D R MacFadden1, B Coburn2, N Shah3, A Robicsek4, R Savage5, M Elligsen6, N Daneman7. 1. Division of Infectious Diseases, University of Toronto, Toronto, Canada. Electronic address: derek.macfadden@mail.utoronto.ca. 2. Division of Infectious Diseases, University of Toronto, Toronto, Canada. 3. Division of Infectious Diseases, NorthShore University Health Systems, Chicago, IL, USA. 4. Critical Care and Population Health, Providence St Joseph Health, Burbank, CA, USA. 5. Dalla Lana School of Public Health, University of Toronto, Toronto, Canada. 6. Department of Pharmacy, Sunnybrook Health Sciences Centre, University of Toronto, Canada. 7. Division of Infectious Diseases, University of Toronto, Toronto, Canada; Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Canada.
Abstract
OBJECTIVES: Appropriate empiric antibiotic therapy in patients with bloodstream infections due to Gram-negative pathogens can improve outcomes. We evaluated the utility of prior microbiologic results for guiding empiric treatment in Gram-negative bloodstream infections. METHODS: We conducted a multicentre observational cohort study in two large health systems in Canada and the United States, including 1832 hospitalized patients with Gram-negative bloodstream infection (community, hospital and intensive care unit acquired) from April 2010 to March 2015. RESULTS: Among 1832 patients with Gram-negative bloodstream infection, 28% (n = 504) of patients had a documented prior Gram-negative organism from a nonscreening culture within the previous 12 months. A most recent prior Gram-negative organism resistant to a given antibiotic was strongly predictive of the current organism's resistance to the same antibiotic. The overall specificity was 0.92 (95% confidence interval (CI) 0.91-0.93), and positive predictive value was 0.66 (95% CI 0.61-0.70) for predicting antibiotic resistance. Specificities and positive predictive values ranged from 0.77 to 0.98 and 0.43 to 0.78, respectively, across different antibiotics, organisms and patient subgroups. Increasing time between cultures was associated with a decrease in positive predictive value but not specificity. An heuristic based on a prior resistant Gram-negative pathogen could have been applied to one in four patients and in these patients would have changed therapy in one in five. CONCLUSIONS: In patients with a bloodstream infection with a Gram-negative organism, identification of a most recent prior Gram-negative organism resistant to a drug of interest (within the last 12 months) is highly specific for resistance and should preclude use of that antibiotic.
OBJECTIVES: Appropriate empiric antibiotic therapy in patients with bloodstream infections due to Gram-negative pathogens can improve outcomes. We evaluated the utility of prior microbiologic results for guiding empiric treatment in Gram-negative bloodstream infections. METHODS: We conducted a multicentre observational cohort study in two large health systems in Canada and the United States, including 1832 hospitalized patients with Gram-negative bloodstream infection (community, hospital and intensive care unit acquired) from April 2010 to March 2015. RESULTS: Among 1832 patients with Gram-negative bloodstream infection, 28% (n = 504) of patients had a documented prior Gram-negative organism from a nonscreening culture within the previous 12 months. A most recent prior Gram-negative organism resistant to a given antibiotic was strongly predictive of the current organism's resistance to the same antibiotic. The overall specificity was 0.92 (95% confidence interval (CI) 0.91-0.93), and positive predictive value was 0.66 (95% CI 0.61-0.70) for predicting antibiotic resistance. Specificities and positive predictive values ranged from 0.77 to 0.98 and 0.43 to 0.78, respectively, across different antibiotics, organisms and patient subgroups. Increasing time between cultures was associated with a decrease in positive predictive value but not specificity. An heuristic based on a prior resistant Gram-negative pathogen could have been applied to one in four patients and in these patients would have changed therapy in one in five. CONCLUSIONS: In patients with a bloodstream infection with a Gram-negative organism, identification of a most recent prior Gram-negative organism resistant to a drug of interest (within the last 12 months) is highly specific for resistance and should preclude use of that antibiotic.
Authors: Michael S Niederman; Rebecca M Baron; Lila Bouadma; Thierry Calandra; Nick Daneman; Jan DeWaele; Marin H Kollef; Jeffrey Lipman; Girish B Nair Journal: Crit Care Date: 2021-08-26 Impact factor: 9.097
Authors: Derek R MacFadden; Roberto G Melano; Bryan Coburn; Nathalie Tijet; William P Hanage; Nick Daneman Journal: J Clin Microbiol Date: 2019-05-24 Impact factor: 5.948
Authors: Elio Castagnola; Francesca Bagnasco; Alessio Mesini; Philipp K A Agyeman; Roland A Ammann; Fabianne Carlesse; Maria Elena Santolaya de Pablo; Andreas H Groll; Gabrielle M Haeusler; Thomas Lehrnbecher; Arne Simon; Maria Rosaria D'Amico; Austin Duong; Evgeny A Idelevich; Marie Luckowitsch; Mariaclaudia Meli; Giuseppe Menna; Sasha Palmert; Giovanna Russo; Marco Sarno; Galina Solopova; Annalisa Tondo; Yona Traubici; Lillian Sung Journal: Antibiotics (Basel) Date: 2021-03-05