and relapse of infection at 30 days was 11,9%. Definitive antibiotic treatment adequacy according to IDSA guidelines was associated with lower mortality and relapse at 30 days (OR 0,04; IC95 0,003-0,6; P=0,02). Antimicrobial stewardship team did an intervention in 34% cases. This intervention was associated with a trend toward of lower mortality and relapse (4% vs 15%, P=0,2), a trend toward of higher IDSA guidelines adequacy (100% vs 86%, P=0,08), and a higher switch to oral treatment (78% vs 52%; P=0,03). Conclusion Adequacy of definitive antimicrobial treatment in high risk AmpC producing Enterobacterales BSIs according to IDSA guidelines was associated with a better outcome. Antimicrobial stewardship is desired for management of these patients. Disclosures All Authors: No reported disclosures

Abstract Background A decrease in antimicrobial stewardship activities has been observed in our hospital since the beginning of the pandemic. The study aim was to evaluate the impact of decrease in antimicrobial stewardship activities in Klebsiella pneumoniae and Escherichia coli acquired multidrug-resistance. Methods The quarterly percentage of broad-spectrum antibiotic prescriptions evaluated by antimicrobial stewardship team (AMST), the quarterly consumption of broad-spectrum antimicrobials and the quarterly proportion of multidrug-resistant K. pneumoniae and E. coli were assessed between October 2016 and December 2022, with 2 periods of time, before the pandemic (October 2016-March 2020) and after the pandemic (April 2020-December 2022).Time series analysis was performed with ARIMA models to evaluate the association between decrease in AMST activities with multidrug-resistance in K. pneumoniae or E. coli. Correlation between broad-spectrum antibiotic prescriptions reviewed by AMST with broad-spectrum antimicrobials consumption and proportion of multidrug-resistance in K. pneumoniae or E. coli in urine cultures was assessed using the Pearson correlation coefficient. Results Percentage of broad-spectrum antimicrobials evaluated by AMST was 77% in first period and 29% in second period. The mean of broad-spectrum antibiotics consumption in first period was 13.02 DDD/100 bed-days and 15.35 DDD/100 bed-days in second period. Decrease of AMST activities was associated with an 37% increase in multidrug-resistant K. pneumoniae in second period compared with first period (p=0.02). No differences were found in E. coli. Correlation between percentage of AMST-reviewed broad-spectrum antibiotics with consumption of these antibiotics was good (correlation coefficient -0,7; p< 0,01). Correlation between ASMT-reviewed broad-spectrum antibiotics and multidrug-resistant K. pneumoniae was moderate (correlation coefficient -0.44; p=0,02). No correlation between ASMT-reviewed broad-spectrum antibiotics and multidrug-resistant E. coli (correlation coefficient 0,09; p=0,6) was found. Conclusion Decrease in antimicrobial stewardship activities was associated with high isolation of multidrug-resistant K. pneumoniae in urine cultures. Disclosures All Authors: No reported disclosures