Utility of Direct Susceptibility Testing on Blood Cultures- Is It Still Worthwhile?

Utility of Direct Susceptibility Testing on Blood Cultures- Is It Still Worthwhile?
J Med Microbiol. 2016 Apr 5;
Authors: Menon V, Lahanas S, Janto C, Lee A
Abstract
Earlier targeted therapy for bacteraemia optimises patient outcomes and reduces broad spectrum antibiotic use. Standardised susceptibility testing results are available at 36-48hrs. Direct disc susceptibility testing from blood culture broth reduces time to results but the inoculum is not standardised. No studies have looked at the clinical utility of direct susceptibility results. This retrospective cohort study aimed to assess the correlation between direct and formal testing methods as well as the clinical utility of direct susceptibility results. 160 episodes of bacteraemia with paired direct and formal susceptibility testing were studied. Direct testing was performed on blood culture broth. Formal testing was performed on isolates, using automated broth microdilution or Etests®. The rate of error was 9.1% (95% CI 7.0-11.6%) . In 10 (6.3%, 95% CI 3.0-11.2%) cases inappropriate antibiotics were used due to direct sensitivity results, including 2 cases with ineffective (as opposed to too broad) antibiotics being used. Antibiotics were changed in 28.1% of cases once direct susceptibility data was available. There was a decreased time to effective antibiotics in 9.3% (95% CI 5.3-15.0%), and a decreased time to a targeted antibiotics in 14.3% (95% CI 9.3-20.8%) of cases....

Source: Journal of Medical Microbiology - April 4, 2016 Category: Microbiology Authors: Menon V, Lahanas S, Janto C, Lee A Tags: J Med Microbiol Source Type: research